Not to be negative here but as a long time engine builder and one who has built many high performance engines I can tell you that your thoughts on the stock slant head allowing more ful air mix in for combustion is off the charts dead wrong, the combustion chamber of the head has nothing to do with how much fuel is allowed in for combustion, the reason the Puch head has a potential to give you more power and torque on the same engine is because is causes the fuel air mix to be compressed tighter which creates high chamber pressure when combustion accurs which will put more down force on piston and thus create more power from the same amount of fuel, this is very basic knowledge of any and all experienced engine builders.
Yea like you said it only after thinking it over....flywheel is maybe to lite or is it right on ? Not into high rpms I'd like a heavier one I think.? I run a 56t rear sprocket with my hills and half throttle on the strait's is fun
TH-cam is a great tool for passing on useful information, it's also a great place to make a fool of yourself. This reminds me of an old saying" it's one thing for people to think your foolish and another to open your mouth and to remove all doubt". Your video sure did generate alot of good info in the comments, and I thank you for that.
I'm an engine guy. If you can keep her cool, more compression translates to more power and even efficiency all day. I do wish these bikes had flat top pistons for quench/squish purposes.
tridtionally the early models used flat top pistons but they are hard to find these days or you could special order one, which would allow full control
ThunderHead289 i bought 5 pistons took .24 of the tops of the pistons 2 months ago runing a 0.5 copper head gasket stock bottom. Puch head ngk bp5hs .29 gap getting damn close to stock temps
+DerKrawallkeks Well, if you want to make power with a two cycle engine, you should really only focus on having large (wide) transfers and a lot of exhaust port area. A two stroke needs to get a lot of rpm to make torque, and having ridiculously high compression ratio stops the engine from revving. The trick is in the squish band, being able to reach a lot of compression pressure with a possibly "bad" compression ratio. High compression also wears your engine down a lot quicker, and you will have to get new crank bearings/crankshafts/pin bearings much more often. In well engineered engines, the compression ratio is for the most part just fine, and doesn't require a raise. I hope I have been clear, post more questions if you want me to explain more specific things. I work with tuning two stroke engines, but my fist language is not English.
Thanks;) i know quite a bit about two strokes and engines, but not too much about compression. Sure, port area and resonance etc is very important, and compression causes wear, but still... on both 2stroke and 4 stroke, I thought compression will increase performance (if you take care of extra stress, engine knock etc).. Why not?
If i was fitting the Pooch head, then after silly puttying the piston and turning the engine over by hand found i needed to Relive the head some .. Just because i do not have a fancy machine shop .. i would temporally glue some emery paper to the top of the piston and with the jug bolted to the head use the piston to make the relief (kind of like lapping valves in a 4stroke ). so the shape is a perfect match between the 2 .. then of course make sure everything is cleaned up proper .. before re assembling.
I really appreciate you getting this topic on the "table". With the help of some knowledgeable posters the end result is very informative! Keep trying....
Matthew Schurter Ive gone to riding a Suzuki VLR1800 (C109RT) but still plan to get back to the motored bikes in the future....when I get really old and broke...LOL
What you told there is absolutely wrong, you are missing basic understanding of how an engine works. The for example 50cc of an engine is the volume which the piston displaces. This is what is responsible for how much new air/fuel mix is taken in. The size of the combustion chamber doesn't have anything to do with that. The result of a head with a smaller combustion chamber will increase compression a lot, therefore leading to much more power and possible engine knocking. Since those engines have low compression, I guess (only guess) that there is no danger of knocking/preignition. Only issue might be the highly increased power output and therefore wear/stress.
The EGR on my truck quit working and the engine started pinging. I said the same the "it's a low compression engine it won't hurt if I let it go for a while" (it's the 2.5L inline4 ford engine) the result was the rings and ring lands on piston 3 and 4 being broken.
DerKrawallkeks your 100% right there's only one way I've found around that problem and it's to use a higher octane fuel but it still pings up top sometimes and I'm still stuck on what oil ratio to use it doesn't like 20:1 but I've done it to a test engine so I'm just experimenting since doing it I've noticed in the last 2 weeks it's blowing smoke could be rings but it's only 2 months old this has only happened since i used a billet high comp head. i do have a spare engine fully ported with race piston and has a factory high compression head can't wait to see how that one runs it's not one of the cheap engines it's a super hawk racing 80cc they didn't make many of these from what i was told. But next will be a full house arrow racing engine there not cheap tho.
Interesting! Yes,I have the same: Now that I have done a compression mod (sanded down the cylinder+head and removed the gasket, I have btter compression. Still it should absolutely not knock, because it's now maybe 9:1 instead of 6:1. But it only pings at high rpm and full throttle(of course). Not sure why.. Maybe we have glowing carbon deposits in there or something.. the scavenging is really bad on those engines.
DerKrawallkeks with my head it's a copy of the rock solid brand head it can't be sanded down it's flush with the cylinder there's no lip or edge to sand down i wouldn't want to raise the comp by sanding down the cylinder head lol it's got to much comp as it is but it does ride nice as long as you don't take it over 60-70 kph I'm not sure what that is in miles I'm in Australia. I've just got to figure out the right oil mix I'm sure it's got something to do with it as well.
