Emulsion tube is leaning it out as vacuum increases. The E tube has holes that bleed air in as vacuum rises, the more holes the more it leans out, get one with less holes!
AAAAAAH MY HEART SANK WITH THAT ENGINE NOTE BEFORE IT DIED BRET , THANKYOU FOR FOR ALL YOUR MOST EXCELLENT TESTING PROCEDURES.SO MUCH TIME & EFFORT WITH FANTASTIC EXPLANATION ON ALL TESTING RUNS . THERES NOTHING LIKE THIS ON U-TUBE THAT COMES CLOSE .ABSOLUTELY GREAT INFORMATION TO ALL SCOOTER FREAK COMMUNITY, YOU ARE TRULY PROVIDING RIVETING ENTERTAINMENT ❤
Proving the EGT works is why I know you're an engineer, by honor at the least. Thanks for putting in all the work on top of the video production; and helping people figure out 2Ts the best way you can through all the research and empirical testing. It's hard work to put out expert level content on complex topics like engines and calibration, mechanical, electrical and even software making curves, this is mechatronics engineering.
I had problems with the PWK carbs that they emptying their bowls. Just dying after a couple of second in full open throttle. So i just drill out the fuelchannel from the side (its plugged there), and after that operation it fixed the problem. Maybe you have the simular problem? It just don't emptying as much and sucking a little bit of air? And that makes you engine going lean and showing high EGT. Just a thought. :)
You need to try KOSO KSR 34mm flat slide carb or the cheap replica CPO flat slide carb 34mm. You will only need to adjust pilot and mainjet and not the needle. Give it a try. Way easier to tune i guarantee
What the heck??? I never would have thought dialing in a top quality carb could be so much trouble... Sorry about your top end... This is turning into $$$... Looking forward to watching you figure this thing out.
Its a known problem on those carbs and on the really china stuff also, the fuel inlet has some material inproperties often so that not enough fuel get into that carb, thats why u can change mainjet as long as u want without result.. some people get a drill and drill out the bronze ball below the fuel inlet on the carb to get the blocked inlet canal free from casting issues what causing this.. afterwarts in the drilled hole they tap it and secure it again with a screw.. hope i could help you with this one ! :D if u need more info write me
Also i think the 34mm is just not needed in anyway. The best size for 70-100cc build i think is something like 28pwk it has good flow area and you can have much higher intake speed
I have seen potential for quicker times with the 34mm. I've gone quicker than I have before and it's clearly still not working right. That may not say I need a 34mm PWK, but there's some advantage to it vs the 28mm VHST.
Not sure if this has been already covered, but the bigger carb probably makes bigger fuel droplets which burn slower and raise the egt. I would assume it will have less power too. 34mm carb is probably oversize, 125cc kart engines use about 30mm carbs and make over 40hp. The reed valve is so big restriction that the carb size has little effect.
That would make sense. I don't feel like it has had a fair chance yet to see if it does better than the smaller carb, but looking at average 0-60s it is promising. Some say improvements in drag racing with a big carb comes from getting more throttle opening area more quickly, but I don't know how accurate that is in my case since I have to roll in regardless to stop wheelies and I'm not really seeing 60ft or 0-30MPH change much, which is where I'm working on getting it to full throttle. Could be the case though. I don't think I'll see a huge change either way, but it would be nice if I could pick up some tenths for drag racing.
Based on my polini pwk experience i think your problem would be solved with a 30-40 hole atomizer. By installing a 30 hole atomizer you help atomize the fuel better, with more holes in it so smaller and more fuel droplets enter the engine. The low throttle response becomes much more crisp and the top end becomes much more "awake". For your setup a 180-190 jet should be spot on i think. Next time try a needle with a bottom opening of 1.05 max. Straight section on needles determines how fast the main jet engages ( shorter straight, main jet opens earlier). I would suggest a needle with a small straight section, cruising at half throttle becomes less aggresive on the engine due to the main jet engaging as well as the needle. Pilot jet should be at 48-52, but that's the last thing you will fine tune. Hope everything goes well again, and please keep providing content!
the so called "atomiser", more commonly referred to as an "emulsion tube" serves another purpose besides simply assisting fuel atomisation. the location and dimension of those holes is critical, and explains why changing or altering that tube for an alternative changes the throttle characteristics. hint, air speed through the venturi, and therefore vacuum on the jet orifice, has nothing to do with the throttle position, but rather, RPM.
This carb came with and currently uses a 30 hole atomizer. I find it interesting that the comments section is polarized on this. I have some people saying you need holes and some saying you should not use one with any holes.
@@49ccscoot block the holes up and see what happens? i can tell you what will happen, but wheres the fun in that? "atomisation" is not its primary function.
As you are running a bigger carburettor, then running at full power will naturally produce much more combustion gases. As you are running the same expansion chamber, you could be hitting the limit of the current pipe with respect to stinger diameter. If this is the case then this will quickly lead to high exhaust temperature. Try running a pipe with a slightly bigger stinger diameter to see how this relates to EGT at full power and take it from there. Hope this helps 🙂
Thanks for the idea. There are 2 people that I have rode with that use 34mm carbs with the same setup I have. Seems like a lot of people use them on the RC-One without swapping anything else. That's the part that baffles me. Everyone else seems to have no trouble with any of this.
@@49ccscoot Remember no two engines/scooters are ever exactly the same and it may be that yours is just hitting the limit! ...... and a simple exhaust swap with bigger stinger diameter will put any doubts quickly to bed.
I wonder if total vehicle weight affects tuning. That might account for why what works for you seems to be often somewhat different from what works best for others with similar setups.
I've tuned carbs for much smaller customers in the past and never had someone come back and tell me it didn't run right. I would think it's working as hard as it can at any given throttle position anyway and it's more a matter of how quickly it accelerates due to the weight. If anything, I'd almost think you'd need richer part throttle setting for lighter riders because they may reach higher speed/RPM at lower throttle settings. Also, if weight affected jetting then gear ratio probably should too. I haven't switched gears around a lot, but I don't ever remember carb trouble as part of final drive ratio changes. Maybe if the CVT is off. Kind of like how you test for spark knock in a manual by operating in a higher gear than you should be to put it under high load at low revs. I've tuned CVTs to low RPM and had spark knock happen for the same reason, but that was low powered stuff and I only recall it in 4Ts. If this thing struggled like that it would fall totally out of the pipe's working range anyway.
Hello from Norway 🥳 I love your contect, youre so thorough in your testing and you have been a nice influence on me 🫶 I'm waiting this spark plug sensor for my malossi 70cc sport. What working temperature should I achieve with a well tuned carb?
