I picked up a 2002 YZ250 in pieces. All your YZ vids have been super helpful- from the engine rebuild, lacing up black wheels and now the carb. Thanks! Keep them coming!
One thing I have run into that I have never seen on YT about the rich YZ jetting is: It takes a lot longer to warn up the coolant, riders get impatient, and take off early. With stock jetting, I am sure you would find a lot of damaged pistons running in those cylinders (Piston expands before the cold cylinder could, resulting is scuffing and worse at the exhaust port.). Get your jetting dialed in, and the coolant warms up much much faster.
Hey Chuck. Thanks for the video, but...believe it or not...Yamaha has a mistake on their chart in the YZ250 manual. The power jet actually works from about 1/2 throttle to full open. Yes, the solenoid will close the circuit at higher rpm (to allow the engine to rev cleanly to higher rpm), and while open at lower rpm will allow a richer mixture for better throttle response. If you track the carbuetor's power jet circuit you'll see it enters the venturi at the point the slide would be about half open, so it "physically" limits the flow through the circuit from that point to full open.
Different years of YZ250 manuals have different graphs for the jetting. Maybe that’s why. 🤷♂️ What I know for sure is that the difference is immediately noticeable when the power jet is changed.
Most of the later YZ's are pretty identical bikes. Mine is a 2019 YZ250, and I pretty much changed the entire bike, as it was too tall, too high of a rpm power curve, and I got rid of the Batman modern abstract art garbage plastic, (surgery and replacement). I lowered the suspension .75" and the seat 1", (wanna flat corner me now kids?),so it is about the same height as a 1985 Works Honda RC 250 that Hannah and O'Mara rode. Good enough for me. Corners great now. The engine: I wanted much more lower rpm and mid range, and knew I would be losing a bit of top end rev. Damn, I forgot to put a tach on it when stock, but it seems close for top rpm, but i can tell it is a bit softer up there when reaching the limit. you are not going to keep up with a 60 hp 450 anyway. Make the engine good for everything else. Your jetting depends on air quality and engine modifications. I live in Michigan, and that is about all I know about air quality here. 65 degrees F. for the last jetting run, nice sunny day. Good enough for me, I am not riding anywhere else. :) So I will give you all the engine mods I did, (all reversible if wanted), and the jetting that is pretty darn good that I found so far. I changed every jet, but the main jet so far, and I am going one lean (175 from a 178 stock in the USA), because the plug is a bit dark brown at full throttle still. This bike was flooded rich stock (MXA said it was good? Not the MXA I grew up with, no sir.), and I did my engine mods first. The jetting is specific to the engine mods, and my Michigan weather. Engine mods: 1) FMF Gnarley pipe for a lower rpm peak power target, (pipe tuned for lower rpm power than stock. I am guessing 500 rpm lower peak target, or a tad more.). 2) V-force reeds. For better lower rpm response. More and thinner petals open earlier at lower rpms. I am not using the stock aluminum spacer plate between the reeds and the cylinder, for higher crank case primary compression, (more of a mid range hit). 3) FMF spark arrested silencer "Turbinecore 2", but I shortened it almost 4", and packed it loosely with wall fiberglass to keep the sound down better. 4) Last, I raised the compression (need 100 octane gas) and still have a very acceptable .048" squish clearance with the stock head, lowered the exhaust port to better match the lower rpm target of the FMF pipe, (where the magic is, matching pipe with porting), and did both of those, to help low end power, by not using the cylinder base gasket, (seal it well with a great sealer that resists gasoline. Not silicone. You do not want a leak there.). Jetting: Super rich stock, and I blame the power jet. I have tuned all my carbs before the power jet since I started racing in the 80's, and I don't think it is needed, just more complications. I think my perfectly jetted 97 KX250 would still hole shot this bike, but not by much.
Pilot: Went from 50 (USA and Canada got the 50) to 48. Air screw 1.25 turns out, (and very responsive now, starts easier too, cold or hot.) Needle: First went to top groove, and still too rich. The N3CW (next leaner) needle at the top groove is a half groove leaner, have it there now. I would not want to go any leaner near the pilot rpm's, but still a tad rich as the rpm's rise. Power jet: went from the stock 50 to the only one more lean, the #40. My manual chart says it kicks in for the last half of the rpm range, and it was very rich there. Main jet: The stock jet in the USA and Canada is the 178, and it is still a bit dark at full throttle chops. The 175 may be my last jetting change that I will test on a colder day. The bike is soooooooo much more enjoyable to ride than the stock screaming sky scrapper. MXA used to complain about tall bikes too, but not today. Go find that berm boys. You can hardly turn a bike without one. :) Doug in Michigan,---happy to share the set up I finally like. Oh yea,--I don't run my handlebars in the freestyle position that took over racing either. Can't feel the corners going in. :) Oh yea. I weigh 200 lbs using the stock gearing still, (I usually gear down 2 teeth in the rear, but have not worn out this stock set yet. May not change gearing now), and the engine pulls much more starting down low, (not monster like the 97 KX250, but strong), and pulls hard and smoothly through the mid range and into a slightly softer top rpm pull. Lofting the front end over something at lower rpm's is now easy. It is a good blend of power and smoothness, with no big hit that can catch you off guard. I don't ride the muddy slippery tight wet rooty stuff, so I wont desire a flywheel weight. But it should work well with one for that stuff IMO. I hated the bike when I bought it. Now, it may be the best bike I ever had/rode. I think I will gear it down though adding 2 teeth to the rear for the drive train change, to make it a bit more 97 KX250 like. :)
Hello i have a 06 yz250 im in ohio at 850 above sea level,i have fmf fatty and shorty silencer and vforce3 reeds i ride woods and am more steady on throttle,should i run 175,45,3 clip down and 40 power jet? And i run 32:1
Great video. I bought a 2024 yz125x and had to change my main jet at the track. When I did it I had to unplug both the throttle position sensor and power jet connections so I could rotate the carb. Once I got the jet changed I completely forgot to plug the electrical connectors back in.....but the bike ran great, no over rich loading up like it had before and I rode all day. The next day during preride check I seen the connectors and rehooked them back up. And didn't notice any difference the whole day.😂 Looks like I need to get a 40 power jet too. Edit. After a little more looking into this and reading the yz125x manual doesn't even say it has a power jet, or where it effects the fueling. So even though it is the same carb with the same parts, per the manual it doesn't exist on the 125. LoL
How is everything with your 125x? I just got mine 3 weeks ago and threw in the jd jetting kit, but nobody seems to know much about this carb and bike combo
I've got a '23 YZ125 that I've had fits with the jetting for 2 years now. I finally acquired the GYTR Pro Circuit jetting kit and had to order separate main and pilot jets to match the Pro Circuit recommendations. Factory Power Jet is a 35 and switched to a 70. Y4 Needle, 165 Pilot, and 62 Main. Swapped out the Air Jet from the kit also. 2 turns out of the Air Jet and Clip position 4 on the Needle. Bike runs like it's ready to race, night and day difference. No more lean bog down low nor hesitation. Runs smoother, quieter, and faster. Running 50/50 89 octane pump gas. Very low smoke and smooth idle. Before the bike would rev so high when running out the fuel that I had to feather the kill switch to keep it from blowing my motor. The factory jetting is beyond horrible. I believe the X model is much the same other than it supposedly has a 6.5 slide .vs a 7 in the non X model. Believe me, you will personally thank me for this information.