Why would you want to bring your compression ratio DOWN? The are already running what I would consider extremely low (6:1) in the first place. Every 2 stroke I have ever built, (and I have built several dirt bikes, and one quad) I have RAISED the compression ratio for increased performance. The most recent build was the quad, and it started stock with 36 hp. I wanted it to keep up with my CR 250, so it was in need of some help, and it was compression to the rescue! The stock head was only running either 8 or 9:1, but my performance head built by CPI Racing (a Polaris snowmobile racing specialist) was a custom built 13.25:1 "cool head" for my Scrambler. Between that, and their fatty pipe (extremely large expansion chamber), I picked up 15.5 hp on the dyno on a 400 cc single cylinder engine.Then added some Kevlar reeds, ported/polished the jug, ran a Wiseco piston with some huge windows, added a titanium crank & rod, then a power valve, and it was good for over 75 hp by the time it was done. I did have to run premium pump gas to avoid detonation, but it wasn't anything crazy like needing race gas. (although it did run awesome on some VP 104) I don't understand why you would recommend lower compression, unless you enjoy just putt putting around at 15 MPH. I've worked on a couple of friends motorized bikes, but never had one myself, so I'm currently planning a build on a 30 speed Motobecane Fantom 29 Elite, front suspension, hard tail mountain bike with hydraulic disc brakes. I want to be able to use the gears for the engine, so I'm planning on a jackshaft shift kit, and I'm shooting for 50+ MPH on pump gas, with one of these little CG engines, and I assure you my compression is going to be at least double of that weak a$$ 6:1! I understand not everyone has quite the need for speed that I have, but if it has 2 wheels, and won't pull wheelies, it's not worth having IMHO. The engine should be able to well out do what I can do with my legs.
The new head will increase compression, not cause more fuel air mixture to be drawn in. The increased compression and possibility of detonation can be taken care of with premium gas. That equals more power.
I would think that compression ratios would play a more significant role than the small difference in cylinder volume. Say total volume is 80cc with the slant head and 77.5 the Puch. Both will have the same bore and stroke, giving 66cc displacement to both. (80/(80-66)) for the slant head (77.5/(77.5-66)) for the Puch head So the slant head will have a 5.7:1 compression ratio, while the 6.7:1 compression ratio. Admittedly, my math is rough, and wrong, because I don't know anything about the porting or the carb and exhaust system, or the shape of the piston, but the principle is the same. I expect someone who professionally tunes these engines can provide FAR better figures. The higher compression ratio will allow you to get more energy out of the fuel you put in, but in a hot two stroke, operating at peak output, the higher compression engine setup will suffer from pre-ignition, also known as knocking. This can destroy engine components or cause the engine to diesel and "runaway." Long story short: Either head should be fine, as long as long as everything else is properly tuned, and you don't try to overwork the engine. The Puch head might squeeze a wee bit more out of the engine.
These are piston regulated intake 2strokes so the piston stroke dictates the cc of charge that will enter the engine, so increasing compression will help these motorised bike engine 2 strokes.
Kingtoneable a longer connecting rod is not possible as it would interfere with the bottom of the cylinder. in order to "stroke" an engind you have to buy a long stroke crank. a stroker crank increases the volume of air and fuel pulled into the cylinder by allowing the piston to drop farther down in the cylinder.
Kingtoneable and the shape on the inside of the head is a squish band and the concaved part with the spark plug in it is the combustion space. the piston nearly contacts the squish band forcing all air/fuel into the smaller combustion space increasing compression
Also, and I mean zero offense when I say this, but I would suggest doing some reading on engine operation theory before you make a video like this. You definitely have some working knowledge, but the information you present is also inaccurate, incomplete, or wrong and it can misinform people who are looking to you for good accurate information.
Where can I find one of these Puch heads that will work on my 66cc Wildcat 2-stroke "China Doll" engine? I did some searching for "Puch Head's" but there are so many options I didn't know which one would work for my engine?
Word of advice. For accurately measuring the CC volume of a combustion chamber you need to use a flat piece of glass or plexiglass with a hole in it for adding liquid. This will give you the flat chamber volume (the actual measure) and avoid errors caused by the "bubble" effect created from the water tension. Your "about 7.5cc" measure could have been off by a couple of tenths or more as a result.
even with the Plexiglas or the "Flat method" if you will, of measuring volume you aren't taking into consideration the dome affect of the piston. Oh well off to work now as millions on welfare are depending on me!
jumpa01 The dish of a piston would be measured in the same manner, The dome volume would be done with an impression, and again the same method (or the specs of the volume above crown if provided by manufacturer)
You neglect a mod from consideration, enlarging the combustion chamber. You could pretty easily cut another cc out in that transition between dome and squish band, and get close to the slant head volume with the mass advantage of the puch design toward cooling. That would negate adding gaskets, or shimming the cylinder, so effect the squish efficiency less, and have zero timing effect. BTW, it's pronounced to rhyme with "look", not like a French guy saying "push", lol. Add a cc of volume, run pump premium instead of regular, you should have little danger of detonation without playing with plug heat range unless you Hill climb in saharan summer type conditions. Excellent presentation and theory work though, and a great cautionary note for those looking for "bolt on and ride" parts who might not be inclined toward surgical solutions, lol
the squish band reduces detonation, the second way you reduce detonation is use high quality gas (91) octane. and no the slant head does have anything to do with holding more it hold thee same amount under more pressure. you can easily drop a puch head on a stock engine with the same gaskets.