Emulsion tube, don't know what it's called in USA. The tube under the needle that leads to main jet has holes that bleed in air as vacuum increases leaning it out, the more holes the leaner the top end. It's not all needle, it's about the difference between maximum and minimum demand at full throttle.
Hope you will get it to work again 🎉 Today I made demon from my Piaggio Sfera by changing rollers from 6 to 4 grams and installing Stage6 R/T clutch and belt 😂 I’m waiting for tomorrows testing
@@49ccscootOn a small 2 stroke (49mmx40mm) with 19.5mm Dellorto phbg clone. Should I use a 2 stroke only emulsion_atomizer tube jet that had no holes (#AU ) Or #AN that has holes & is supposed to work with both 4 & 2 stroke engines?
If removing the main jet makes no difference, then it will be either, or both, of these two reasons. 1. The circular area of the needle, in its relative position to the top of the needle jet at full opening, subtracted from circular area of the needle jet, is less than the circular area of the main jet, meaning that the needle, and its jet, are acting as the main jet no matter how large you go with the actual main jet. 2. In sufficient fuel is entering the float bowl. A good test for 2. is to remove the float bowl and hold the float in the position you think it will be in, in normal use, and turn the fuel on, to see the rate that it flows. If it comes out like a man trying to piss with an enlarged prostate, then that will be the problem, and you will need to either get a larger float jet, and/or drill out the fuel galleries
It's astonishing how accurate you are but I'd add a few points 1. On the cylinder wall it looks like melted aluminium from the piston, I wouldn't worry 2. Every few miles/kms while changing jets the spark plug needs to be checked. The colour shows where you are with the mixture and you've missed this step 3. As a european it's funny to see you're playing with 94cc race engine on the road :D But it shows that you don't use it for racing --> your jetting should be on the safe side: slightly lower EGT but slightly worse acceleration results than on spot. And because you don't race I'd set a jetting to every environmental condition to avoid seizing and rejetting all the time. 4. For a good jetting you don't need to touch the ignition 5. I'm racing with 70cc and my knowledge is enough for a quite good base jetting (Dellorto carb) but not for a sharp race jetting --> my strategy: the most important are the idle and main jets' balance, I don't touch the needle, because: for the behavior around 0-1/3 of TP the idle jet rules over the needle and above 3/4 of TP the main and idle jets together are the important parameters. I felt that your idle jet is too small and the main is too rich. So I'd give it bigger idle jet (and maybe a different pilot jet, but I don't like pilot jets) which should help to decrease EGT. Sometimes incredibly big main jet supports the engine at high speed for optimal operation in that case smaller main jet can be enough for safe operation 6. With the needle you can set only the transition --> for me the most important about the needle is that it can control only the amount of fuel which comes from the main jet --> with the needle you don't control the fuel quantity but only the air-fuel quality in the transition area (I've seen engine with rich needle and relatively small jetting and they seized many times).
Thanks for the comments. 1. Tune in next week for cylinder restoration efforts. 2. I have actually taken the plug out and cut it so I could see the whole insulator a couple of times. I don't much like peering down in there otherwise. Some seem to have no trouble, but if I'm going to do it I like to have a clear view of the mixture ring. I haven't really got to a point of fine tuning part throttle yet to make upper porcelain coloring terribly relevant to me yet. In general, I've just had more luck with results based tuning rather than plug reading and tend to fall back on plug reading if I'm in a jam and can't tell what's happening. 3. This is the one good thing about being in an area where people generally don't like or care about scoots. I don't know what I'd do with my life if unable to ride these regularly. lol Also, I tend to choose a main jet on the richer side of good results and once that's set the EGT will generally show me if some environmental condition is problematic. At least with the VHST, it hasn't been as bad as I expected. 4. Generally no, but clearly something is wrong when you're taking the main jet out to get acceptable temps. I also think the rounder slides deal with part throttle issues better and my timing at lower throttle/RPM is now an issue. Thinking back to the Lectron on my 86cc, it seemed impossible to get right and I was using the same ignition there and the round slide that was on before the Lectron worked just fine without a lot of hassle. 5. I've had similar results with different pilot jets. This carb actually seems to separate the pilot/mix screw from other functions more than anything that I'm used to. On some carbs the main jet swings that I've had could drastically affect idle and even starting, but this thing seems like once the idle is set it's pretty good to go. That said, if operating at very low throttle I don't disagree that the pilot being on the rich side may be a good thing.
MVT employee told me never go higher 0.4 on a mvtDD. For your high end config a malossi italkit or better a PVL (bidalot ) would be more suitable. 34 pwk are known for having fuel flow issues. Pwk are really sensitive about idle jet set up. Should not be less than 50. With my high end 70cc with a 28 pwk setup was 155 /48 jjh 8 holes. Dont know if it can help. Wish you to restore the engine easily. Br
Could try tuning without the variator shims, probably revving to much and can’t reach top speeds with the shims installed, i feel it would be good for short bursts tho, wrong variator set up made my tuning all over the place
I have a 50cc athena racing bore, c16 and polini pwk28mm, very overkill but somehow made it work lol, the variator was decently heavy but top speeds was there, bottom end sucked cuz wrong torque spring and i thought it was just rich jetting but plug was always lean, i like starting off with rich enough tune and figuring out trans first without shims so i can test the full rpm range
I definitely want to see a more standard carb (this PWK) work before I attempt that. At this point, I think the timing curve is what made this and the Lectron so hard to work with. If I straighten that out, the Lectron may not be nearly as bad as my first experience... maybe.
Can't say for sure yet, but my thought is that it's way too much timing anywhere below wide open RPM. Could possibly still be some carb tuning stuff. Emulsion tube is one suspect. I'm still waiting on a piston and a new ignition to see how it goes.
