not getting enough power out of my new 66cc new engine plz help?

[joshua97]

hi i just finished my 6th motorized bike, all of them have used similar 66cc engines. This engine is an F80 66cc ( 3rd one i have had) they are not the best quality i know lol but i run them through 40 tooth sprockets and with the baffles removed from the exhaust. they all do around 46 to 51 kph. except for this new one with the same setup as previous i only do 38 kph.... I have used other new carbies and still have the same problem. The engine just finished the 500ks run in period and has awesome compression. please help me with any tips at all, thanks josh?

 

[Fabian]

Be thankful your engine only does 38 kph. An engine that pushes your bike to 51 kph makes the hurt from the hurt locker harder to cope with when you hit the ground and it will only get you into trouble from the law.

My 66cc engine does around 25 kph.

 

[joshua97]

haha thanks mate, that is true

 

[Deleted member 12676]

porting can be different in different engines due to loose manufacturing tolerances. Compare the deck height between the dog engine and a good one. More deck means lower ports which means less port open duration which means less top speed. You can add another base gasket to compensate but then you have to remove the head gasket after planing cylinder and head mating surfaces on sandpaper/glass and then use a gasket making silicone and let it dry before using.
Could be differences in the CDI.
Could be crank seals leaking. Sometimes a visual inspection reveals a poor seal. They can be replaced without splitting the cases.

 

[wally]

Plug colour? Running too rich? Four stroking? DON'T run too lean, rich is better than lean. Lean burns and seizes things not nice.