i have recently done a engine change on my 50cc speedfight but it seem to be giving me problems. its like when i try to pull off theres no power there then it finally takes off but as soon as it gets to like 20/22mph it dies a bit and stays at that speed.

plzz could someone give me advice

Tyronee, February 2011

okayy thanks guys, i have my old variator and rollers from my other engine and it did run fine with this exhaust. so would it be easier to put that variator on?
Jet are not blocked i have cleaned my carb out. But shall i put the jet out ov my old carb in the the carb thats on my bike now?
ohh yes i remeber now wen i bout the engine the guy offerd me the exhaust that was off the engine and it was a stardard one but i didnt take it :s

Tyronee, February 2011

what type of exhaust does it have on it ?i would guess that you have an expansion chamber race exhaust on it ?if so then the problem is the rollers in the variator are not light enough to create enough revs to get the backpressure in the exhaust high enough to make the engine run right !its a typical problem with these type of pipes im afraid put a standard one on and it will be fine.

adam bike doctor(of milton keynes motorcycle centre), February 2011

check jets in carb are not blocked

rayb, February 2011