I am sorry about your engine. I am not sure if "press like if you enjoyed it" applies here. I suspect, and perhaps you do to, that your old carb may have been closer to optimal than the larger one. If you should again deviate from that, I would hope that you get something only one size up, instead of what you last ran. In the end, and as you know, if you add more air, you have to add an equal portion more of fuel, and if you are making more power--the engine will run warmer--regardless. As you stated about the position of the combustion in the exhaust port, that may likely be. Additionally, perhaps the larger carb just has too much port to keep the fuel mixed well and intake air from being turbulent. The only things I could think that might help your set up are, perhaps trying a plug that is one small step cooler. It would likely make it run rougher on start. If it were possible to torque it accurately, I might put copper anti-seize on the plug threads to make sure that thermally, the plug and head are one. Obviously, you don't want to put anything on the plug that will give you a false torque reading. During a rebuild head flatness would be something to check. [I wonder if increasing the oil/fuel mixture might help during testing?] These are also minor, but... I might still try to get whichever carb you have off of the fender, so that unnecessary vibration isn't coupled to the engine, which might make the bowl valve bounce around. The rubber on the intake helps with heat--and may be there for vibration. Changing or ensuring that the air-filter has an integrated velocity stack might straighten the airflow into the motor. If you look at a wind tunnel, they have a large bell-mouth, which attempts to match the restriction of the tunnel with the wide-open air. They have one or more screens to smooth the airflow and make it laminar, and that would restrict the airflow--IF the bellmouth wasn't wider than the hold in the carb to compensate for it in the first place. Though, the bellmouth diffuser is there to smooth the flow. Oddly, even shielding the air-filter from buffeting wind may help with performance. I pretty am sure that adding something like a properly-designed motorcycle airbox would slow your scooter off the line, but, it might help with the overall time and speed. Once again, I am sorry about your top end.
Thanks for the comments. I would like to use an airbox at some point, but because I try to document everything I haven't just mounted one on there yet. My experience has been that they improve day to day operation by keeping the tune more stable. I didn't notice a decline in performance, but it may be different with the power levels that I'm at now vs the old setups that I tried. BTW, likes are appropriate. Likes are showing creators that you like what they're doing... they did a good job on the video production, it's an interesting topic, and so on and likes will help the creator by making the video more easy for others to find. You're not saying that you like their hardship. Not sure what the etiquette is for serious life or health related videos TBH, but this is just parts and can be replaced. Thanks for the thoughtfulness though.
Hey Brent! I have a quick question, what is the optimal temp for a liquid cooled racing setup. I have a S6 R/t with an 80°C water temp. The problem I had was the piston seezed just from the two sides upper from the pin area. Was the overall water temp too high? The carb was tuned for rich for sure, it wasn't lean what I was seeing.
Mine runs 120-140F mostly, so 40-55F cooler than 80C roughly. Some bikes have thermostats that try to keep them hotter than that though. That shouldn't cause it to fail on it's own. It may be hot from ignition timing or something else in the setup. You can try to verify timing with a timing light to make sure it's where you think it should be. Definitely make sure squish is set to spec. Good oil supply... I run mine 4oz per gallon or 32:1.
I don't have a thermostat. It's a racing engine too. 70cc 26pwk carb, 115main jet, 32 power jet. Stock ignition with a top performance cdi with a different pre ignition as I red on the manual. Squish is a bit bigger than the factory specs, about 0.1mm bigger If I remember correctly. I use motul 710 racing oil. 1:33. Carb tuning can be off, I might try to take out my power jet and tune it only by main. But if Im honest, I couldn't really tried full throttle spark plug checks, I used my scoot mostly in the city, this happened on my first longer high speed ride. But thanks for your answer! I'm looking forward for any more tips.
@@pepelazy3249 I've taken mine to an industrial park before on a day when most businesses close. It had a long enough road for me to do 1/8 mile runs and slow down. Carried main jets with me and the tools to change them. That was the quickest that I've ever gone through a range of jets for tuning. I use a dragy and I film my runs with a helmet cam that sees my gauges so I can just do the jet runs and then analyze later, but you don't have to have all of that. Dragy has been a great tuning tool for me. Timing from video before that was consistent, but the dragy is amazing and gives more data instantly and very accurately. It can't tell you if the tune is safe, but you can see what works for power easier. Generally a step richer than peak performance is a safe enough tune, but sometimes it gets tougher than that. dragy : amzn.to/3Rxm2Lb (affiliate link)
@@49ccscoot yes for sure this is the easiest method for fine tuning, I've seen that video too. I don't have a dragy but I can mark a 1/8 mile line from start to finish, and than I can measure time, basically the same as yours, maybe a bit more complicated, than just check my phone for the restuls. And from what I have seen in your carb tuning videos, you have problems too finding a jet that works perfect in lower and higher revs too. So I will take my time for this, it isn't a fast process. Thanks for your time. I learned a lot lot from your videos and experience.
I know this isnt a factor in the failure but i am just curious as to what two stroke oil you use and why. If you already have a video on that subject i will try to find it.
holy shit 91-93 is premium in us? our standard is 95, and you can get a sportier 98 with nearly no cost up, and "ultimate" 102 octane easily at nearly every gas station. @@49ccscoot
@@49ccscoot thank you sir! I modify chainsaws and string trimmers and appreciate the detail in your channel. There isnt much that crosses over but the oil subject always interests me.
@@49ccscootHi mate! I want to give you an advice cause I’m from Italy and when I ran an MHR cylinder on my scoot with a variable timing ignition the manual used to say to put 100octane fuel (tha standard here is 95octane)… and I always put that…it prevent some detonation in case you are off timing… Anyway Thanks for your videos!! Great contents!!! P.S. try another setup for the ignition…
@@Super-Dave-Outdoors I actually used to use AMSOil Saber Professional. It was marketed as good for 100:1, but I mixed it 50:1 for the scoots. I switched over a few years ago because AMSOil stopped listing it for motorbikes. Since the change in both mix ratio and oil, I've noticed an improvement when I look over cylinder kits. Not sure that it would matter much in saws and trimmers that are not so high strung, but I run the same Dominator at 32:1 in my saw what little I run it since I have it around. I'd probably do the same if I had any quality 2T equipment that I care about... but then I'm not a pro running saws all day. It may seriously cut into the budget using a lot of expensive oil.
I wanted to put a 19.5mm Dellorto phbg clone on a 2 stroke 49mmx40mm motorized bicycle engine. Should I use an emulsion_atomizer tube AN with holes made for 4 strokes & w strokes....Or would the AU 2 stroke only tube with no atomizer holes in it work better???
@@49ccscoot Thanks......🤔 I seen buying an individual one costs $ about the same price as just buying it in a rebuild kit. So I can order a rebuild kit & for the same price but also get a different weight float & different size needle & jets.
I'm repeating myself sorry, but please look into it. They effect anything that uses main jet. A natural carb without the emulsion tube gets richer with air flow. And don't forget you have the power jet for top end too?
@@49ccscoot what about the emulsion tubes available? Effect the fueling curve at full throttle. I wonder if the larger carb to capacity ratio needs an e- tube with less air bleed? I bought a 24pwk copy and it came with 3 jets and 2 tubes.....I still haven't used it! I think you should do a build tuning a standard cylinder. There was a race series in France, had to use standard cylinder, but could tune it, exhaust and carb were free. 24 or 12 hour races, only about 10bhp at the wheel.
