2004 Yamaha Warrior 350 No Spark

[RevNate]

Trying to help a friend with his 2004 Yamaha warrior 350... It wasn’t getting a spark so we replaced the spark plug, cdi box and coil. Have tested the kill switch, checked fuse,  everything is good there. Monday (8-20-18) we installed a new stator and got spark, ran it around my trails for about half hour then put it up. Today (8-25-18) we went to go riding and it wouldn’t start, again getting no spark... can’t wrap our heads around what happened when we got spark back then a few days later nothing... any help would be greatly appreciated 

[Oldymf]

Have you checked all of your grounds ? I would look for loose, dirty, or even cracked wires that could have corrosion inside.

Edited August 26, 2018 by Oldymf

[RevNate]

I will check through them, just real strange that we had spark, shut it off and then a few days later no spark again...

[Oldymf]

It could be a loose or breaking ground. They can be like chasing a ghost. Just check them all. Look for dry rotted cashing.

[johniii]

Maybe the spark plug boot is bad, its possible for it to be shorting out,more like an open .

[Samuel “Sam” Frady]

If I was plug boot you would see "lightning tracks" on the boot it's self. My suggestion other than grounds as suggested previously (best way to check would be ohm meter from grounds of the cdi, coil, and engine case to battery negative post) would be to trace wires to the stator and make sure that there is not anything rubbed through especially where it goes through the case. Also I have had solder on the stator contacts get hot and degrade eventually coming appart especially with cheap stators.

P.s. also check ground of engine case while trying to start if stator shorts internally it will sometimes give alternating ground/positive as engine turns

[Admin]

Topic moved to Yamaha ATV Forum and added ATV info into topic title. 😁