motor runs for a block then wont accelerate

j2thevvizo

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Oct 20, 2009
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my bike is giving me problems. its struggles to start up sometimes but eventualy it starts and i ride for a block or two and the all of the sudden it wont accelerate any more. the motor is still on and it just doesnt go when i twist the throttle. i stop and try to start it again and it struggles to start but then eventually it fires up and rides for a few blocks and doest it again. ive never had a problem with the engine until now. its always been fine. i thought it was the throttle but the cable seems to be pulling the valve side in the caburator properly. im thinking that it may be a spark plug problem or too much fuel is getting into the combustion chamber and its flooding. any ideas would help. thanks
 
it could be running too lean and starving for gas. i find this problem alot with my nitro powered R/C cars, loss of power and run hot in a lean condition. same with my gas trimmer. a simple carb adjustment could make all the difference in how it runs.
 
ok ill try. that means that i have take out the carb pin and put the little washer on a different notch. which way do i move the washer to make it less lean? thanks for the reply
 
my bike is giving me problems. its struggles to start up sometimes but eventualy it starts and i ride for a block or two and the all of the sudden it wont accelerate any more. the motor is still on and it just doesnt go when i twist the throttle. i stop and try to start it again and it struggles to start but then eventually it fires up and rides for a few blocks and doest it again. ive never had a problem with the engine until now. its always been fine. i thought it was the throttle but the cable seems to be pulling the valve side in the caburator properly. im thinking that it may be a spark plug problem or too much fuel is getting into the combustion chamber and its flooding. any ideas would help. thanks

If it was previously OK and you haven't changed anything, then you shouldn't need to change the slide needle setting.
You've cleaned or swapped the plug? If not, that's first.
It sounds like it might possibly be starving for fuel, from fuel not flowing into the float bowl quickly enough. It wouldn't hurt to disconnect the fuel line at the carby then turn the fuel petcock on and see if you're getting a decent fuel flow. The fuel filter may be blocked.
If that's OK, pull the carby off and clean it, ensuring nothing is blocked.
What colour is the plug? If it's starving for fuel the mix will be lean so the plug will be dry and light coloured. If it's rich or flooding, the plug will be black. If the mixture is OK, the plug will be a tan colour.
Let us know how you go.

... Steve
 
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I was also going to suggest replacing the fuel filter and make sure the air filter is not plugged up. a plugged air filter will make it run too rich and bog.
No carb adjustments should be needed if it has always ran good and he didn't change anything on the motor.
but, it could be that the jet needle c-clip was set to make the motor run on the leaner side and ran fine in warm weather. not sure where he is located, but if the carb is set on the lean side, and he is now running in colder weather, it could be too lean now. colder air will make it run leaner...just a thought.
to richen the carb, move the jet needle c-clip down from the top(which raises the jet needle allowing more fuel to flow through the main jet). to lean it, move the c-clip up (which lowers the jet needle into the jet, allowing less fuel to flow through the main jet). the more the jet needle is inside the jet, the leaner it will be. by moving the c-clip up or down, you raise or lower the jet needle.
 
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I recently installed my first 80cc chinese kit on a mountain bike, I had the same problem, the engine started, then after few meters would stop....

Then I realized that I installed the carburator on the wrong side (up-side)

THe black plastic tubes for air intake should be downside, than worked wonders

SO maybe your problem is the carburator, or something related with air-intake
 
Then I realized that I installed the carburator on the wrong side (up-side)
THe black plastic tubes for air intake should be downside, than worked wonders

You actually got it running with the carb upside-down for long enough to do a few metres? That's got to be a first. Well done!
Maybe that's j2thevvizo's problem.

... Steve
 
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You actually got it running with the carb upside-down for long enough to do a few metres? That's got to be a first. Well done!
Maybe that's j2thevvizo's problem.

... Steve

Like 6 meters hehe, Im a newbie, giveme a break lol
 
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