125cc running wierd

[Jay_wolf]

all of a sudden it hesitates and backfires past 4000 rpm , it just stutters and bogs , i pulled the carb ,. and it all looked fine from what i saw . any ideas?

[seamax]

have you pulled the plugs...I pulled mine recently after my bike stuarted stuttering and one of my plugs was rich. Adjusted the fule/aire mixture screw and put in new plugs.

[Jay_wolf]

Yep, its a single , so just the one , its a lovely tan colour , my thought was a weak plug

[seamax]

have you put a voltmeter to the coil?

[yamahonkawazuki]

all of a sudden it hesitates and backfires past 4000 rpm , it just stutters and bogs , i pulled the carb ,. and it all looked fine from what i saw . any ideas?

Hey jay does this bike use breaker point ignition? or check whatever would trigger the coil to fire. and see if itcould be at fault