Min 10:30: My power jet on the 2019 YZ250 is exactly opposite with it's application. Your chart shows it open below 1/2 throttle. Mine is the same pattern, but opens above 1/2 throttle and the manual says it stops flowing at 8,500 rpm to rely solely on the main jet. It floods the mid range. I could go to the next more lean needle, (at the top groove now, and still spitting oil), and my next move is to replace the #50 power jet with the only learner one available, the #40 power jet. I for one, would rather go to an older carb that does not have the power jet. I don't see a need for it. By far, the 2019 YZ250 2-stroke is the most rich running bike I ever bought new, dotting my jerseys with oil from the silencer, and on the verge of fouling the plug. MXA said it was perfect.
Thats great info Chuck. I currently have a 2023 YZ250X. The PWK38 is an amazing carb when dialed it. Recently though i have been experiencing a “surging idle” when going from WOT to idle in a quick fashion. Seems to be when the bike is very hot (not boiling over hot) in extremely tight single track. Otherwise runs exceptionally well. Have been running the same jetting for 2 seasons without issue. Fresh OEM top end 15 hours ago. And a total of 85 hours on the bike. Definitely seems like a lean surge but doesn’t do it until the bike is very hot. And also don’t have a hanging idle. If anything I’m a tad rich on the bottom end. I was thinking a possible air leak but you would think if that was the case it would consistently have the issue 🤷🏼♂️
As temps increase the demands on the fuel increase. You could solve it a few ways. You could jet it richer, keep it cooler (like with a fan) or run higher octane fuel.
I noticed the new packing you unwrap, which is to be used on your bottom pan for your PWK karbruator (approx. 5.50min into the video) when you mount the gasket, can I see it making a kind of eye? You know, it actually looks like the gasket is too big for your PWK's sump, What do you do to get the New Gasket to fit properly, and why are they mostly always too big, I ride Scooter cup and. use a Keihin PWK 28MM myself, and every single time I change the gasket, it is always a little bit too big, and does the same thing as your gasket does... Why are these gaskets always a bit too big? Really nice video you made here
Sometimes they’re too big & sometimes they’re too tight. Sometimes putting them under a heat lamp dries them out enough to shrink them down a bit. You can use a bit of CA glue to hold it in a pinch too. Just don’t use much. A tiny dab.
@@ChuckfromTrueTech , What kind of heat do you use to make rubber shrink, hehe he he ????? I don't think we have that heat in Denmark, it must be special if it can do it he he eh, , because rubber doesn't shrink from heat but it does, that's the very reason why most Tuning companies convert rubber O-rings into cylinder head gaskets for 2-stroke engines….
Thanks for the info! I have issue with mine, I set up an ok idle, after reving up it stay way high... if put in gear and slightly put load, than the idle is way to low and die. No admision leaks, played with jetting, needle, changed all sealings, etc... cant find the root cause...and is driving me crazy...
Usually one of 2 scenarios. Either the pilot is too rich & the idle screw is turned way in to make it run or the pilot is too lean and causing it to detonate.
My YZ 250 2019 power jet responds like you say. But my chart is opposite of his from the manual (min 10:30). His is open and closed before 1/2 throttle. Mine is open and closed after 1/2 throttle, and shuts off at 8,500 rpm (per the manual). That alone changes the jetting process. I would rather not have the power jet. I don't see a need for it. Just makes the bike harder to tune.
Then what is the TPS for? I never had a carb with it that does not have a power jet. But after getting all my bikes jetted perfectly before the power jet, I can't figure out what the power jet is good for either. I am sure the TPS is part of the power jet configuration. It has to be. But my I trust my wrist more for throttle position. :)
Excellent video, highly underrated TH-cam channel. Keep it up man. I’m working on my ‘98 CR250 at the moment and trying to figure out why it won’t idle. It appears to be running rich so I think I need to change the pilot jet. That being said, how many different sized power jets should I order? Just one size at a time?
I haven’t messed with the power jet on a CR, I’m not sure, but first it’s important to verify that everything else is in good shape: carb clean, reeds, piston/cylinder, crank seal, spark plug, air filter etc. Once all that checks out it’s time to change jets.
Thank you for such an excellent video. Do you run your YZ250 on trails or hard enduro? Do you think that the YZ250X is better for slow trails and hard enduro?
This YZ is a big learning project for me. I rode a YZ in trails for years and now my primary bike is a TPI. I’ve ridden this YZ in some proper hard enduro terrain, but it just can’t compare to a proper enduro bike. It’s good, but not excellent. The X is better for hard enduro, but it’s still no enduro bike.
YZ250s are track bikes. If you keep the jetting from factory and then are lugging them they will foul plugs. If you want to putt around on trails, before you swap to an 18'' rear wheel or anything else determine what oil you are going to use, what ratio, and then rejet.
In my 23 YZ250x manual the Power jet shows to come on 1/2 to full throttle. What gives? Different on the X or did Yamaha change the function? Same diagram just shows just moved over to the right...
Did a little digging, I could only find the pic u showed back in the old manuals like 03. Does the power jet run on vacuum and the solenoid just shuts it off?
You forgot to let people know that you should be changing the JET BLOCK oring gasket if people are having idle issues or fouling plugs on decel / less than 1/4 throttle. I'd replace that Jet block gasket after using an ultra sonic cleaner on it...
Do you change power jet without downsizing pilot and main? I’ve downsized my pilot and main 2 sizes for my style and elevation but I wasn’t sure if changing power jet is gonna lean it out too much. I’m barely on the pipe most rides, not smoking, no spooge and plug is still black, not chocolate brown.. 2021 yz250 with 3hrs on it. Single track and trails
Yes. You can change it independent of the rest of the jets. If you’ve gone sown 2 sizes on pilot & main it’s very likely that your needle is too rich as well. You must be up at elevation to be making those changes?
