# upgrading piston for 80cc engine



## lmt23 (Aug 23, 2005)

Hi, I'm thinking of upgrading a performance piston on my 80cc bicycle engine. I only go up to 28 mph and unsatified. I want it to go around 40. So far I found these websites that sells the piston for two stroke 
http://www.motocarrera.com/piston.htm 
http://motoxdepot.com/wi80pikit2bi.html <== this on fit on 80/85cc?
and how would I know if the piston will fit inside the cylinder? And what is to bore the cylinder. Could anybody help me? Thanks


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## bugman (Aug 12, 2004)

first off, if its made for a 80 cc, it should fit, but the manual if you got one should state its stroke. why do you want to go faster? this is after all a bicycle right? your only asking for problems, especially you and whatever you hit going 40.....on a bike.... also a performance piston really isn't going to help you go faster, gearing will though.


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## lmt23 (Aug 23, 2005)

Thanks Bugman. I think 30 is enough problems when I hit something. Thanks man. Hey will this work on the bicycle http://www.thesuperkids.com/nigtsux2ctr.html


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## lmt23 (Aug 23, 2005)

htt


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## bugman (Aug 12, 2004)

maybe, if its made for it, though about gearing, you know how mountain bikes are?


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## lmt23 (Aug 23, 2005)

What do you mean by how mountain bikes are? Do you mean the frame of mountain bikes are not meant to go any faster then human power? So far when I max out the throttle the front fork of the bike shake violently which was really scary at first but not anymore. I will going to upgrade that with a front fork that has suspension for about $25 on ebay? 
The CVT transmission, that I have to do more research on that to see if it will fit to the mountain bike frame. The reason I want to go faster is because I actually want to ride as fast as those 50cc $1000 scooters (max 45-50mph and they have CVT tranny) so I can merge with cars on the street not riding on the right side of the street and side walk and not cars pass by. In addition I'm taking small engine class and a welding class in the local occupational adult school for free with 14 semester units of university classes aside. I plan to take my motorized bicycle to school and riding on the sidewalk halfway takes forever to get there. Thanks


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## bugman (Aug 12, 2004)

reason why i mentioned mountain bikes, thier gearing.... of sorts, if the tranny will fit, and work, great thing to have.... :lol: i see those tiny little chopper wannabe weedeater engine powered scooters, pretty funny to look at, but get good gas mileage!


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## Lit_Match (May 29, 2006)

I have the same engine. The 80cc is more than enough power, you just have to give it what it needs to run. These kits come with a small carb, 12mm I think, get the intake manifold bored out and get a bigger carb (17-18mm range). Get a custom exhaust pipe made, the one that comes with the kit doesn't even match the exhaust hole in the engine. After this your engine will have reached its potential, you put this extra horse power to use by having a custom rear sprocket made (the disk that is bolted to your back wheel). You either have a 50 tooth, or 44 tooth rear sprocket, you should have a 36 tooth made, you will gain enough speed to be scared to go any faster (at least on a bike). Final note, if you do this I can't stress enough that you should upgrade your brakes, wal-mart sells disk brakes for bicycles, get one for the front and rear wheel and you should be fine.


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