Another thing is that you are wrong again about the Puch head shooting compression up to 190-200psi I have run compression test on my engines and they are in the 145-155psi and this is actually an idea compression range with only using one 0.020" gasket, you will not find any 2 stroke engine that normally runs a compression ratio above 175psi they simple just wont hold together for long above that according to the experts, A Puch head will not raise compression to an unsafe level, one note here also is that if you run the Puch 50cc head, two head gaskets must be used or piston will hit head because the chamber is smaller at it widest point compared to the 70cc Puch head, I run each on two different bikes and they perform great, compression is not to high with the Puch heads, I know this because I run them and know many other who also use them.
So the intake (downward) stroke will still pull the same amount of fuel. You are losing combustion chamber volume but it will still pull in the same amount...get me so far? As the piston goes top dead center its gonna SQUEEZE that intake charge more hence "higher compression". To alleviate detonation/ping...what has always been done it to reduce ignition timing. Polishing the combustion chamber like chrome helps a little also by reducing hot spots in that squish area. Furthermore that Puch/pool head obviously has more cooling just by the amount,size of fins and also its air flow down caricature of said fins. A great way to sell your parts is to try and show fault with others products. PUCH has been around the 2 stroke business since probably late 60 but definitely the 70's. Not to be a grump but stick with what you really know. Thank you for turning me onto that PUCH head. With a lil love on that squish band (just polishing) it's a great alternative to alot of high priced cnc poopoo
Just so you know and I hope you learn this by now liquid always levels itself out so I don't know what you're using that little tool to level the liquid out for
@ 7:45 u went wrong...20% ok....but it's the 75 to 100 cc in the cyl that is compressed into that combustion chamber.....higher it is more work it is to do put the power stroke also blows down hard...if only a flywheel of sorts to carry thru...
I’ve done it with water, simple and easy, even cc’d a head gasket by sealing it against a flat mirror with grease. U just have to keep the meniscus of the water in mind
@@ghettobikelife8833 ive also seen this method used in multicylinder 4stroke engines to balance the volume of each combustion chamber after rebuilding .. typically with a light weight oil .. .. the head needs to be secure and perfectly level for it to work correctly .. .( and can use glass or Plexiglas .. as you mentioned to stop the fluid bulge ,at the top when the liquid becomes convex ..
The larger combustion chamber on the slant head does NOT translate into more power, all things taken into consideration. Actually, the lower volume Puch head will give the engine a higher compression ratio, thus giving the engine more power potential. Contrary to what the video poster says about the larger combustion chamber meaning more fuel is inside the chamber- The fuel volume is controlled by the carb, not the combustion chamber volume. Increasing the combustion chamber volume has no effect on how much fuel the carb feeds to the engine.
if you get pinking, or pinging as its called in usa, just run higher octane fuel. it helps with heat issues too slightly. i have a sym 50cc scooter that pinks and runs hot (standard no mods), when run on unleaded 95 ron, but on super plus 99 ron it runs perfect, its recommended octane rating in the manual is 90 ron, i hate to think what it would run like on that. 95 ron fuel is the lowest we have in uk, 99 the highest, aviation petrol is 101 ron but its like finding hens teeth. in the usa i understand you have more choice, play around try different octane fuel, it may help, and with what these engines do to a gallon spending a few pennies a litre more is negligible.
Preignition and detonation is an engines worst nightmare. If a car engine is under load, as going uphill, and "pings" just drop to the next lower gear. But these little 2 strokes do not make much hp so preignition can be from "hotspots" or the timing is too far advanced. The piston can and will be damaged by improper timing.
Selling the slant head? Tests show it works worse than the stock because the spark plug needs to be in the center. I shaved my stock head down to the main fin and the compression is not too high. I do have all high quality bearings all around and am using a Yamaha conrod and have changed the crank balance using the new calculation method. Also the Jaguar CDI is neccesary in general and I have the jumpers set for maximum retardation at higher rpms while leaving the lower range advanced. No detonation problems anymore. But the rap about the more space in the head giving it more air fuel mix toburn just blew me away. Please send me some of that dope you've got there! ;-)!!! I recommend tuners to order and apply some Techline racing coatings. Thermal barrier on the piston crown and inside of the head and DFL super slick coat for the piston skirts and or bearing journals/pins. There's another company , Swaney or something like that. They do it too. There are some companies that you can just send the parts to and they will do it for you. Like $40 for a piston or so. I did mine myself.
20% more fuel with the same jetting. A givin carb jet is gonna deliver the same amount of fuel on the same engine even with a different head. A larger combustion chamber isn't going to let it suck 20% more fuel in, the slant head just won't squeeze it as hard bro. Low comprehension engines like 80's/90's 5.0's are 9.1:1 & will take a ton of ignition timing compared to a high compression 289 hips but the 289 made 271hp & the 5.0 made 225hp. Apples to Oranges?
its pronounced "PUCK", great vids man, the dome on the piston crown affects the squish volume, how you demonstrated it would only be relevant for flat top pistons, but squish volume does not affect displacement only compression. also the syringe technique is only any use for balancing the compression on multi cylinder heads.
I haven't heard anyone pronounce it as "Puck".. It's supposed to be pronounced "Pook" AFAIK, at least according to every video I've ever seen and everyone I've talked to
What you are saying is somewhat correct. But also not. It's true that having less volume of cylinder head space will reduce the amount of air and fuel that can be drawn into the chamber. BUT the opposing result of having the combined volume of total that can be drawn into the Chamber and then compressed into a smaller area is whats important here. By using the smaller volume head you are increasing your compression ratio. And there for power output should climb almost always. As long as you are using the correct ignition timing and fuel for it. Usually with higher compression you will need to retard the ignition to prevent pre detonation. So basically I am saying you are correct. Except you are worrying about a minute detail that in the bigger picture matters little.