@@ChuckfromTrueTech I installed the next needle size down (n3cw-2) along with jets. I’m at 400ft and ride from sea-level to 2500ft, probably 1200ft more often then 2500ft. I’m old, I ride slow and much prefer the mx style bike over “trail” bike, just cause of the way I ride and I like a stiffer suspension. Before I changed jets, I would come out of a corner on a trail… hit the throttle and it would foul the plug everytime. Tried needle first, but still spoogey and fouling… that why I went with the “drastic” changes. I just got my #40 power jet in the mail yesterday. Should I swap power jet and put stock needle and jets back in?
Quick question for the 2 stroke keihin portion.. between the needle clip and cable holder is that a spring and rubber gasket? My carb seems to be missing any parts on the inside of the cable holder??
The Suzuki needle is a triple taper instead of dual. It tends to give a smoother feel in the bottom to mid-range. It’s not for everyone, but I like it.
I've got a 2023 YZ250, just put the FMF exhaust on it. Jetted it to 175/48 (FMF specs) Still drips at the pipe/silencer connection and out the tail pipe. I am running 927 premix 30:1, I am wondering if I need to go to 40:1. or maybe the bike is just not broken in yet, its got 5 hours on it.
Unless you’re an aggressive motocross racer 30:1 is too rich, but spooge is almost always caused by a fuel rich (as opposed to oil rich) mixture. Every bike & every rider is different. The FMF chart can be a good starting point but you will need to tune the bike by riding it in your actual riding environment. It certainly sounds like you’re too fuel rich as well.
Thanks for the reply. I’m trying to learn how to get this thing tuned. Do you think going to 40:1 would cause less of the spooge build up, or should I try adjusting jets again? I’m def a weekend warrior riding small motocross tracks in Florida at sea level.
I don’t expect reducing the oil will affect the spooge. Reducing fuel usually does. Have a look at that YZ jetting chart in the manual & go through the instructions. They’re better than the FMF recommendations.
Thanks, I found the chart in the catalog, it appears my new jetting is leaner than stock, but I think my oil may be the problem. I'm using Maxima 927 which has a very high flash point 420 (almost double of Yamalube-255) and from what I read you really have to hammer that throttle and ring the bike out, which I'm def not riding hard enough. For starters I am going to go to a regular premix like the Yamalube or HP2.
Thanks for the info! I also just picked up a 2024 YZ125 and I've noticed that when I turn the gas off and let the fuel run out of the carb, just before it turns off, it revs really high and the RPM's shoot way up before shutting off, my YZ250 does this a hair, but not as high on the RPM's. It's brand new and starts on the first kick, doesn't drip and pulls like a monster for a little 125. It came with the V-Force 4 system from Yamaha. I assume it's due to getting air but slowly starving of fuel since it happens right before it runs completely out. Any reason to be overly worried about this?@@ChuckfromTrueTech
One big reason why so many people do not know much about jetting a carb,---------------------------------is because MXA does not know how to do it anymore.
Hey chuck , so when you set the float Hight you say you want the float arm to just touch the needle without comprising it , mine compresses it like halfway in so I have to bend it quite a bit to do as you said, I'm just not confident yet brand new bike and it came like that but not running very well, how would it affect the bike if the pin is being compressed halfway in instead of just touching it ??
The float will close the valve as soon as it presses the needle against the seat. Measuring halfway compressed isn’t accurate. Your float will close the valve too early resulting in a low fuel level. The bike may run lean.
@@ChuckfromTrueTech thanks for answering so quickly, I will reassess the float Hight I'm sure it's way out , but the only thing is the bike was using alot of fuel and seemed to be running rich , so I jetted down the main and pilot and the power Jet to a 40 for the yz250 like you did in your video but I didn't change the needle position and the bike felt much better but I think I need to change the needle to a richer position as the bike is lacking top end pull , I'm just wondering if the float Hight is way out that means my jetting will need redoing yea ?
@@zackiaryruddick701I saw in another video that you hold the carb at a 60 degree angle to measure float height. It was for a Beta, but with the same carb. I think that they want it at an angle so the weight of the float doesnt compress the needle.
@ChuckfromTrueTech I have searched everywhere trying buy a powerjet for 05 kx250 and can't find it anywhere I was wondering if you have heard if the yz and kx powerjet are compatible
I think we benefit with out the power jet. I have tuned may 2-stroke carbs before this thing, and all of them were easier to get running well than this added confusion.
I've been running 32.1 on my 23 yz 250 x. Is that too heavy and will i sustain damage by running it at that? Everything is completely stock. Only 3 hours on the bike. 87 non ethanol fuel and yamalube.
You definitely need to run at least a 90 octane fuel. That’s what the manual on my 2006 calls for. 93 would be better. No need for “Race” fuels if the bike is mostly stock
You better go to 93 octane fuel. I was using 90 REC fuel in rural Michigan (90 octane with no alky), and I suffered some detonation damage. That is on a 2019 YZ250, and they lowered the compression around 2011. That is not your piston slapping at low rpms when you get on the gas. That is detonation. I lowered my cylinder by not using a cylinder base gasket (raises compression, port time better matches the lower rpm target FMF Gnarley pipe,. and still has ,048" squish clearance (about .030" is min for a 125., .040" for a 250), and it now requires 100 octane (I mix the 90 with 110 race gas now, 50/50). The higher compression will also lean the jetting because it burns hotter, (and I still have to lean the carb out tons), but I get a much better boost in the lower rpm's from that higher revving 250 engine. I screwed up and did not measure top rpm with a tach when it was stock. But I can't tell if I lost top speed/rpm, so it has to be close. I know guys who tests oil on very high revving 30cc race 2-stroke engines, and they are pretty sharp guys (Quick Draw marine boat RC race engines in Northern Cal.). Their 2 favorite oils I think still are, the Motul Kart GP 2-t oil (expensive), and the Klotz Supertechniplate Castor/syn blend. They found the best lubricity from those running 1/2 hr. on a dyno full throttle dragged down to 16,000 rpm. That is some serious 'durability testing". :)
"They found the best lubricity from those running 1/2 hr. on a dyno full throttle dragged down to 16,000 rpm. That is some serious 'durability testing". :)" 16,000 rpm on that engine of theirs is peak HP between 8-8.5hp, (and it is held there wide open for 1/2 hr.) Not bad for 30cc's. :)
That depends on your engine, air filter, pipe, fuel & riding style. I completely changed it after test riding the bike. The 40 power jet is the only part I kept.