@@peterjohn3180 I've got the other emulsion tubes available for the carb. I'll be changing the ignition first, because I know 45-46 degrees at part throttle is way too much. Maybe the emulsion tube will fix the temps coming back up after the CVT was tuned though.
@49ccscoot My Banshee 421( 85whp) setup had 33mm cabs, so it's 210cc for 34mm My 521 setup (110whp) have 39mm carbs, so it's 260cc for 39mm. You're putting 34mm on a 90cc engine. I think it would be good on a drag setup, where you only tune the full open throttle (the easy part), but tuning the low and middle with a big carbs like that will not be easy bro. Keep the good work, I like your videos.
Oh the everlasting struggle. Wish someone will end-up with a bolt-on fuel injection or atleast an adjustable mainjet that could be screwed in or out while the engine is running. Some kind of spring-loaded mechanism.
There are adjustable mainjet's for old bings & mikuni vm20-24. You can also build your own adjustable mainjet for a pwk. th-cam.com/video/Vfk2qoVFKmo/w-d-xo.html 4:40 and onwards.
I think I just have a timing issue and need a better curve. 45-46 degrees is a whole lot at part throttle. There are power jets and some companies make other add-on jets. Some carb styles, do have screws for low and high throttle/speed but I've only worked with small ones on piston port midbikes.
When you Start ,must use big noozle,degrade it,untill it cant be anymore.Just as motor is alive.Something called "ionising" noozle,or something.Was 1 video of a 4wd car,Suzuki-jeep had chain-saw carburettor.Didnt see,but a saw has 70-90 ccm.Forbidden tool,farming worlds most dangerous job.Bigger than capitol home,not allowed chainsaw.Jump into you 0 second,timber-logger muscles.45-15 noozle wrc and f1 according to 1 video,pr cyilnder 200 ccm.
Big carb on small engine slows air flow down in the carb and makes it harder to pull fuel thru the main jet making it want bigger main you can get to big of a carb smaller carb higher air velocity thru carb pulls fuel thru main jet more easily
you need a 30 hole jet tube. you prolly have few holes on it or even none which is for 4 stroke engines and itll lean out your 2 stroke, because the fuel isnt pulverised, more holes means better pulverisation which means richer with less fuel. when you are squirting fuel with a 4 stroke jet tube you are wasting fuel
if your carburator iss a direct replica of a pwk you need to verify if the air hole is 2mm because if it is smaller you have the hole of a 21mm pwk. nobody talks about this but look up ''prepa carbu pwk'' french people talk about it remember that a bigger carb means slower venturi annd is good for punch but most 100cc go karts have a 19mm tillitson and produce as much power
It has a 30 hole atomizer. That's what it came with and the same that Ryan uses. If you look in the comments, others are telling me the exact opposite and saying that I need 0 holes. I tend to go with the fact that I've rode with Ryan many times. I've rode his scoot briefly. I know it works for him and his setup is not far off now and was basically the same at one point.
I hope you will listen a little... Your MVT ignition does not suit your setup in any way. Your MVT ignition must be replaced, to Malossi MHR team 2 Ignition system... See how expensive it will be for you. MVT system has been proven quite a few times now, ...... You must have a Selektra system which is variable, which gives less sealing as your engine revs up ....and which is stable in the ignition at low RPM ... and give less ignition as the engine comes up in RPM
I've got another ignition ordered since the beginning of January. Not the Malossi. It's in the same order as the backordered piston though, so it'll be awhile.
I dont see why you need the 34 carb, its not a dragrace moped its your cruiser moped, you cant get everything on a tuned high end 2-stroke power and reliability is a fine straw, go for reliability and not raw power it will break
I think I should be able to use the 34mm for both. Ryan and others do it. I really think my timing curve is too aggressive down low and not aggressive enough in the powerband. Using round or oval slide carbs has made it work well enough, but both times that I've tried to switch to flat slides on my last 2 engines has ended in disaster. The rounder slides seem to be more forgiving.
but should the timing make such a difference between 28 and 34 to be night and day difference? i hope so for you, but i don´t think thats the case. but we hopefully will all find out 🙂@@49ccscoot
@@49ccscoot you have to remember no offense youre a big guy you always gonna have higher temps then they, and timing maby is a bit to aggressive down low
@@labrikorn_3299 It does seem odd to me as well. When I first started considering timing, I was actually thinking that maybe cylinder filling would be better with the large carb and it may need less advance... but I followed what made more sense to me and mimicked timing known to work in the powerband.
hmm will not make muck sense, but maybe check also if the membrane is still ok and can close completely. (no gap between carbon membrane and membrane housing). also just a thought: could it be that the suction of the motor (the volume) is to low for that size carburator, with a nearly none restrictive air filter. => stupid idea explained: it could have not enough power to suck the fuel through the nozzle, rather then only air when its WOT. because it runs good at low to mid throttle when there is also more suction power, due the lower carb opening. just thinking loud. @@49ccscoot
![กี่หมื่นฟ้า | Your Sky Series EP.1 [1/4]](http://i.ytimg.com/vi/vLGjxFL6U_I/mqdefault.jpg)
Emulsion tube is leaning it out as vacuum increases.
The E tube has holes that bleed air in as vacuum rises, the more holes the more it leans out, get one with less holes!
AAAAAAH MY HEART SANK WITH THAT ENGINE NOTE BEFORE IT DIED BRET , THANKYOU FOR FOR ALL YOUR MOST EXCELLENT TESTING PROCEDURES.SO MUCH TIME & EFFORT WITH FANTASTIC EXPLANATION ON ALL TESTING RUNS . THERES NOTHING LIKE THIS ON U-TUBE THAT COMES CLOSE .ABSOLUTELY GREAT INFORMATION TO ALL SCOOTER FREAK COMMUNITY, YOU ARE TRULY PROVIDING RIVETING ENTERTAINMENT ❤
Thank you! Always nice to hear that people enjoy the vids!
Proving the EGT works is why I know you're an engineer, by honor at the least. Thanks for putting in all the work on top of the video production; and helping people figure out 2Ts the best way you can through all the research and empirical testing. It's hard work to put out expert level content on complex topics like engines and calibration, mechanical, electrical and even software making curves, this is mechatronics engineering.
That music when inspecting the damage hit hard
I had problems with the PWK carbs that they emptying their bowls. Just dying after a couple of second in full open throttle. So i just drill out the fuelchannel from the side (its plugged there), and after that operation it fixed the problem. Maybe you have the simular problem? It just don't emptying as much and sucking a little bit of air? And that makes you engine going lean and showing high EGT.
Just a thought. :)
Thanks for showing your results 😊
Always look forward to these videos. Always very well documented with useful information. Thanks for sharing!