You measured the puch head wrong. You filled up the squish band with fluid too. If you have the piston/squishband where they should be you only measure the bowl where the plug is.
Hey dude love your vids, I own a generic trigger sm5sm and I'm looking for the best way to increase the top speed of the bike, it takes of really nicely and has good acceleration but want more top end? I've thought about putting a 77cc big bore kit but do you (or anybody Else) have any other ideas? Keep up the vids Bro, thanks
Just change the exhust, it will work much better with just that. Keep in mind that the Generic Trigger uses a copy of an am6 engine and not an actual am6 engine so the quality is not as good, therefore if you want to put on a bigbore kit you should probably change the crank. and don't forget that a bigbore kit need a bigger carb to breathe well. In other words, just buying a performance exhaust is simpler and less expensive/complicated.
Please dont think I'm hating on you here because Im not at all, but honestly people looking to know the truth about something need to actually be told the truth and not just given theory that isnt based in fact, I like you guys at Juice motors and have ordered several parts and gaskets from you guys, ya'll have some great products but this video about the Puch head vs the slant just isnt correct in some areas and I wanted to speak up so that others can have an experienced opinion from someone who has been using the heads for a long time and has 45+mph bikes because of my parts matching and port work. Thanks for all the great parts and I hope what I have posted in the section doesn't rub anyone wrong.. Peace Map
WRONG! Stacking head gaskets to reduce static compression ratios is just lamb and wrong!!! It will kill the flame front and the torque. It is a giant waste of fuel and will cause after-burn in the exhaust system. Johan Engqvist said it best.
hi, how are you? First of all I want to congratulate you for your great work on the channel, second I have a webpage and youtube channel called bicimotos argentina, of course in spanish, and I want to know if you let us translate your videos to spanish to share all the information with our people cause only a few can understand English, and your vids are amazing and explains a lot of thing. I wait your answer, thank you. Carlos
100% wrong ,same fuel goes in its just more compression,has nothing to do with size of head in cc,its total volum area for bore that dictates amount of fuel,smaller head allows more compression hence more power and that head will cool better
I have bin Building Skyhawk engines for over 6 years now/P also have pics.If you really want a good head get a real Fred Head.He makes all kinds even 1. 2 or 3 spark plugs.His Name is Fred Chelminsik.The real Fred Head maker .Check him out.He is a Master.Happy Riding.
lol as an Austrian (btw Puch is from Austria and not Germany), I know how to pronounce it the right way. Lets just say I cringe every time u say it. lol.
these junk china motors are total crap i cant believe you people try to modify them! there not to be driven more than 15 minutes or even idol more than 30 seconds! there not made right to be on bikes someone needs to just make new motors from ground up!
Nah their great super cheap hobby to mess with and when u break it or mess up the ports by taking to much aluminum away u can afford to replace it n start over. I’m not sayin they r well made or anything just sayin they r just the right price for a fun cheap hobby to enjoy the hell outta.
Not to be negative here but as a long time engine builder and one who has built many high performance engines I can tell you that your thoughts on the stock slant head allowing more ful air mix in for combustion is off the charts dead wrong, the combustion chamber of the head has nothing to do with how much fuel is allowed in for combustion, the reason the Puch head has a potential to give you more power and torque on the same engine is because is causes the fuel air mix to be compressed tighter which creates high chamber pressure when combustion accurs which will put more down force on piston and thus create more power from the same amount of fuel, this is very basic knowledge of any and all experienced engine builders.
Yea like you said it only after thinking it over....flywheel is maybe to lite or is it right on ? Not into high rpms I'd like a heavier one I think.? I run a 56t rear sprocket with my hills and half throttle on the strait's is fun
mapbike Dead nuts on. Higher compression with the Puch. .
He had me cornfused.
Increase compression. Then five head gaskets to bring CR down ?
Thank you for saying it first, so I wouldn't have to.
Exactly right bud.., compression makes power ....
TH-cam is a great tool for passing on useful information, it's also a great place to make a fool of yourself. This reminds me of an old saying" it's one thing for people to think your foolish and another to open your mouth and to remove all doubt".
Your video sure did generate alot of good info in the comments, and I thank you for that.
I'm an engine guy. If you can keep her cool, more compression translates to more power and even efficiency all day. I do wish these bikes had flat top pistons for quench/squish purposes.
tridtionally the early models used flat top pistons but they are hard to find these days or you could special order one, which would allow full control
ThunderHead289 i bought 5 pistons took .24 of the tops of the pistons 2 months ago runing a 0.5 copper head gasket stock bottom. Puch head ngk bp5hs .29 gap getting damn close to stock temps
how did the puch head not give you more power? shouldn't all that extra compression increase power?
yes it does
High compression in a two stroke is really bad for performance.
+Johan Engqvist Why is it bad on a two stroke?
+DerKrawallkeks Well, if you want to make power with a two cycle engine, you should really only focus on having large (wide) transfers and a lot of exhaust port area. A two stroke needs to get a lot of rpm to make torque, and having ridiculously high compression ratio stops the engine from revving. The trick is in the squish band, being able to reach a lot of compression pressure with a possibly "bad" compression ratio. High compression also wears your engine down a lot quicker, and you will have to get new crank bearings/crankshafts/pin bearings much more often. In well engineered engines, the compression ratio is for the most part just fine, and doesn't require a raise. I hope I have been clear, post more questions if you want me to explain more specific things. I work with tuning two stroke engines, but my fist language is not English.