"What altitude and temperature would you say the jetting on this carb is ideal for?" His. lol You can pick up a hand held air quality devise to know temp, density and humidity if you want to take notes. :)
Hoping u can help me. 2023 yz125 jetting is trash stock. Pilot is close at 62 I could go down to a 60 or 58. Main is 165 which is also close I could go up a little and play with it. I have a horrible bottom end bog, you snap the throttle without the clutch and it wants to die. I’ve went to the richer needle on the bottom clip and it is almost there. Everything I’ve seen and read everyone is going leaner, but I’m thinking richer on the needle since it’s getting better the farther I go down on the clip. So should I jump up to the next thinner needle, meaning smaller diameter in the straight portion with the same taper starting position. Or should I chase it up with the taper position. There is only 1 richer with the position difference so nydf to nycf which is only a 1/2 groove richer. The needle I’m thinking of going to is nyde which would be same taper start position but 1 step richer on the straight portion. Which by the graph I have in my manual controls closed to 1/4 throttle. I know pro circuit has a y3 needle which they say cleans up the mid but they still don’t have it in stock, and I can’t find it anywhere. There is a y4 needle but they also said they’re still testing with that one. I got the jd jetting kit but it’s way off 50 pilot and I have a half to 3/4 turn on the pilot and it just sounds lean down low. Their main is at 175 and to me seems way too big, and the needles make the bog worse than before. Only other thing I can think is the mid body gasket but the carb is new, but doesn’t mean it’s not bad. Or the power jet but in my manual it says under 8500 to the extent of 1/2 to full. Any help would be appreciated thanks.
That’s a lot of info. It sounds to me like you’re stuck in a vortex to too much information. It sounds to me like your pilot isn’t sorted out yet. I expect that with everything stock, if you go up a little on the pilot you may get closer to a diagnosis. Most bogs like the one you’re describing are caused by the pilot.
@@ChuckfromTrueTech it doesn’t bog off idle when I snap the throttle in neutral. It’s under load when in gear. I had a 50 pilot in it and it was lean bogging snapping the throttle in neutral. Air screw was 1/2 turn out. The bigger pilot fixed that, if I go any bigger you loose the air screw tuning. Meaning a pilot over 62 and I’m 3 turns out and it’s a burbling mess. 🤷🏼♂️
My 2024 yz125x likes a 52 pilot, 172 main. Stock needle on top clip position. The bikes come to rich down low, to lean up top. This power jet talked about in the video is probably another cause of so rich down low, so if you change the power jet like described you might have to go richer on pilot since your leaning out the power jet.
@@MS-ye9vx I started in the 3rd clip position, but I'm down to the 2nd and I'm going to go another half a position. I never trust any jetting charts. Every bike is a little different.
I use water & about a litre (quart) of Zoom Motorcycle Cleaner. It does a good job with aluminum parts & getting dirt stains off, but not great with anything greasy. It works well for me because I generally degrease in my varsol tank first.
I never experiment with them because it’s tough to find good info on them and the JD kits are over-priced if you just want the parts. I don’t need a kit. I have all the individual parts, so I just make the exact change I need.
@@ChuckfromTrueTech I say generally, if you are spitting oil in the mid range, the power jet is the first thing to go smaller on. I would like to see a vid on how to remove it. I never spent so much time jetting a carb to run perfectly, before this gimmick (IMO).
There are too many variables to be able to say what jetting you need. Each bikes is a little different. If the engine is in good shape you should be very close to stock. If you’re struggling it’s often helpful to go back to stock and make small changes from there. Jetting charts are often way off.
The air screw, and pilot jet handle the jetting from idle to about 1/8th throttle opening, and I would bet you are riding with more throttle than that. You were probably fouling plugs,---where the power jet kicks in.
the generic piece of paper he shows you starts at about 10:27 and is about a minute long and not game changing. Who wants to watch another carb cleaning video?
That "generic piece of paper" is from the owners manual. But I see a mistake on that too, (says the P-Jet shuts off at 8,500 rpm, and clearly shut off at 1/2 throttle. My 2019 manual says the same thing, but the P-Jet does not even open until 1/2 throttle. I am not a fan of the power jet.
Best Kehin carb vid on the entire interwebs. Thanks TrueTech.
but that not what he said it was. super annoying
I picked up a 2002 YZ250 in pieces. All your YZ vids have been super helpful- from the engine rebuild, lacing up black wheels and now the carb. Thanks! Keep them coming!
One thing I have run into that I have never seen on YT about the rich YZ jetting is: It takes a lot longer to warn up the coolant, riders get impatient, and take off early. With stock jetting, I am sure you would find a lot of damaged pistons running in those cylinders (Piston expands before the cold cylinder could, resulting is scuffing and worse at the exhaust port.). Get your jetting dialed in, and the coolant warms up much much faster.
Hey Chuck. Thanks for the video, but...believe it or not...Yamaha has a mistake on their chart in the YZ250 manual. The power jet actually works from about 1/2 throttle to full open. Yes, the solenoid will close the circuit at higher rpm (to allow the engine to rev cleanly to higher rpm), and while open at lower rpm will allow a richer mixture for better throttle response. If you track the carbuetor's power jet circuit you'll see it enters the venturi at the point the slide would be about half open, so it "physically" limits the flow through the circuit from that point to full open.
Different years of YZ250 manuals have different graphs for the jetting. Maybe that’s why. 🤷♂️ What I know for sure is that the difference is immediately noticeable when the power jet is changed.
Most of the later YZ's are pretty identical bikes. Mine is a 2019 YZ250, and I pretty much changed the entire bike, as it was too tall, too high of a rpm power curve, and I got rid of the Batman modern abstract art garbage plastic, (surgery and replacement). I lowered the suspension .75" and the seat 1", (wanna flat corner me now kids?),so it is about the same height as a 1985 Works Honda RC 250 that Hannah and O'Mara rode. Good enough for me. Corners great now.
The engine: I wanted much more lower rpm and mid range, and knew I would be losing a bit of top end rev. Damn, I forgot to put a tach on it when stock, but it seems close for top rpm, but i can tell it is a bit softer up there when reaching the limit. you are not going to keep up with a 60 hp 450 anyway. Make the engine good for everything else. Your jetting depends on air quality and engine modifications. I live in Michigan, and that is about all I know about air quality here. 65 degrees F. for the last jetting run, nice sunny day. Good enough for me, I am not riding anywhere else. :) So I will give you all the engine mods I did, (all reversible if wanted), and the jetting that is pretty darn good that I found so far. I changed every jet, but the main jet so far, and I am going one lean (175 from a 178 stock in the USA), because the plug is a bit dark brown at full throttle still.
This bike was flooded rich stock (MXA said it was good? Not the MXA I grew up with, no sir.), and I did my engine mods first. The jetting is specific to the engine mods, and my Michigan weather.
Engine mods:
1) FMF Gnarley pipe for a lower rpm peak power target, (pipe tuned for lower rpm power than stock. I am guessing 500 rpm lower peak target, or a tad more.).
2) V-force reeds. For better lower rpm response. More and thinner petals open earlier at lower rpms. I am not using the stock aluminum spacer plate between the reeds and the cylinder, for higher crank case primary compression, (more of a mid range hit).
3) FMF spark arrested silencer "Turbinecore 2", but I shortened it almost 4", and packed it loosely with wall fiberglass to keep the sound down better.
