pit bike runnin rough... fuel mix problem??

[clynt]

hey guys im havin a few problems with my bike. its a 200c lifan with a standard kei hin jap carby on it. i thought it might have been out of tune so i had a play with the idle n also the air/fuel mix n it didnt really change. atm i have it idling very low as at times the idle will jus randomly increase to a hi rev.
it cant increase in revs quickly when riding, yesterday i took it out n the only way i can get revs up a bit is by increasin slowly until it starts to choke. as soon as i pull the throttle it will cough an splutter, shoots flames occassionally and also backfires as loud as a gun.

i have played with air/fuel mix and idle and taken air filter off and replaced with new one. this has changed nothin in the performance of the bike. any help from u guys wud b great!! thanks.

 

[146cc_outlaw]

you may have an air leak in between the manifold and engine or manifold and carby make sure you check all bolts on these bikes as they do come loose from time to time try that and see if it fixs it if not it maybe your timing but for now just do a basic check on all bolts

 

[clynt]

you may have an air leak in between the manifold and engine or manifold and carby make sure you check all bolts on these bikes as they do come loose from time to time try that and see if it fixs it if not it maybe your timing but for now just do a basic check on all bolts

i put on a brand new mikuni 30mm carby today and tightened all bolts in that area, still doin the same thing although at when in neutral it allows hi revvin n has quick response, its only when ridin now that it chokes n backfires etc. when at idle it sounds like it misses as well? could this be spark plug?

 

[146cc_outlaw]

sounds to me that you need to do up the spark plug as there also come loose and therefore loose compression as i said check ALL BOLTS ON THE MOTOR and go from there and also check all the wires on the coil and cdi are tight

 

[clynt]

sounds to me that you need to do up the spark plug as there also come loose and therefore loose compression as i said check ALL BOLTS ON THE MOTOR and go from there and also check all the wires on the coil and cdi are tight

ok then ill give that a go tomorow n let u know how it goes. thanks

 

[Metalmulisha 110cc pro]

Could be your valve clearances just cheak what thou they on because they could be leaking.