Thanks;) i know quite a bit about two strokes and engines, but not too much about compression.
Sure, port area and resonance etc is very important, and compression causes wear, but still... on both 2stroke and 4 stroke, I thought compression will increase performance (if you take care of extra stress, engine knock etc).. Why not?
If i was fitting the Pooch head, then after silly puttying the piston and turning the engine over by hand found i needed to Relive the head some .. Just because i do not have a fancy machine shop .. i would temporally glue some emery paper to the top of the piston and with the jug bolted to the head use the piston to make the relief (kind of like lapping valves in a 4stroke ). so the shape is a perfect match between the 2 .. then of course make sure everything is cleaned up proper .. before re assembling.
I really appreciate you getting this topic on the "table". With the help of some knowledgeable posters the end result is very informative! Keep trying....
JOHN DEERE what you said :) !
Matthew Schurter Ive gone to riding a Suzuki VLR1800 (C109RT) but still plan to get back to the motored bikes in the future....when I get really old and broke...LOL
What you told there is absolutely wrong, you are missing basic understanding of how an engine works.
The for example 50cc of an engine is the volume which the piston displaces. This is what is responsible for how much new air/fuel mix is taken in. The size of the combustion chamber doesn't have anything to do with that. The result of a head with a smaller combustion chamber will increase compression a lot, therefore leading to much more power and possible engine knocking. Since those engines have low compression, I guess (only guess) that there is no danger of knocking/preignition. Only issue might be the highly increased power output and therefore wear/stress.
The EGR on my truck quit working and the engine started pinging. I said the same the "it's a low compression engine it won't hurt if I let it go for a while" (it's the 2.5L inline4 ford engine) the result was the rings and ring lands on piston 3 and 4 being broken.
DerKrawallkeks your 100% right there's only one way I've found around that problem and it's to use a higher octane fuel but it still pings up top sometimes and I'm still stuck on what oil ratio to use it doesn't like 20:1 but I've done it to a test engine so I'm just experimenting since doing it I've noticed in the last 2 weeks it's blowing smoke could be rings but it's only 2 months old this has only happened since i used a billet high comp head. i do have a spare engine fully ported with race piston and has a factory high compression head can't wait to see how that one runs it's not one of the cheap engines it's a super hawk racing 80cc they didn't make many of these from what i was told. But next will be a full house arrow racing engine there not cheap tho.
Interesting! Yes,I have the same: Now that I have done a compression mod (sanded down the cylinder+head and removed the gasket, I have btter compression. Still it should absolutely not knock, because it's now maybe 9:1 instead of 6:1.
But it only pings at high rpm and full throttle(of course). Not sure why..
Maybe we have glowing carbon deposits in there or something.. the scavenging is really bad on those engines.
DerKrawallkeks with my head it's a copy of the rock solid brand head it can't be sanded down it's flush with the cylinder there's no lip or edge to sand down i wouldn't want to raise the comp by sanding down the cylinder head lol it's got to much comp as it is but it does ride nice as long as you don't take it over 60-70 kph I'm not sure what that is in miles I'm in Australia. I've just got to figure out the right oil mix I'm sure it's got something to do with it as well.
DerKrawallkeks while I'm here check these engines out i so badly want the 9.5 hp one arrowmotorizedcycles.com/index.html
Why would you want to bring your compression ratio DOWN? The are already running what I would consider extremely low (6:1) in the first place. Every 2 stroke I have ever built, (and I have built several dirt bikes, and one quad) I have RAISED the compression ratio for increased performance. The most recent build was the quad, and it started stock with 36 hp. I wanted it to keep up with my CR 250, so it was in need of some help, and it was compression to the rescue! The stock head was only running either 8 or 9:1, but my performance head built by CPI Racing (a Polaris snowmobile racing specialist) was a custom built 13.25:1 "cool head" for my Scrambler. Between that, and their fatty pipe (extremely large expansion chamber), I picked up 15.5 hp on the dyno on a 400 cc single cylinder engine.Then added some Kevlar reeds, ported/polished the jug, ran a Wiseco piston with some huge windows, added a titanium crank & rod, then a power valve, and it was good for over 75 hp by the time it was done. I did have to run premium pump gas to avoid detonation, but it wasn't anything crazy like needing race gas. (although it did run awesome on some VP 104) I don't understand why you would recommend lower compression, unless you enjoy just putt putting around at 15 MPH. I've worked on a couple of friends motorized bikes, but never had one myself, so I'm currently planning a build on a 30 speed Motobecane Fantom 29 Elite, front suspension, hard tail mountain bike with hydraulic disc brakes. I want to be able to use the gears for the engine, so I'm planning on a jackshaft shift kit, and I'm shooting for 50+ MPH on pump gas, with one of these little CG engines, and I assure you my compression is going to be at least double of that weak a$$ 6:1! I understand not everyone has quite the need for speed that I have, but if it has 2 wheels, and won't pull wheelies, it's not worth having IMHO. The engine should be able to well out do what I can do with my legs.
Sorry about my typos. You get the gist though right?
The new head will increase compression, not cause more fuel air mixture to be drawn in. The increased compression and possibility of detonation can be taken care of with premium gas. That equals more power.
Do ya have to resize or redrill a puch head?
i can see why there isn't any update videos for so long and this video clearly explain why.
This guy has no idea what he’s talking about
Can a gy6 47mm piston run in this engine
were to get the head and cylinder
Instead of stacking head gaskets, wouldn't it be better to use a higher octane fuel and advance the spark timing?