4) Last, I raised the compression (need 100 octane gas) and still have a very acceptable .048" squish clearance with the stock head, lowered the exhaust port to better match the lower rpm target of the FMF pipe, (where the magic is, matching pipe with porting), and did both of those, to help low end power, by not using the cylinder base gasket, (seal it well with a great sealer that resists gasoline. Not silicone. You do not want a leak there.).
Jetting: Super rich stock, and I blame the power jet. I have tuned all my carbs before the power jet since I started racing in the 80's, and I don't think it is needed, just more complications. I think my perfectly jetted 97 KX250 would still hole shot this bike, but not by much.
Pilot: Went from 50 (USA and Canada got the 50) to 48. Air screw 1.25 turns out, (and very responsive now, starts easier too, cold or hot.)
Needle: First went to top groove, and still too rich. The N3CW (next leaner) needle at the top groove is a half groove leaner, have it there now. I would not want to go any leaner near
the pilot rpm's, but still a tad rich as the rpm's rise.
Power jet: went from the stock 50 to the only one more lean, the #40. My manual chart says it kicks in for the last half of the rpm range, and it was very rich there.
Main jet: The stock jet in the USA and Canada is the 178, and it is still a bit dark at full throttle chops. The 175 may be my last jetting change that I will test on a colder day.
The bike is soooooooo much more enjoyable to ride than the stock screaming sky scrapper. MXA used to complain about tall bikes too, but not today. Go find that berm boys. You can hardly turn a bike without one. :)
Doug in Michigan,---happy to share the set up I finally like. Oh yea,--I don't run my handlebars in the freestyle position that took over racing either. Can't feel the corners going in. :)
Oh yea. I weigh 200 lbs using the stock gearing still, (I usually gear down 2 teeth in the rear, but have not worn out this stock set yet. May not change gearing now), and the engine pulls much more starting down low, (not monster like the 97 KX250, but strong), and pulls hard and smoothly through the mid range and into a slightly softer top rpm pull. Lofting the front end over something at lower rpm's is now easy. It is a good blend of power and smoothness, with no big hit that can catch you off guard. I don't ride the muddy slippery tight wet rooty stuff, so I wont desire a flywheel weight. But it should work well with one for that stuff IMO.
I hated the bike when I bought it. Now, it may be the best bike I ever had/rode. I think I will gear it down though adding 2 teeth to the rear for the drive train change, to make it a bit more 97 KX250 like. :)
Hello i have a 06 yz250 im in ohio at 850 above sea level,i have fmf fatty and shorty silencer and vforce3 reeds i ride woods and am more steady on throttle,should i run 175,45,3 clip down and 40 power jet? And i run 32:1
What is your go to premix and ratio? Awesome video and very helpful!
I run 50:1, but I ride mostly technical rocks. Primarily low RPM. For higher RPM riding I would be mixing richer.
Great video. I bought a 2024 yz125x and had to change my main jet at the track. When I did it I had to unplug both the throttle position sensor and power jet connections so I could rotate the carb. Once I got the jet changed I completely forgot to plug the electrical connectors back in.....but the bike ran great, no over rich loading up like it had before and I rode all day.
The next day during preride check I seen the connectors and rehooked them back up. And didn't notice any difference the whole day.😂
Looks like I need to get a 40 power jet too.
Edit. After a little more looking into this and reading the yz125x manual doesn't even say it has a power jet, or where it effects the fueling. So even though it is the same carb with the same parts, per the manual it doesn't exist on the 125. LoL
How is everything with your 125x? I just got mine 3 weeks ago and threw in the jd jetting kit, but nobody seems to know much about this carb and bike combo
@ericmahoney5916 I have a couple videos on my channel about jetting it and now she runs like a champ.👍
I've got a '23 YZ125 that I've had fits with the jetting for 2 years now. I finally acquired the GYTR Pro Circuit jetting kit and had to order separate main and pilot jets to match the Pro Circuit recommendations. Factory Power Jet is a 35 and switched to a 70. Y4 Needle, 165 Pilot, and 62 Main. Swapped out the Air Jet from the kit also. 2 turns out of the Air Jet and Clip position 4 on the Needle. Bike runs like it's ready to race, night and day difference. No more lean bog down low nor hesitation. Runs smoother, quieter, and faster. Running 50/50 89 octane pump gas. Very low smoke and smooth idle. Before the bike would rev so high when running out the fuel that I had to feather the kill switch to keep it from blowing my motor. The factory jetting is beyond horrible. I believe the X model is much the same other than it supposedly has a 6.5 slide .vs a 7 in the non X model. Believe me, you will personally thank me for this information.
@@ericmahoney5916I've read in some forums that the JD jetting is just as shitty as the factory jetting.
Min 10:30: My power jet on the 2019 YZ250 is exactly opposite with it's application. Your chart shows it open below 1/2 throttle. Mine is the same pattern, but opens above 1/2 throttle and the manual says it stops flowing at 8,500 rpm to rely solely on the main jet. It floods the mid range. I could go to the next more lean needle, (at the top groove now, and still spitting oil), and my next move is to replace the #50 power jet with the only learner one available, the #40 power jet. I for one, would rather go to an older carb that does not have the power jet. I don't see a need for it. By far, the 2019 YZ250 2-stroke is the most rich running bike I ever bought new, dotting my jerseys with oil from the silencer, and on the verge of fouling the plug. MXA said it was perfect.
Different years use different power jet settings. They all operate in the mid range.
Great informative video! What brand/source breather line do you use?
Earned a Sub. 👍🏻
I buy it through a wholesale supplier I deal with. Not sure of the brand. I buy it in a large roll.
Thats great info Chuck. I currently have a 2023 YZ250X. The PWK38 is an amazing carb when dialed it. Recently though i have been experiencing a “surging idle” when going from WOT to idle in a quick fashion. Seems to be when the bike is very hot (not boiling over hot) in extremely tight single track. Otherwise runs exceptionally well. Have been running the same jetting for 2 seasons without issue. Fresh OEM top end 15 hours ago. And a total of 85 hours on the bike. Definitely seems like a lean surge but doesn’t do it until the bike is very hot. And also don’t have a hanging idle. If anything I’m a tad rich on the bottom end. I was thinking a possible air leak but you would think if that was the case it would consistently have the issue 🤷🏼♂️
As temps increase the demands on the fuel increase. You could solve it a few ways. You could jet it richer, keep it cooler (like with a fan) or run higher octane fuel.
@@ChuckfromTrueTech Thank you for the input I greatly appreciate it!
@@ChuckfromTrueTech The is true. The hotter an engine gets and the more load it has to endure, the more fuel it requires.