You need to try KOSO KSR 34mm flat slide carb or the cheap replica CPO flat slide carb 34mm. You will only need to adjust pilot and mainjet and not the needle. Give it a try. Way easier to tune i guarantee
Try next time Mikuni TMX always had good results with this type carburetor.
What the heck??? I never would have thought dialing in a top quality carb could be so much trouble... Sorry about your top end... This is turning into $$$... Looking forward to watching you figure this thing out.
Ожидаемый результат. Спасибо за Ваши видеоролики.
Reinforcing my love of dellortos
Oh man. I was really hoping you had been abke to fogure out the issue. That's so crazy
It will be built again. Better than ever.
Ahh the infamous pwk bowl flow engine killer🎉
love when a notification pops up from you Brent :-)
Its a known problem on those carbs and on the really china stuff also, the fuel inlet has some material inproperties often so that not enough fuel get into that carb, thats why u can change mainjet as long as u want without result.. some people get a drill and drill out the bronze ball below the fuel inlet on the carb to get the blocked inlet canal free from casting issues what causing this.. afterwarts in the drilled hole they tap it and secure it again with a screw.. hope i could help you with this one ! :D if u need more info write me
Great video. Really interesting and I feel for you at the end man, its never good when an engine nips up.
Also looks like detonation has been happening and that is why the outer edge of the piston has the sand blasted look
Also i think the 34mm is just not needed in anyway. The best size for 70-100cc build i think is something like 28pwk it has good flow area and you can have much higher intake speed
I have seen potential for quicker times with the 34mm. I've gone quicker than I have before and it's clearly still not working right. That may not say I need a 34mm PWK, but there's some advantage to it vs the 28mm VHST.
Not sure if this has been already covered, but the bigger carb probably makes bigger fuel droplets which burn slower and raise the egt. I would assume it will have less power too. 34mm carb is probably oversize, 125cc kart engines use about 30mm carbs and make over 40hp. The reed valve is so big restriction that the carb size has little effect.
That would make sense. I don't feel like it has had a fair chance yet to see if it does better than the smaller carb, but looking at average 0-60s it is promising. Some say improvements in drag racing with a big carb comes from getting more throttle opening area more quickly, but I don't know how accurate that is in my case since I have to roll in regardless to stop wheelies and I'm not really seeing 60ft or 0-30MPH change much, which is where I'm working on getting it to full throttle. Could be the case though. I don't think I'll see a huge change either way, but it would be nice if I could pick up some tenths for drag racing.
Based on my polini pwk experience i think your problem would be solved with a 30-40 hole atomizer. By installing a 30 hole atomizer you help atomize the fuel better, with more holes in it so smaller and more fuel droplets enter the engine. The low throttle response becomes much more crisp and the top end becomes much more "awake".
For your setup a 180-190 jet should be spot on i think. Next time try a needle with a bottom opening of 1.05 max. Straight section on needles determines how fast the main jet engages ( shorter straight, main jet opens earlier). I would suggest a needle with a small straight section, cruising at half throttle becomes less aggresive on the engine due to the main jet engaging as well as the needle.
Pilot jet should be at 48-52, but that's the last thing you will fine tune.
Hope everything goes well again, and please keep providing content!
the so called "atomiser", more commonly referred to as an "emulsion tube" serves another purpose besides simply assisting fuel atomisation.
the location and dimension of those holes is critical, and explains why changing or altering that tube for an alternative changes the throttle characteristics.
hint, air speed through the venturi, and therefore vacuum on the jet orifice, has nothing to do with the throttle position, but rather, RPM.
This carb came with and currently uses a 30 hole atomizer. I find it interesting that the comments section is polarized on this. I have some people saying you need holes and some saying you should not use one with any holes.
@@49ccscoot block the holes up and see what happens?
i can tell you what will happen, but wheres the fun in that?
"atomisation" is not its primary function.
You can buy a deep well nut for PWK that will give the main jet a bit more reserve.
As you are running a bigger carburettor, then running at full power will naturally produce much more combustion gases. As you are running the same expansion chamber, you could be hitting the limit of the current pipe with respect to stinger diameter. If this is the case then this will quickly lead to high exhaust temperature. Try running a pipe with a slightly bigger stinger diameter to see how this relates to EGT at full power and take it from there. Hope this helps 🙂
Thanks for the idea. There are 2 people that I have rode with that use 34mm carbs with the same setup I have. Seems like a lot of people use them on the RC-One without swapping anything else. That's the part that baffles me. Everyone else seems to have no trouble with any of this.
@@49ccscoot Remember no two engines/scooters are ever exactly the same and it may be that yours is just hitting the limit! ...... and a simple exhaust swap with bigger stinger diameter will put any doubts quickly to bed.
Ouch!
Keep it up!
Is it possible that the holes in the atomizer tube maybe a limiting factor?
Could be, but Ryan is using the same one without so much trouble.
I wonder if total vehicle weight affects tuning. That might account for why what works for you seems to be often somewhat different from what works best for others with similar setups.
I've tuned carbs for much smaller customers in the past and never had someone come back and tell me it didn't run right. I would think it's working as hard as it can at any given throttle position anyway and it's more a matter of how quickly it accelerates due to the weight. If anything, I'd almost think you'd need richer part throttle setting for lighter riders because they may reach higher speed/RPM at lower throttle settings. Also, if weight affected jetting then gear ratio probably should too. I haven't switched gears around a lot, but I don't ever remember carb trouble as part of final drive ratio changes. Maybe if the CVT is off. Kind of like how you test for spark knock in a manual by operating in a higher gear than you should be to put it under high load at low revs. I've tuned CVTs to low RPM and had spark knock happen for the same reason, but that was low powered stuff and I only recall it in 4Ts. If this thing struggled like that it would fall totally out of the pipe's working range anyway.
@@49ccscoot yeah you're probably right. It was just a thought. I'm just trying to think of any possible variables.
Ha liked that brady bunch edit
Hello from Norway 🥳 I love your contect, youre so thorough in your testing and you have been a nice influence on me 🫶 I'm waiting this spark plug sensor for my malossi 70cc sport. What working temperature should I achieve with a well tuned carb?
I have a eprom cdi on my Mvt dd with 2 fast 70 and it solve my problem!
Ryan offered to let me try his EPROM, but when I looked at the curves they appeared to be just as aggressive at lower RPM.
Emulsion tube, don't know what it's called in USA.
The tube under the needle that leads to main jet has holes that bleed in air as vacuum increases leaning it out, the more holes the leaner the top end.
It's not all needle, it's about the difference between maximum and minimum demand at full throttle.