He clearly has very basic knowledge of how engines work
I would think that compression ratios would play a more significant role than the small difference in cylinder volume. Say total volume is 80cc with the slant head and 77.5 the Puch. Both will have the same bore and stroke, giving 66cc displacement to both.
(80/(80-66)) for the slant head
(77.5/(77.5-66)) for the Puch head
So the slant head will have a 5.7:1 compression ratio, while the 6.7:1 compression ratio. Admittedly, my math is rough, and wrong, because I don't know anything about the porting or the carb and exhaust system, or the shape of the piston, but the principle is the same. I expect someone who professionally tunes these engines can provide FAR better figures.
The higher compression ratio will allow you to get more energy out of the fuel you put in, but in a hot two stroke, operating at peak output, the higher compression engine setup will suffer from pre-ignition, also known as knocking. This can destroy engine components or cause the engine to diesel and "runaway."
Long story short: Either head should be fine, as long as long as everything else is properly tuned, and you don't try to overwork the engine. The Puch head might squeeze a wee bit more out of the engine.
i have a suzuki motorcycle and it only runs 118kph
how can i tune it up
Hey man do u think the "stage 1 performance cdl" that bike berry sells is worth it or no?
you over filled the second one totally visible. correct me if im not seeing that right
These are piston regulated intake 2strokes so the piston stroke dictates the cc of charge that will enter the engine, so increasing compression will help these motorised bike engine 2 strokes.
Higher the compression the better the performance and the higher octane fuel you need to prevent detonation.
And stop saying the head can hold more fuel. That's a dumb thing to say. It doesn't actually fill the cylinder with fuel its an air/fuel charge
your right
Kingtoneable that is completely incorrect
Kingtoneable a longer connecting rod is not possible as it would interfere with the bottom of the cylinder. in order to "stroke" an engind you have to buy a long stroke crank. a stroker crank increases the volume of air and fuel pulled into the cylinder by allowing the piston to drop farther down in the cylinder.
Kingtoneable and the shape on the inside of the head is a squish band and the concaved part with the spark plug in it is the combustion space. the piston nearly contacts the squish band forcing all air/fuel into the smaller combustion space increasing compression
Also, and I mean zero offense when I say this, but I would suggest doing some reading on engine operation theory before you make a video like this. You definitely have some working knowledge, but the information you present is also inaccurate, incomplete, or wrong and it can misinform people who are looking to you for good accurate information.
Can you give me a link to where I can buy this
Where can I find one of these Puch heads that will work on my 66cc Wildcat 2-stroke "China Doll" engine? I did some searching for "Puch Head's" but there are so many options I didn't know which one would work for my engine?
All puch heads and cylinders habe the same stroke and boltpattern. By that i mean all 50-70cc
@@nikolaierikssonkukkonen9878 all puch heads have same bolt spacing that’s just the ones that look like this or literally all 50-70cc
the heads aren't made by Puch they are made for puch. it's pronounced pook.
you could use a dished piston from morini to decrease the ratio of the CR
is anyone running alcohol or nitro on these engines yet? I'm thinking the reed pressure might be too high? but would be interesting in find out.
Word of advice. For accurately measuring the CC volume of a combustion chamber you need to use a flat piece of glass or plexiglass with a hole in it for adding liquid. This will give you the flat chamber volume (the actual measure) and avoid errors caused by the "bubble" effect created from the water tension. Your "about 7.5cc" measure could have been off by a couple of tenths or more as a result.
even with the Plexiglas or the "Flat method" if you will, of measuring volume you aren't taking into consideration the dome affect of the piston. Oh well off to work now as millions on welfare are depending on me!
jumpa01 The dish of a piston would be measured in the same manner, The dome volume would be done with an impression, and again the same method (or the specs of the volume above crown if provided by manufacturer)
when I cc heads I get a cheap picture frame and remove the glass and I use power steering fluid as the liquid.
You neglect a mod from consideration, enlarging the combustion chamber. You could pretty easily cut another cc out in that transition between dome and squish band, and get close to the slant head volume with the mass advantage of the puch design toward cooling. That would negate adding gaskets, or shimming the cylinder, so effect the squish efficiency less, and have zero timing effect. BTW, it's pronounced to rhyme with "look", not like a French guy saying "push", lol. Add a cc of volume, run pump premium instead of regular, you should have little danger of detonation without playing with plug heat range unless you Hill climb in saharan summer type conditions. Excellent presentation and theory work though, and a great cautionary note for those looking for "bolt on and ride" parts who might not be inclined toward surgical solutions, lol
whats the music?
Thomas Schwartz & Fausto Fanizza - Twilight On Mars
help my motor 80 cc leaking tru THE carburetor how to fix it and my bike nOt the starting wat to do
+clarence blackwood Sounds like the head gasket is gone.. let me know how you get on
The head gasket on a pouch motor is 5 times thicker than on a motorized bike, ouch did that to lower the compression
the squish band reduces detonation, the second way you reduce detonation is use high quality gas (91) octane. and no the slant head does have anything to do with holding more it hold thee same amount under more pressure. you can easily drop a puch head on a stock engine with the same gaskets.
Another thing is that you are wrong again about the Puch head shooting compression up to 190-200psi I have run compression test on my engines and they are in the 145-155psi and this is actually an idea compression range with only using one 0.020" gasket, you will not find any 2 stroke engine that normally runs a compression ratio above 175psi they simple just wont hold together for long above that according to the experts, A Puch head will not raise compression to an unsafe level, one note here also is that if you run the Puch 50cc head, two head gaskets must be used or piston will hit head because the chamber is smaller at it widest point compared to the 70cc Puch head, I run each on two different bikes and they perform great, compression is not to high with the Puch heads, I know this because I run them and know many other who also use them.
