1983 honda cm 125 starts but wont run?

Sounds like you're getting too much air and not enough fuel. I agree with what advice rayb says. You could also block the majority of the air intake with your hand and see if it will fire up, if it does try giving it a bit of throttle (still covering most of the air intake with your hand). If it runs better then that's your answer. Try a new air filter and setting the fuel/air mixture again. New spark plugs would probably benefit your bike as well. Hope this is of help to you and good luck. :o)

John
July 2011

could be fuel problem. strip carb.and check main jet for blockage.

rayb
July 2011