Intermittent Missfiring

Vfrog

New member
07 CRF 250 X Recently installed a Athena 280 big bore kit and a Hot Cams Stage 1 cam, a new Trail Tech Stator with Reg/Rec and a new cut off switch that allows me to also turn off the headlight. Also installed a Recluse clutch. The Trail Tech stator kit was brand new everything else was used.

I went for the first ride last Sunday and all was great. Better than great

I went for a good long ride today starting at California Rd / Triple Tower / Just Dandy / The Eliminator / M&M / Forbidden Planet.
Along Forbidden Planet my bike started to miss fire intermittently. Ran back to 511 down the road to Triple Tower and back to my truck. On the way back it seemed to clear up then started again.
When I got back I checked all the connections to the new stator and even drained the oil to pull the cover to have a visual. I am presuming it is the stator, or ignition system side.
I did pull the spark plug and it looked good but tried a new one as well. No change.
It feels like an electrical issue. It is more pronounced when the engine is loaded.
I did install a new kill switch as well so that is another option to check but it does not feel like that would be the issue. It can quit at idle sometimes and then starts right away.

Any help in how to diagnose this would be appreciated. I like to do my own wrenching to learn about the bike.
If it is not simple I may need to take it to Woody, but am scared it will come back painted Orange!!
 

rackatttack

New member
I'm thinking that with all the mods you have done its time to go back to basics.
did you clean the carb? if so good if not then a few things may be happening ( float level may be off , pilot might be plugged slightly , accelerator pump maybe miss adjusted)
what I have seen is when going to a big bore kit is the jetting needs to be leaned out a tad start with your idle and pilot and ac pump taking notes as to what you have done then work with the needle (I know it a pain in the buttoski on the Honda) then finally on the main (this you may not need to change ) remember do one change at a time
 

Vfrog

New member
No I did not clean the carb or change the jetting. The first ride the bike felt great with lots more grunt. The same with the second ride till it slowly started to mis fire.
I have been in contact with Trail Tech today on the stator. After starting it goes way out of spec on the resistance measurements. They say the stator is bad. They however will not send one under warranty until I send this one back and they confirm my readings. Still talking to them.
 

Vfrog

New member
Trail Tech have verified that the resistance readings should not increase as the stator coils heat up. They say that one in 1,000 do this so they are sending me a new one. They just had me show that I cut the wires off the first one. Hopefully a new stator will solve the issue. Would there be any chance of the bad stator damaging other electrical on the bike?
 
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