So the intake (downward) stroke will still pull the same amount of fuel. You are losing combustion chamber volume but it will still pull in the same amount...get me so far? As the piston goes top dead center its gonna SQUEEZE that intake charge more hence "higher compression".
To alleviate detonation/ping...what has always been done it to reduce ignition timing. Polishing the combustion chamber like chrome helps a little also by reducing hot spots in that squish area. Furthermore that Puch/pool head obviously has more cooling just by the amount,size of fins and also its air flow down caricature of said fins.
A great way to sell your parts is to try and show fault with others products. PUCH has been around the 2 stroke business since probably late 60 but definitely the 70's. Not to be a grump but stick with what you really know.
Thank you for turning me onto that PUCH head. With a lil love on that squish band (just polishing) it's a great alternative to alot of high priced cnc poopoo
Just so you know and I hope you learn this by now liquid always levels itself out so I don't know what you're using that little tool to level the liquid out for
@ 7:45 u went wrong...20% ok....but it's the 75 to 100 cc in the cyl that is compressed into that combustion chamber.....higher it is more work it is to do put the power stroke also blows down hard...if only a flywheel of sorts to carry thru...
song name @0:30
Thomas Schwartz & Fausto Fanizza - Twilight On Mars
More compression equals more power more generally across the range. And adjust your timing and increase your fuel octane.
puch is AUSTRIAN
no one cares
@@Shyzah gangsta alert
no one checks the cc of the head that way
Exactly what I thought. You're supposed to cast an aluminum/paper/wax model of the combustion chamber and put the model in a measuring glass.
Johan Engqvist wax, maybe. I can’t imagine anyone on earth making an aluminum casting just to find the cc’s (and how do u make a paper casting lol)
I’ve done it with water, simple and easy, even cc’d a head gasket by sealing it against a flat mirror with grease. U just have to keep the meniscus of the water in mind
@@ghettobikelife8833 ive also seen this method used in multicylinder 4stroke engines to balance the volume of each combustion chamber after rebuilding .. typically with a light weight oil .. .. the head needs to be secure and perfectly level for it to work correctly .. .( and can use glass or Plexiglas .. as you mentioned to stop the fluid bulge ,at the top when the liquid becomes convex ..
The larger combustion chamber on the slant head does NOT translate into more power, all things taken into consideration. Actually, the lower volume Puch head will give the engine a higher compression ratio, thus giving the engine more power potential. Contrary to what the video poster says about the larger combustion chamber meaning more fuel is inside the chamber- The fuel volume is controlled by the carb, not the combustion chamber volume. Increasing the combustion chamber volume has no effect on how much fuel the carb feeds to the engine.
+John B exactly...finally a smart person on here.
And run cooler...
if you get pinking, or pinging as its called in usa, just run higher octane fuel. it helps with heat issues too slightly.
i have a sym 50cc scooter that pinks and runs hot (standard no mods), when run on unleaded 95 ron, but on super plus 99 ron it runs perfect, its recommended octane rating in the manual is 90 ron, i hate to think what it would run like on that.
95 ron fuel is the lowest we have in uk, 99 the highest, aviation petrol is 101 ron but its like finding hens teeth.
in the usa i understand you have more choice, play around try different octane fuel, it may help, and with what these engines do to a gallon spending a few pennies a litre more is negligible.
why are you flicking the syringe? ? don't even try taking the bubbles out, just meaninglessly flick it.................................why?
Preignition and detonation is an engines worst nightmare. If a car engine is under load, as going uphill, and "pings" just drop to the next lower gear. But these little 2 strokes do not make much hp so preignition can be from "hotspots" or the timing is too far advanced. The piston can and will be damaged by improper timing.
was that starbuzz good btw I see that container lol
Selling the slant head? Tests show it works worse than the stock because the spark plug needs to be in the center. I shaved my stock head down to the main fin and the compression is not too high. I do have all high quality bearings all around and am using a Yamaha conrod and have changed the crank balance using the new calculation method. Also the Jaguar CDI is neccesary in general and I have the jumpers set for maximum retardation at higher rpms while leaving the lower range advanced. No detonation problems anymore. But the rap about the more space in the head giving it more air fuel mix toburn just blew me away. Please send me some of that dope you've got there! ;-)!!! I recommend tuners to order and apply some Techline racing coatings. Thermal barrier on the piston crown and inside of the head and DFL super slick coat for the piston skirts and or bearing journals/pins. There's another company , Swaney or something like that. They do it too. There are some companies that you can just send the parts to and they will do it for you. Like $40 for a piston or so. I did mine myself.
Did he really have to flick the air out of the syringe he's not injecting it into himself
Force of habit
Tune the carb to run leaner and use smaller jets in the carb and you’ll be fine with out changing timing or adding note gaskets
Smaller jets would make the problem with heat/detonation worse
its called a squishy because you put something in the cylinder and squish it then you measure your squishy measurement. i like silly-putty
I need a cylinder in a type B piston hook it up
20% more fuel with the same jetting. A givin carb jet is gonna deliver the same amount of fuel on the same engine even with a different head. A larger combustion chamber isn't going to let it suck 20% more fuel in, the slant head just won't squeeze it as hard bro.