I take it TANGO stands for T and FOX TROT stands for FT in the power jet part#?..thank you for the video I definitely need to change my power jet
I noticed the new packing you unwrap, which is to be used on your bottom pan for your PWK karbruator (approx. 5.50min into the video)
when you mount the gasket, can I see it making a kind of eye? You know, it actually looks like the gasket is too big for your PWK's sump,
What do you do to get the New Gasket to fit properly, and why are they mostly always too big, I ride Scooter cup and. use a Keihin PWK 28MM myself, and every single time I change the gasket, it is always a little bit too big, and does the same thing as your gasket does...
Why are these gaskets always a bit too big?
Really nice video you made here
Sometimes they’re too big & sometimes they’re too tight. Sometimes putting them under a heat lamp dries them out enough to shrink them down a bit. You can use a bit of CA glue to hold it in a pinch too. Just don’t use much. A tiny dab.
@@ChuckfromTrueTech , What kind of heat do you use to make rubber shrink, hehe he he ????? I don't think we have that heat in Denmark, it must be special if it can do it he he eh,
, because rubber doesn't shrink from heat but it does, that's the very reason why most Tuning companies convert rubber O-rings into cylinder head gaskets for 2-stroke engines….
Best carb video ever made!
Thanks for the info! I have issue with mine, I set up an ok idle, after reving up it stay way high... if put in gear and slightly put load, than the idle is way to low and die. No admision leaks, played with jetting, needle, changed all sealings, etc... cant find the root cause...and is driving me crazy...
Usually one of 2 scenarios. Either the pilot is too rich & the idle screw is turned way in to make it run or the pilot is too lean and causing it to detonate.
The tps doesn't control the power jet solenoid in any way. The ecu triggers it and it is rpm based. Solenoid closes off the power jet at 8500 rpm.
My YZ 250 2019 power jet responds like you say. But my chart is opposite of his from the manual (min 10:30). His is open and closed before 1/2 throttle. Mine is open and closed after 1/2 throttle, and shuts off at 8,500 rpm (per the manual). That alone changes the jetting process. I would rather not have the power jet. I don't see a need for it. Just makes the bike harder to tune.
Then what is the TPS for? I never had a carb with it that does not have a power jet. But after getting all my bikes jetted perfectly before the power jet, I can't figure out what the power jet is good for either. I am sure the TPS is part of the power jet configuration. It has to be. But my I trust my wrist more for throttle position. :)
Bravo!! One of, if not the best video on this subject that exists
Excellent video, highly underrated TH-cam channel. Keep it up man. I’m working on my ‘98 CR250 at the moment and trying to figure out why it won’t idle. It appears to be running rich so I think I need to change the pilot jet. That being said, how many different sized power jets should I order? Just one size at a time?
I haven’t messed with the power jet on a CR, I’m not sure, but first it’s important to verify that everything else is in good shape: carb clean, reeds, piston/cylinder, crank seal, spark plug, air filter etc. Once all that checks out it’s time to change jets.
Thank you! Really appreciate you talking thrrough what you're doing, other videos jsut have some timnelapse with music which helps me Zero.
I know this is an old video but what solvent cleaner do you use in the ultrasonic cleaner, carb came out looking fantastic!
That was Zoom cleaner. It cleans dirt off aluminum, but no good for fuel residue.
Thank you for such an excellent video. Do you run your YZ250 on trails or hard enduro? Do you think that the YZ250X is better for slow trails and hard enduro?
This YZ is a big learning project for me. I rode a YZ in trails for years and now my primary bike is a TPI. I’ve ridden this YZ in some proper hard enduro terrain, but it just can’t compare to a proper enduro bike. It’s good, but not excellent. The X is better for hard enduro, but it’s still no enduro bike.
@@ChuckfromTrueTech thank you, I really appreciate your perspective.
YZ250s are track bikes. If you keep the jetting from factory and then are lugging them they will foul plugs. If you want to putt around on trails, before you swap to an 18'' rear wheel or anything else determine what oil you are going to use, what ratio, and then rejet.
My yz250x does the same thing. Changed power jet all good now
Awesome video, where can I find that carb cleaner at? Can’t seem to find it thanks
Suzuki has discontinued it but Yamaha & Honda still offer it.
Is the Yamaha combustion chamber cleaner the same thing that’s the only thing I can find.
In my 23 YZ250x manual the Power jet shows to come on 1/2 to full throttle. What gives? Different on the X or did Yamaha change the function? Same diagram just shows just moved over to the right...
Different years have it set different.
Did a little digging, I could only find the pic u showed back in the old manuals like 03. Does the power jet run on vacuum and the solenoid just shuts it off?
What is the name of the catchy little tune, I don’t normally like music over a tutorial but this one’s cool .
🤷♂️ It was from some copyright-free website. Thought it fit the bill.
@@ChuckfromTrueTech I know the name of that tune. It is called "distraction". :)
You forgot to let people know that you should be changing the JET BLOCK oring gasket if people are having idle issues or fouling plugs on decel / less than 1/4 throttle.
I'd replace that Jet block gasket after using an ultra sonic cleaner on it...
I’ve never had one fail. 🤷♂️
Do you change power jet without downsizing pilot and main? I’ve downsized my pilot and main 2 sizes for my style and elevation but I wasn’t sure if changing power jet is gonna lean it out too much. I’m barely on the pipe most rides, not smoking, no spooge and plug is still black, not chocolate brown.. 2021 yz250 with 3hrs on it. Single track and trails
Yes. You can change it independent of the rest of the jets.
If you’ve gone sown 2 sizes on pilot & main it’s very likely that your needle is too rich as well.
You must be up at elevation to be making those changes?
@@ChuckfromTrueTech I installed the next needle size down (n3cw-2) along with jets. I’m at 400ft and ride from sea-level to 2500ft, probably 1200ft more often then 2500ft. I’m old, I ride slow and much prefer the mx style bike over “trail” bike, just cause of the way I ride and I like a stiffer suspension. Before I changed jets, I would come out of a corner on a trail… hit the throttle and it would foul the plug everytime. Tried needle first, but still spoogey and fouling… that why I went with the “drastic” changes. I just got my #40 power jet in the mail yesterday. Should I swap power jet and put stock needle and jets back in?
#172 main #45 pilot
@@ShortBusEndurowould be better to go back up to 175, check new plug and look for brown chocolate tip and if not 172 is your way to go.
@@ShortBusEnduroI'd mirror the Pro Circuit jetting specs with the Pro Circuit GYTR jetting kit.
Quick question for the 2 stroke keihin portion.. between the needle clip and cable holder is that a spring and rubber gasket? My carb seems to be missing any parts on the inside of the cable holder??
Some PWK carbs have the spring & some don’t. I’m not sure what the reason is, but most KTM & Beta carbs don’t have it.