Hope you will get it to work again 🎉 Today I made demon from my Piaggio Sfera by changing rollers from 6 to 4 grams and installing Stage6 R/T clutch and belt 😂 I’m waiting for tomorrows testing
Very nice! Good luck with it.
@@49ccscootOn a small 2 stroke (49mmx40mm) with 19.5mm Dellorto phbg clone. Should I use a 2 stroke only emulsion_atomizer tube jet that had no holes (#AU ) Or #AN that has holes & is supposed to work with both 4 & 2 stroke engines?
Yo-yo yo
If removing the main jet makes no difference, then it will be either, or both, of these two reasons.
1. The circular area of the needle, in its relative position to the top of the needle jet at full opening, subtracted from circular area of the needle jet, is less than the circular area of the main jet, meaning that the needle, and its jet, are acting as the main jet no matter how large you go with the actual main jet.
2. In sufficient fuel is entering the float bowl.
A good test for 2. is to remove the float bowl and hold the float in the position you think it will be in, in normal use, and turn the fuel on, to see the rate that it flows. If it comes out like a man trying to piss with an enlarged prostate, then that will be the problem, and you will need to either get a larger float jet, and/or drill out the fuel galleries
pwk dont fill up the bowl quick enough because the fuelchannel is too thin and need to be drilled out to a larger diameter
It's astonishing how accurate you are but I'd add a few points
1. On the cylinder wall it looks like melted aluminium from the piston, I wouldn't worry
2. Every few miles/kms while changing jets the spark plug needs to be checked. The colour shows where you are with the mixture and you've missed this step
3. As a european it's funny to see you're playing with 94cc race engine on the road :D But it shows that you don't use it for racing --> your jetting should be on the safe side: slightly lower EGT but slightly worse acceleration results than on spot. And because you don't race I'd set a jetting to every environmental condition to avoid seizing and rejetting all the time.
4. For a good jetting you don't need to touch the ignition
5. I'm racing with 70cc and my knowledge is enough for a quite good base jetting (Dellorto carb) but not for a sharp race jetting --> my strategy: the most important are the idle and main jets' balance, I don't touch the needle, because: for the behavior around 0-1/3 of TP the idle jet rules over the needle and above 3/4 of TP the main and idle jets together are the important parameters. I felt that your idle jet is too small and the main is too rich. So I'd give it bigger idle jet (and maybe a different pilot jet, but I don't like pilot jets) which should help to decrease EGT. Sometimes incredibly big main jet supports the engine at high speed for optimal operation in that case smaller main jet can be enough for safe operation
6. With the needle you can set only the transition --> for me the most important about the needle is that it can control only the amount of fuel which comes from the main jet --> with the needle you don't control the fuel quantity but only the air-fuel quality in the transition area (I've seen engine with rich needle and relatively small jetting and they seized many times).
Thanks for the comments.
1. Tune in next week for cylinder restoration efforts.
2. I have actually taken the plug out and cut it so I could see the whole insulator a couple of times. I don't much like peering down in there otherwise. Some seem to have no trouble, but if I'm going to do it I like to have a clear view of the mixture ring. I haven't really got to a point of fine tuning part throttle yet to make upper porcelain coloring terribly relevant to me yet. In general, I've just had more luck with results based tuning rather than plug reading and tend to fall back on plug reading if I'm in a jam and can't tell what's happening.
3. This is the one good thing about being in an area where people generally don't like or care about scoots. I don't know what I'd do with my life if unable to ride these regularly. lol Also, I tend to choose a main jet on the richer side of good results and once that's set the EGT will generally show me if some environmental condition is problematic. At least with the VHST, it hasn't been as bad as I expected.
4. Generally no, but clearly something is wrong when you're taking the main jet out to get acceptable temps. I also think the rounder slides deal with part throttle issues better and my timing at lower throttle/RPM is now an issue. Thinking back to the Lectron on my 86cc, it seemed impossible to get right and I was using the same ignition there and the round slide that was on before the Lectron worked just fine without a lot of hassle.
5. I've had similar results with different pilot jets. This carb actually seems to separate the pilot/mix screw from other functions more than anything that I'm used to. On some carbs the main jet swings that I've had could drastically affect idle and even starting, but this thing seems like once the idle is set it's pretty good to go. That said, if operating at very low throttle I don't disagree that the pilot being on the rich side may be a good thing.
the carb is going dry
seems to be to small needle jet. i had the same problem with my carb. before i needed 165main. after change needke jet i could use 132main
What frame did you use for this set up or did you build your own ? I’m thinking about using a Yamaha Zuma 50
It's a 2004 Venton Triton. Pretty similar size to a Zuma.
MVT employee told me never go higher 0.4 on a mvtDD. For your high end config a malossi italkit or better a PVL (bidalot ) would be more suitable. 34 pwk are known for having fuel flow issues. Pwk are really sensitive about idle jet set up. Should not be less than 50. With my high end 70cc with a 28 pwk setup was 155 /48 jjh 8 holes. Dont know if it can help. Wish you to restore the engine easily. Br
You need the Malossi MHR team 2 ignigtion …. I promes you that Will give You much more power
Could try tuning without the variator shims, probably revving to much and can’t reach top speeds with the shims installed, i feel it would be good for short bursts tho, wrong variator set up made my tuning all over the place
I have a 50cc athena racing bore, c16 and polini pwk28mm, very overkill but somehow made it work lol, the variator was decently heavy but top speeds was there, bottom end sucked cuz wrong torque spring and i thought it was just rich jetting but plug was always lean, i like starting off with rich enough tune and figuring out trans first without shims so i can test the full rpm range
RPM drops off too much with speed and it doesn't take off the same with 0 shims.
🔥🔥🔥👍👍👍
Try the lectron next
I bet this motor will love it
I definitely want to see a more standard carb (this PWK) work before I attempt that. At this point, I think the timing curve is what made this and the Lectron so hard to work with. If I straighten that out, the Lectron may not be nearly as bad as my first experience... maybe.
So what's the conclusion? Did your melt happen because of mvt? I have melted two pistons, dispite dyno with wide band o2 sensor to jet it.
Can't say for sure yet, but my thought is that it's way too much timing anywhere below wide open RPM. Could possibly still be some carb tuning stuff. Emulsion tube is one suspect. I'm still waiting on a piston and a new ignition to see how it goes.
I am sorry about your engine. I am not sure if "press like if you enjoyed it" applies here.
I suspect, and perhaps you do to, that your old carb may have been closer to optimal than the larger one. If you should again deviate from that, I would hope that you get something only one size up, instead of what you last ran. In the end, and as you know, if you add more air, you have to add an equal portion more of fuel, and if you are making more power--the engine will run warmer--regardless.