Low comprehension engines like 80's/90's 5.0's are 9.1:1 & will take a ton of ignition timing compared to a high compression 289 hips but the 289 made 271hp & the 5.0 made 225hp. Apples to Oranges?
its pronounced "PUCK", great vids man, the dome on the piston crown affects the squish volume, how you demonstrated it would only be relevant for flat top pistons, but squish volume does not affect displacement only compression.
also the syringe technique is only any use for balancing the compression on multi cylinder heads.
I haven't heard anyone pronounce it as "Puck".. It's supposed to be pronounced "Pook" AFAIK, at least according to every video I've ever seen and everyone I've talked to
pook dude! not poosh nd they were made in graz austria, not germano!
What you are saying is somewhat correct. But also not. It's true that having less volume of cylinder head space will reduce the amount of air and fuel that can be drawn into the chamber. BUT the opposing result of having the combined volume of total that can be drawn into the Chamber and then compressed into a smaller area is whats important here. By using the smaller volume head you are increasing your compression ratio. And there for power output should climb almost always. As long as you are using the correct ignition timing and fuel for it. Usually with higher compression you will need to retard the ignition to prevent pre detonation.
So basically I am saying you are correct. Except you are worrying about a minute detail that in the bigger picture matters little.
You measured the puch head wrong. You filled up the squish band with fluid too. If you have the piston/squishband where they should be you only measure the bowl where the plug is.
Just mix your fuel with race gas to raise octane. and this head shines all day.
Hey dude love your vids, I own a generic trigger sm5sm and I'm looking for the best way to increase the top speed of the bike, it takes of really nicely and has good acceleration but want more top end? I've thought about putting a 77cc big bore kit but do you (or anybody Else) have any other ideas? Keep up the vids Bro, thanks
Meant sm50 not "sm5sm"
Meant sm50 not "sm5sm"
Just change the exhust, it will work much better with just that. Keep in mind that the Generic Trigger uses a copy of an am6 engine and not an actual am6 engine so the quality is not as good, therefore if you want to put on a bigbore kit you should probably change the crank. and don't forget that a bigbore kit need a bigger carb to breathe well. In other words, just buying a performance exhaust is simpler and less expensive/complicated.
I think it's called a squish band
puch is a 100 year old compeny
If the puch head was milled out a bit then i think it would be nice!
This puch head who bike is??? Original ....excuse my English so basic
Please dont think I'm hating on you here because Im not at all, but honestly people looking to know the truth about something need to actually be told the truth and not just given theory that isnt based in fact, I like you guys at Juice motors and have ordered several parts and gaskets from you guys, ya'll have some great products but this video about the Puch head vs the slant just isnt correct in some areas and I wanted to speak up so that others can have an experienced opinion from someone who has been using the heads for a long time and has 45+mph bikes because of my parts matching and port work. Thanks for all the great parts and I hope what I have posted in the section doesn't rub anyone wrong.. Peace Map
WRONG! Stacking head gaskets to reduce static compression ratios is just lamb and wrong!!! It will kill the flame front and the torque. It is a giant waste of fuel and will cause after-burn in the exhaust system. Johan Engqvist said it best.
Uh what the hell is Effigacy?¿ :● I think you meant " Efficiency "
Who cares if u messed up on the facts in this video, u should upload again
hi, how are you?
First of all I want to congratulate you for your great work on the channel, second I have a webpage and youtube channel called bicimotos argentina, of course in spanish, and I want to know if you let us translate your videos to spanish to share all the information with our people cause only a few can understand English, and your vids are amazing and explains a lot of thing.
I wait your answer, thank you.
Carlos
100% wrong ,same fuel goes in its just more compression,has nothing to do with size of head in cc,its total volum area for bore that dictates amount of fuel,smaller head allows more compression hence more power and that head will cool better
I have bin Building Skyhawk engines for over 6 years now/P also have pics.If you really want a good head get a real Fred Head.He makes all kinds even 1. 2 or 3 spark plugs.His Name is Fred Chelminsik.The real Fred Head maker .Check him out.He is a Master.Happy Riding.
Puch is Austrian
that is a puch Hi comp head FYI
it's not like the ch in church, it's ch like heckler and koch.
😂😂 no they're not drugs ha! Who in the comments thought "drugs😐" when they saw the 💉?
his drugs are to the left of him slightly off camera he failed to mention that
lol as an Austrian (btw Puch is from Austria and not Germany), I know how to pronounce it the right way. Lets just say I cringe every time u say it. lol.
Im building stihl ts400 cylinders on china dolls
this guy keeps stumbling over his words
Pronounced "POOK".
It's actually pronounced 'pook'...just sayin' is all...
Putch
E85? 110!!!
It's pronounced PUKE NOT POOSH PUCH
Most people in this "motorized bike" community lack basic understanding of how two stroke motors work, including you.
Exactly what I was thinking
pushh head ????? lol loooool say it right like i speel it " puk lol push head
It's pronounced pook.
Are you honestly "spreading" water as if it's butter or something? I can't even take you seriously now.
School yourself
Moped head
your wrong
these junk china motors are total crap i cant believe you people try to modify them! there not to be driven more than 15 minutes or even idol more than 30 seconds! there not made right to be on bikes someone needs to just make new motors from ground up!
Nah their great super cheap hobby to mess with and when u break it or mess up the ports by taking to much aluminum away u can afford to replace it n start over. I’m not sayin they r well made or anything just sayin they r just the right price for a fun cheap hobby to enjoy the hell outta.