Chuck,
Where do you buy your bulk carb hose?
Winners’ Circle or Thibault.
Two questions:
Why go to a 40 power jet?
And what’s so special about using a Suzuki needle in these carbs?
Wait, just got the the end of your video, I see you changed the power Jett because it was too rich.
But why the Suzuki needle?
The Suzuki needle is a triple taper instead of dual. It tends to give a smoother feel in the bottom to mid-range. It’s not for everyone, but I like it.
@@ChuckfromTrueTech I see. I’ve heard people talk about it on the YZ250 Facebook page I’m a part of and I’ve always wondered.
What do you think about removing the jet block on that PWK, and renewing the o-ring?
Never done one. 🤷♂️
Good idea of course. Inexpensive o-rings. They are known as they get older to leak. Good idea of course. :)
Nice idea but what is your elevation?
Personally I ride from sea level to 8000 feet regularly, but if you’re higher you might want a smaller power jet.
Yeah I'm at only 850 ft rarely go much higher
Is the power jet size marked on the jet like the main/pilot. I haven’t got a screwdriver small enough to check the size 🤦♂️
Yep. There’s a little Keihin symbol and the size.
@@ChuckfromTrueTech thank you for the reply 👍
Will the ultrasonic cleaner not hurt the electronics
Nope.
I'm at high elevation what elevation are you at....
I ride between 1000 & 8000’. Doesn’t matter though. My specs are different due to engine setup.
I've got a 2023 YZ250, just put the FMF exhaust on it. Jetted it to 175/48 (FMF specs) Still drips at the pipe/silencer connection and out the tail pipe. I am running 927 premix 30:1, I am wondering if I need to go to 40:1. or maybe the bike is just not broken in yet, its got 5 hours on it.
Unless you’re an aggressive motocross racer 30:1 is too rich, but spooge is almost always caused by a fuel rich (as opposed to oil rich) mixture. Every bike & every rider is different. The FMF chart can be a good starting point but you will need to tune the bike by riding it in your actual riding environment. It certainly sounds like you’re too fuel rich as well.
Thanks for the reply. I’m trying to learn how to get this thing tuned. Do you think going to 40:1 would cause less of the spooge build up, or should I try adjusting jets again? I’m def a weekend warrior riding small motocross tracks in Florida at sea level.
I don’t expect reducing the oil will affect the spooge. Reducing fuel usually does. Have a look at that YZ jetting chart in the manual & go through the instructions. They’re better than the FMF recommendations.
Thanks, I found the chart in the catalog, it appears my new jetting is leaner than stock, but I think my oil may be the problem. I'm using Maxima 927 which has a very high flash point 420 (almost double of Yamalube-255) and from what I read you really have to hammer that throttle and ring the bike out, which I'm def not riding hard enough. For starters I am going to go to a regular premix like the Yamalube or HP2.
Thanks for the info! I also just picked up a 2024 YZ125 and I've noticed that when I turn the gas off and let the fuel run out of the carb, just before it turns off, it revs really high and the RPM's shoot way up before shutting off, my YZ250 does this a hair, but not as high on the RPM's. It's brand new and starts on the first kick, doesn't drip and pulls like a monster for a little 125. It came with the V-Force 4 system from Yamaha. I assume it's due to getting air but slowly starving of fuel since it happens right before it runs completely out. Any reason to be overly worried about this?@@ChuckfromTrueTech
One big reason why so many people do not know much about jetting a carb,---------------------------------is because MXA does not know how to do it anymore.
Thank you sir, very informative
Hey chuck , so when you set the float Hight you say you want the float arm to just touch the needle without comprising it , mine compresses it like halfway in so I have to bend it quite a bit to do as you said, I'm just not confident yet brand new bike and it came like that but not running very well, how would it affect the bike if the pin is being compressed halfway in instead of just touching it ??
The float will close the valve as soon as it presses the needle against the seat. Measuring halfway compressed isn’t accurate. Your float will close the valve too early resulting in a low fuel level. The bike may run lean.
@@ChuckfromTrueTech thanks for answering so quickly, I will reassess the float Hight I'm sure it's way out , but the only thing is the bike was using alot of fuel and seemed to be running rich , so I jetted down the main and pilot and the power Jet to a 40 for the yz250 like you did in your video but I didn't change the needle position and the bike felt much better but I think I need to change the needle to a richer position as the bike is lacking top end pull , I'm just wondering if the float Hight is way out that means my jetting will need redoing yea ?
@@zackiaryruddick701I saw in another video that you hold the carb at a 60 degree angle to measure float height. It was for a Beta, but with the same carb. I think that they want it at an angle so the weight of the float doesnt compress the needle.
Does the power jet only apply to yz250s or can other PWK carbs on other bikes benefit from changing the power jet?
I haven’t experimented but I have heard of guys changing it on other bikes as well. Most recently the KX250.
@ChuckfromTrueTech I have searched everywhere trying buy a powerjet for 05 kx250 and can't find it anywhere I was wondering if you have heard if the yz and kx powerjet are compatible
I think we benefit with out the power jet. I have tuned may 2-stroke carbs before this thing, and all of them were easier to get running well than this added confusion.
Any Keihin PWK carb with a Power Jet will definitely benefit.
What years of YZ250 does this apply to? I've got a 96'
‘96 didn’t have it. Looks like it started in ‘99/‘00. The rest of the carb is similar to tune.
I've been running 32.1 on my 23 yz 250 x. Is that too heavy and will i sustain damage by running it at that? Everything is completely stock. Only 3 hours on the bike. 87 non ethanol fuel and yamalube.
You won’t hurt anything with 32:1.
You definitely need to run at least a 90 octane fuel. That’s what the manual on my 2006 calls for. 93 would be better. No need for “Race” fuels if the bike is mostly stock
You better go to 93 octane fuel. I was using 90 REC fuel in rural Michigan (90 octane with no alky), and I suffered some detonation damage. That is on a 2019 YZ250, and they lowered the compression around 2011. That is not your piston slapping at low rpms when you get on the gas. That is detonation. I lowered my cylinder by not using a cylinder base gasket (raises compression, port time better matches the lower rpm target FMF Gnarley pipe,. and still has ,048" squish clearance (about .030" is min for a 125., .040" for a 250), and it now requires 100 octane (I mix the 90 with 110 race gas now, 50/50). The higher compression will also lean the jetting because it burns hotter, (and I still have to lean the carb out tons), but I get a much better boost in the lower rpm's from that higher revving 250 engine. I screwed up and did not measure top rpm with a tach when it was stock. But I can't tell if I lost top speed/rpm, so it has to be close. I know guys who tests oil on very high revving 30cc race 2-stroke engines, and they are pretty sharp guys (Quick Draw marine boat RC race engines in Northern Cal.). Their 2 favorite oils I think still are, the Motul Kart GP 2-t oil (expensive), and the Klotz Supertechniplate Castor/syn blend. They found the best lubricity from those running 1/2 hr. on a dyno full throttle dragged down to 16,000 rpm. That is some serious 'durability testing". :)
"They found the best lubricity from those running 1/2 hr. on a dyno full throttle dragged down to 16,000 rpm. That is some serious 'durability testing". :)"
16,000 rpm on that engine of theirs is peak HP between 8-8.5hp, (and it is held there wide open for 1/2 hr.) Not bad for 30cc's. :)
What altitude and temperature would you say the jetting on this carb is ideal for?