As you stated about the position of the combustion in the exhaust port, that may likely be. Additionally, perhaps the larger carb just has too much port to keep the fuel mixed well and intake air from being turbulent.
The only things I could think that might help your set up are, perhaps trying a plug that is one small step cooler. It would likely make it run rougher on start. If it were possible to torque it accurately, I might put copper anti-seize on the plug threads to make sure that thermally, the plug and head are one. Obviously, you don't want to put anything on the plug that will give you a false torque reading. During a rebuild head flatness would be something to check.
[I wonder if increasing the oil/fuel mixture might help during testing?]
These are also minor, but...
I might still try to get whichever carb you have off of the fender, so that unnecessary vibration isn't coupled to the engine, which might make the bowl valve bounce around. The rubber on the intake helps with heat--and may be there for vibration.
Changing or ensuring that the air-filter has an integrated velocity stack might straighten the airflow into the motor. If you look at a wind tunnel, they have a large bell-mouth, which attempts to match the restriction of the tunnel with the wide-open air. They have one or more screens to smooth the airflow and make it laminar, and that would restrict the airflow--IF the bellmouth wasn't wider than the hold in the carb to compensate for it in the first place. Though, the bellmouth diffuser is there to smooth the flow. Oddly, even shielding the air-filter from buffeting wind may help with performance. I pretty am sure that adding something like a properly-designed motorcycle airbox would slow your scooter off the line, but, it might help with the overall time and speed.
Once again, I am sorry about your top end.
Thanks for the comments. I would like to use an airbox at some point, but because I try to document everything I haven't just mounted one on there yet. My experience has been that they improve day to day operation by keeping the tune more stable. I didn't notice a decline in performance, but it may be different with the power levels that I'm at now vs the old setups that I tried.
BTW, likes are appropriate. Likes are showing creators that you like what they're doing... they did a good job on the video production, it's an interesting topic, and so on and likes will help the creator by making the video more easy for others to find. You're not saying that you like their hardship. Not sure what the etiquette is for serious life or health related videos TBH, but this is just parts and can be replaced. Thanks for the thoughtfulness though.
Hey Brent! I have a quick question, what is the optimal temp for a liquid cooled racing setup. I have a S6 R/t with an 80°C water temp. The problem I had was the piston seezed just from the two sides upper from the pin area. Was the overall water temp too high? The carb was tuned for rich for sure, it wasn't lean what I was seeing.
Mine runs 120-140F mostly, so 40-55F cooler than 80C roughly. Some bikes have thermostats that try to keep them hotter than that though. That shouldn't cause it to fail on it's own. It may be hot from ignition timing or something else in the setup. You can try to verify timing with a timing light to make sure it's where you think it should be. Definitely make sure squish is set to spec. Good oil supply... I run mine 4oz per gallon or 32:1.
I don't have a thermostat. It's a racing engine too. 70cc 26pwk carb, 115main jet, 32 power jet. Stock ignition with a top performance cdi with a different pre ignition as I red on the manual. Squish is a bit bigger than the factory specs, about 0.1mm bigger If I remember correctly. I use motul 710 racing oil. 1:33. Carb tuning can be off, I might try to take out my power jet and tune it only by main. But if Im honest, I couldn't really tried full throttle spark plug checks, I used my scoot mostly in the city, this happened on my first longer high speed ride.
But thanks for your answer! I'm looking forward for any more tips.
@@pepelazy3249 I've taken mine to an industrial park before on a day when most businesses close. It had a long enough road for me to do 1/8 mile runs and slow down. Carried main jets with me and the tools to change them. That was the quickest that I've ever gone through a range of jets for tuning. I use a dragy and I film my runs with a helmet cam that sees my gauges so I can just do the jet runs and then analyze later, but you don't have to have all of that. Dragy has been a great tuning tool for me. Timing from video before that was consistent, but the dragy is amazing and gives more data instantly and very accurately. It can't tell you if the tune is safe, but you can see what works for power easier. Generally a step richer than peak performance is a safe enough tune, but sometimes it gets tougher than that.
dragy : amzn.to/3Rxm2Lb (affiliate link)
@@49ccscoot yes for sure this is the easiest method for fine tuning, I've seen that video too. I don't have a dragy but I can mark a 1/8 mile line from start to finish, and than I can measure time, basically the same as yours, maybe a bit more complicated, than just check my phone for the restuls. And from what I have seen in your carb tuning videos, you have problems too finding a jet that works perfect in lower and higher revs too. So I will take my time for this, it isn't a fast process.
Thanks for your time. I learned a lot lot from your videos and experience.
@@pepelazy3249 There are free acceleration apps. They are not nearly as accurate as a dragy, but they may be helpful.
I know this isnt a factor in the failure but i am just curious as to what two stroke oil you use and why. If you already have a video on that subject i will try to find it.
I use AMSOil Dominator Racing 2T oil and mix it at 4oz per gallon (32:1) with premium pump gas that is 91-93 octane (R+M)/2 around here.
holy shit 91-93 is premium in us?
our standard is 95, and you can get a sportier 98 with nearly no cost up, and "ultimate" 102 octane easily at nearly every gas station. @@49ccscoot
@@49ccscoot thank you sir! I modify chainsaws and string trimmers and appreciate the detail in your channel. There isnt much that crosses over but the oil subject always interests me.
@@49ccscootHi mate! I want to give you an advice cause I’m from Italy and when I ran an MHR cylinder on my scoot with a variable timing ignition the manual used to say to put 100octane fuel (tha standard here is 95octane)… and I always put that…it prevent some detonation in case you are off timing… Anyway Thanks for your videos!! Great contents!!!
P.S. try another setup for the ignition…
@@Super-Dave-Outdoors I actually used to use AMSOil Saber Professional. It was marketed as good for 100:1, but I mixed it 50:1 for the scoots. I switched over a few years ago because AMSOil stopped listing it for motorbikes. Since the change in both mix ratio and oil, I've noticed an improvement when I look over cylinder kits. Not sure that it would matter much in saws and trimmers that are not so high strung, but I run the same Dominator at 32:1 in my saw what little I run it since I have it around. I'd probably do the same if I had any quality 2T equipment that I care about... but then I'm not a pro running saws all day. It may seriously cut into the budget using a lot of expensive oil.
What site did you use in the video?
The calculators are on my site. 49ccScoot.Com
I wanted to put a 19.5mm Dellorto phbg clone on a 2 stroke 49mmx40mm motorized bicycle engine. Should I use an emulsion_atomizer tube AN with holes made for 4 strokes & w strokes....Or would the AU 2 stroke only tube with no atomizer holes in it work better???
