49cc Pocketbike engine on bicycle?

Will'smotobikes19

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Hi guys I was just wondering if anyone knows if the huasheng 49cc 4 stroke gearboxes will bolt onto the 2 stroke pocket bike engines. I know they're a bit under powered but they're pretty cheap and you can get an upgraded version of them and they have a centrifugal clutch too. I've seen 2 or 3 bikes on YouTube they use a pretty small chain with the stock gearbox though.
 


Frankenstein

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Hi guys I was just wondering if anyone knows if the huasheng 49cc 4 stroke gearboxes will bolt onto the 2 stroke pocket bike engines. I know they're a bit under powered but they're pretty cheap and you can get an upgraded version of them and they have a centrifugal clutch too. I've seen 2 or 3 bikes on YouTube they use a pretty small chain with the stock gearbox though.
Maybe, the 49cc pocketbike motors tend to use a 75mm (3in) clutch, and a lot of them seem to use the same bolt on pattern.
 

Will'smotobikes19

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I have the parts from an old pocketbike engine I bought a few years ago for like $70 it didn't run much before i dropped it on the floor and cracked the crankcase. I need a new crankcase which is like $26 or the one half and a new magneto and then the gaskets since it should work I might get the huasheng transmission too. Budget build? lol I might get one of the aluminum gasbike gt frames since theyr'e lighter and it is a small engine. Maybe the 4 stroke mount would work to mount the engine?if it didn't line up I guess I could drill holes. I think I'm going to port and polish the exhaust port on the cylinder too. Then comes the exhaust, what would clear the mounting bracket and frame? either way my 79cc predator bike isn't working right anymore I think it has a slight bend in the shaft. When i try to start it it catches on something and stops running immediately, also the stupid set screw keeps coming loose on the jackshaft sprocket even with red loctite on it. I wonder if the speeds would be the same as the regular 48cc 2 strokes I've seen people on youtube use them on stand up scooters and a few bikes with them but they usually used the smaller size chain.
 

FurryOnTheInside

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What kind of pocket bike engine are you thinking of? I was looking and apparently there are quite a few different ones.
bd8c.jpg

I see a lot of the one that's top right corner of this picture, they are nice and flat so they'll fit in some of the weird frames that the 66cc won't, and they seem common enough that getting parts won't be too much trouble. I'm interested in trying one sometime. I have enough engines for most of this year though, lol! :oops:
I have seen some gearboxes that are listed as CVT gearboxes but I don't think they are CVT or multiple speeds, they don't even specify the reduction! I saw one with a sprocket that looks like it's for bicycle chain, I think it's the same product as used on the 4 stroke kits. I would love to know how to replace the stubby shaft that the sprocket is on with a longer shaft to have the chain on the right hand side.
 

Will'smotobikes19

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E108 is the engine I have, except for it has the clutch with the tiny 7 tooth sprocket meant for 25H chain and the stupid plastic pull start broke too so I ordered an aluminum one that I barely used. Some of those other engines look cool some look water cooled! the huasheng transmissions have a removable output sprocket right? maybe you could put a #35 sprocket on it and use #35 instead of #415 to help the engine with acceleration, then I could get a #35 sprocket and drill the holes in it for the cnc hub adapter. I'm wondering what the NGK plug equivalent is on the E108.
 

FurryOnTheInside

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E108 is the engine I have, except for it has the clutch with the tiny 7 tooth sprocket meant for 25H chain and the stupid plastic pull start broke too so I ordered an aluminum one that I barely used. Some of those other engines look cool some look water cooled! the huasheng transmissions have a removable output sprocket right? maybe you could put a #35 sprocket on it and use #35 instead of #415 to help the engine with acceleration, then I could get a #35 sprocket and drill the holes in it for the cnc hub adapter. I'm wondering what the NGK plug equivalent is on the E108.
Some are definitely water cooled, but the one in the pic "E107" is everywhere online which is more important for me as there'll be better parts availability and compatibility. Although it looks like they would all take the same clutch bell/transmission/reduction.
I wouldn't mind #35 chain if it has to have a separate jackshaft, as long as I could find a #35 sprocket to mount on the jackshaft. This shorter pitch chain would be a bit smoother, I reckon.
Since they are all pull start engines I really think they ought to freewheel at the hub, personally, and I would love to have the jackshaft included straight from the transmission.

Hoping I can get one before the end of the year so i can start figuring out what I can do with it. I have to build (and pay for) another whole shifter MB first though. :)
 

Will'smotobikes19

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For the huasheng gearboxes I heard the single chain is no good and you should go for the 2 chain version or better yet the belt drive transmission. The regular gearbox on e108 may or may not work even if you could change the output sprocket. Frankenstein said the huasheng gearbox should bolt up. I think there's even a racing clutch meant for the 49cc cags that has lighter springs? Idk I saw it on a website that sells parts for them.
 

FurryOnTheInside

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For the huasheng gearboxes I heard the single chain is no good and you should go for the 2 chain version or better yet the belt drive transmission. The regular gearbox on e108 may or may not work even if you could change the output sprocket
I need to see inside these things, which I never have.
There's not so much choice in my country, no HuaSheng branded products that I have found, and the descriptions of the products are so lacking in detail. They expect you to have bought a complete bike with a model number and they just list parts as fitting that bike. :(
I'll have to try to find some good pocket bike and mini bike forums to trawl up the info, and hopefully see whether it's possible to do what I have in mind.
 

Will'smotobikes19

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I guess you don't live in America then. Lots of things are sold that are made in china here, china isn't too bad at making electronics but engines not so much but they sell 44mm big bore kits for the 49cc pocketbike engines which is I think 60cc. The engine I have is already reed valve but its on the other side of the engine from the cylinder kinda weird.
 

Street Ryderz

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I guess you don't live in America then. Lots of things are sold that are made in china here, china isn't too bad at making electronics but engines not so much but they sell 44mm big bore kits for the 49cc pocketbike engines which is I think 60cc. The engine I have is already reed valve but its on the other side of the engine from the cylinder kinda weird.
The reeds being on the other side (case induction) is the best way to use a reed block set up,it also allows for a third transfer or booster port to be used.If that gear box for reduction is the same as mine they are multi geared not chain or belt drive on the E108 but mine is getting kinda old now so not totaly sure on that.
 
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