My motorized bicycle's engine seriously lacks power, and I feel I've done everything I can

21nafin

New Member
Sep 2, 2021
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Belmont, New Hampshire
I have an 80cc unbranded Chinese bicycle motor. When I first got it it was working fine. I eventually upgraded the carburetor to a racing one which seemed to work fine. Later, it started seriously lacking power to the point where it wouldn't go up the smallest of hills. I even hold the clutch in and rev the engine and it doesn't rev nearly as high as it should. I've cleaned the carburetor, adjusted the throttle, cleaned out the exhaust (even tried running it without an exhaust and still had the problem,) replaced the spark plug, and even replaced the engine. But I'm still having the problem. It's also worth noting that now it won't even idle even with the idle set as high as it goes. What could be my problem?
 

wrench

Well-Known Member
Aug 20, 2019
329
298
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So Cal
You really didn't say how long ya had the new carb on before the engine started acting up.
All's ya said was "it SEEMED to work fine"
Try using your old carb and see if it improves
 

21nafin

New Member
Sep 2, 2021
4
0
1
21
Belmont, New Hampshire
You really didn't say how long ya had the new carb on before the engine started acting up.
All's ya said was "it SEEMED to work fine"
Try using your old carb and see if it improves
It worked fine for well over 2 months, and the old carburetor is defective (that's why I replaced it)
 

wrench

Well-Known Member
Aug 20, 2019
329
298
63
So Cal
What you describe sounds like a compression leak, but you say ya have the same problem with a new engine, so IDK.
Maybe a faulty CDI keeping the RPMs low?
 
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