Most use the AU.
@@49ccscoot Thanks......🤔 I seen buying an individual one costs $ about the same price as just buying it in a rebuild kit. So I can order a rebuild kit & for the same price but also get a different weight float & different size needle & jets.
I'm repeating myself sorry, but please look into it. They effect anything that uses main jet.
A natural carb without the emulsion tube gets richer with air flow.
And don't forget you have the power jet for top end too?
Thanks. No power jet on this carb.
@@49ccscoot what about the emulsion tubes available?
Effect the fueling curve at full throttle.
I wonder if the larger carb to capacity ratio needs an e- tube with less air bleed?
I bought a 24pwk copy and it came with 3 jets and 2 tubes.....I still haven't used it!
I think you should do a build tuning a standard cylinder.
There was a race series in France, had to use standard cylinder, but could tune it, exhaust and carb were free. 24 or 12 hour races, only about 10bhp at the wheel.
@@peterjohn3180 I've got the other emulsion tubes available for the carb. I'll be changing the ignition first, because I know 45-46 degrees at part throttle is way too much. Maybe the emulsion tube will fix the temps coming back up after the CVT was tuned though.
Bigger carbs = always harder to tune.
Add a difficulty increase for flat slides as well I think. I believe the rounder slides are more forgiving.
@49ccscoot My Banshee 421( 85whp) setup had 33mm cabs, so it's 210cc for 34mm
My 521 setup (110whp) have 39mm carbs, so it's 260cc for 39mm.
You're putting 34mm on a 90cc engine. I think it would be good on a drag setup, where you only tune the full open throttle (the easy part), but tuning the low and middle with a big carbs like that will not be easy bro.
Keep the good work, I like your videos.
F's in the chat for RC1
Oh the everlasting struggle. Wish someone will end-up with a bolt-on fuel injection or atleast an adjustable mainjet that could be screwed in or out while the engine is running. Some kind of spring-loaded mechanism.
Lectron carb can offer that, they are easily adjustable with the engine running
There are adjustable mainjet's for old bings & mikuni vm20-24. You can also build your own adjustable mainjet for a pwk. th-cam.com/video/Vfk2qoVFKmo/w-d-xo.html 4:40 and onwards.
I think I just have a timing issue and need a better curve. 45-46 degrees is a whole lot at part throttle.
There are power jets and some companies make other add-on jets. Some carb styles, do have screws for low and high throttle/speed but I've only worked with small ones on piston port midbikes.
oh boy :(
It may sound weird, but you never checked the powerjet
It doesn't have one.
@49ccscoot oh, my bad i was thinking of another pwk carb sorry
Hey Brent this is for me a sad video 😢
Not much fun for me either... but it'll be back!
When you Start ,must use big noozle,degrade it,untill it cant be anymore.Just as motor is alive.Something called "ionising" noozle,or something.Was 1 video of a 4wd car,Suzuki-jeep had chain-saw carburettor.Didnt see,but a saw has 70-90 ccm.Forbidden tool,farming worlds most dangerous job.Bigger than capitol home,not allowed chainsaw.Jump into you 0 second,timber-logger muscles.45-15 noozle wrc and f1 according to 1 video,pr cyilnder 200 ccm.
Big carb on small engine slows air flow down in the carb and makes it harder to pull fuel thru the main jet making it want bigger main you can get to big of a carb smaller carb higher air velocity thru carb pulls fuel thru main jet more easily
you need a 30 hole jet tube. you prolly have few holes on it or even none which is for 4 stroke engines and itll lean out your 2 stroke, because the fuel isnt pulverised, more holes means better pulverisation which means richer with less fuel.
when you are squirting fuel with a 4 stroke jet tube you are wasting fuel
if your carburator iss a direct replica of a pwk you need to verify if the air hole is 2mm because if it is smaller you have the hole of a 21mm pwk. nobody talks about this but look up ''prepa carbu pwk'' french people talk about it
remember that a bigger carb means slower venturi annd is good for punch but most 100cc go karts have a 19mm tillitson and produce as much power
It has a 30 hole atomizer. That's what it came with and the same that Ryan uses. If you look in the comments, others are telling me the exact opposite and saying that I need 0 holes. I tend to go with the fact that I've rode with Ryan many times. I've rode his scoot briefly. I know it works for him and his setup is not far off now and was basically the same at one point.
I hope you will listen a little... Your MVT ignition does not suit your setup in any way. Your MVT ignition must be replaced, to
Malossi MHR team 2 Ignition system... See how expensive it will be for you. MVT system has been proven quite a few times now, ...... You must have a Selektra system which is variable, which gives less sealing as your engine revs up ....and which is stable in the ignition at low RPM ... and give less ignition as the engine comes up in RPM
I've got another ignition ordered since the beginning of January. Not the Malossi. It's in the same order as the backordered piston though, so it'll be awhile.
@@49ccscoot Come in now my frind , send it back and ordre the Malossi MHR team 2 ignigtion …
@@bp-tuningaeroxlc-dd6474 I use Stage6 PVL another great option for less $
I dont see why you need the 34 carb, its not a dragrace moped its your cruiser moped, you cant get everything on a tuned high end 2-stroke power and reliability is a fine straw, go for reliability and not raw power it will break
I think I should be able to use the 34mm for both. Ryan and others do it. I really think my timing curve is too aggressive down low and not aggressive enough in the powerband. Using round or oval slide carbs has made it work well enough, but both times that I've tried to switch to flat slides on my last 2 engines has ended in disaster. The rounder slides seem to be more forgiving.
but should the timing make such a difference between 28 and 34 to be night and day difference?
i hope so for you, but i don´t think thats the case.
but we hopefully will all find out 🙂@@49ccscoot
@@49ccscoot you have to remember no offense youre a big guy you always gonna have higher temps then they, and timing maby is a bit to aggressive down low
@@labrikorn_3299 It does seem odd to me as well. When I first started considering timing, I was actually thinking that maybe cylinder filling would be better with the large carb and it may need less advance... but I followed what made more sense to me and mimicked timing known to work in the powerband.
hmm will not make muck sense, but maybe check also if the membrane is still ok and can close completely. (no gap between carbon membrane and membrane housing).
also just a thought: could it be that the suction of the motor (the volume) is to low for that size carburator, with a nearly none restrictive air filter. => stupid idea explained: it could have not enough power to suck the fuel through the nozzle, rather then only air when its WOT. because it runs good at low to mid throttle when there is also more suction power, due the lower carb opening.
just thinking loud.
@@49ccscoot
🙁🙁
Smart carb next time!:)