Repairing atv. Fixed fuel problem. Engine starts fine at idle, press accel engine falls on face.
Spark test w/expandable gap no problem at idle. Rev up and spark goes erratic causing engine to falter. Started engine again today, revs fine like no problamo. Generator,cdi pack,
or coil?
How does one fix???????

 

I was going to say clean the carb first,but if you know its the spark, I would try the coil fist,its cheaper and easier and if it was the Stator/Gen or CDI I think you would have no spark at all.

The 350 Has a Pulse/trigger coil next to the flywheel, its magnetic and catches small filling after awhile and could need to be cleaned and re gaped. Happened on my my Polaris same set up. Un like Polaris,if it is the pulse coil Yamaha does not sell it separate but wants you to buy the entire Generator!