That depends on your engine, air filter, pipe, fuel & riding style. I completely changed it after test riding the bike. The 40 power jet is the only part I kept.
"What altitude and temperature would you say the jetting on this carb is ideal for?"
His. lol You can pick up a hand held air quality devise to know temp, density and humidity if you want to take notes. :)
Hoping u can help me. 2023 yz125 jetting is trash stock. Pilot is close at 62 I could go down to a 60 or 58. Main is 165 which is also close I could go up a little and play with it. I have a horrible bottom end bog, you snap the throttle without the clutch and it wants to die. I’ve went to the richer needle on the bottom clip and it is almost there. Everything I’ve seen and read everyone is going leaner, but I’m thinking richer on the needle since it’s getting better the farther I go down on the clip. So should I jump up to the next thinner needle, meaning smaller diameter in the straight portion with the same taper starting position. Or should I chase it up with the taper position. There is only 1 richer with the position difference so nydf to nycf which is only a 1/2 groove richer. The needle I’m thinking of going to is nyde which would be same taper start position but 1 step richer on the straight portion. Which by the graph I have in my manual controls closed to 1/4 throttle.
I know pro circuit has a y3 needle which they say cleans up the mid but they still don’t have it in stock, and I can’t find it anywhere. There is a y4 needle but they also said they’re still testing with that one. I got the jd jetting kit but it’s way off 50 pilot and I have a half to 3/4 turn on the pilot and it just sounds lean down low. Their main is at 175 and to me seems way too big, and the needles make the bog worse than before. Only other thing I can think is the mid body gasket but the carb is new, but doesn’t mean it’s not bad. Or the power jet but in my manual it says under 8500 to the extent of 1/2 to full. Any help would be appreciated thanks.
That’s a lot of info. It sounds to me like you’re stuck in a vortex to too much information. It sounds to me like your pilot isn’t sorted out yet. I expect that with everything stock, if you go up a little on the pilot you may get closer to a diagnosis.
Most bogs like the one you’re describing are caused by the pilot.
@@ChuckfromTrueTech it doesn’t bog off idle when I snap the throttle in neutral. It’s under load when in gear.
I had a 50 pilot in it and it was lean bogging snapping the throttle in neutral. Air screw was 1/2 turn out. The bigger pilot fixed that, if I go any bigger you loose the air screw tuning. Meaning a pilot over 62 and I’m 3 turns out and it’s a burbling mess. 🤷🏼♂️
My 2024 yz125x likes a 52 pilot, 172 main. Stock needle on top clip position. The bikes come to rich down low, to lean up top. This power jet talked about in the video is probably another cause of so rich down low, so if you change the power jet like described you might have to go richer on pilot since your leaning out the power jet.
@@Randy_Cox what is the stock needle?
@SoCalMisfit712 NYCF is stock needle for 2024 yz125x
I was wondering my manuel says power jet kick in a 1/2. Throttle
Different years activate at different times.
If you use the Suzuki 3 taper needle necj like you mention do you change any of the other jetting?
And what clip position on the necj do you start at? I’m a New York woods rider. I’ve been reading a lot in forums also. Awesome video thanks!
Yes. Since the needle is thinner at the end you need to use a smaller main. I think I ended up at a 160 on the YZ.
@@MS-ye9vx I started in the 3rd clip position, but I'm down to the 2nd and I'm going to go another half a position. I never trust any jetting charts. Every bike is a little different.
Thanks for the quick reply. I’ll give it a shot!
What do you use in your ultrasonic cleaner?
I use water & about a litre (quart) of Zoom Motorcycle Cleaner. It does a good job with aluminum parts & getting dirt stains off, but not great with anything greasy. It works well for me because I generally degrease in my varsol tank first.
Great video, thanks!
Quality video. You know your shit!
any opinion on JD needles?
I never experiment with them because it’s tough to find good info on them and the JD kits are over-priced if you just want the parts. I don’t need a kit. I have all the individual parts, so I just make the exact change I need.
Will the 40 power Jet be ok on 23 y125?
I haven’t tried it on a 125. Easy to test though.
@@ChuckfromTrueTech I say generally, if you are spitting oil in the mid range, the power jet is the first thing to go smaller on. I would like to see a vid on how to remove it. I never spent so much time jetting a carb to run perfectly, before this gimmick (IMO).
What a great video!!
Forgot to mention air mixture screw was 1.5 turns out and the reason is that im fouling plugs,thank you
There are too many variables to be able to say what jetting you need. Each bikes is a little different. If the engine is in good shape you should be very close to stock. If you’re struggling it’s often helpful to go back to stock and make small changes from there. Jetting charts are often way off.
Would you still recommend the 40 power jet?
You need to test every application, but I've found it to be helpful on most YZs I've jetted.@@dakstaverman62
Ok great thank you
The air screw, and pilot jet handle the jetting from idle to about 1/8th throttle opening, and I would bet you are riding with more throttle than that. You were probably fouling plugs,---where the power jet kicks in.
2000 rm 250 has the power jet carb .
I am not far into the vid, and I am sure you are going to clean everything. But taking apart a dirty assembly just bugs me. :)
Why clean it before disassembly and then clean it again?
@@ChuckfromTrueTech You never met my last girlfriend. Super clean freak. It was nice to see.
It's your video for the world to see. (a good vid) :)
I can smell the video
🤣
was never taught to say “zed” while learning the alphabet.
Most likely because Zee rhymes with G, P, V, (the last letters in each line) in the alphabet song. Zed comes from its Greek predecessor “Zeta.”
Soo lean I wouldn’t even touch a sand pit
Zeee dude, not ZED!!🤦 Wth?
YZ - (WHY-ZEE)
According to whom?
Chinese carbs are best for power.
🤣
the generic piece of paper he shows you starts at about 10:27 and is about a minute long and not game changing. Who wants to watch another carb cleaning video?
That "generic piece of paper" is from the owners manual. But I see a mistake on that too, (says the P-Jet shuts off at 8,500 rpm, and clearly shut off at 1/2 throttle. My 2019 manual says the same thing, but the P-Jet does not even open until 1/2 throttle. I am not a fan of the power jet.