Jetting, WR426, 02, Stock

Been having problems with my bike ( Jetting I think ) Runs fine in low gears and :) 1/4 to 1/2 gas but If I giver real hard ( shifting fast and let off the gas it back fires or when I'm in fith it's sort of boggy and will back fire.

I pulled my plug and it was black with some sout on it.I have tryed to adjust my fuel/air screew and it made a little differents.

Black plug means to rich "right"

The stock jet was 165 so should I try a 160 to see what happens ??

Oh I live in Ontario so I prity close to sea level


Backfiring is a sign of being rich. What needle and clip position are you using? you may want to Try raising the clip or dropping the main to a 162.

Try Taffy's setup for his bike. He has put hours..if not months into research and according to almnost everyone who has tried it, they say it is the best setup going! :)

Try Taffy's setup for his bike.

OK but who or what is Taffy's and how do I hind that setup.

I thought I would drop two sizes on the main to see if it made any differance and then try a 162. :)



Taffy's jetting is in his signature. If you search in jetting Qs you will find alot of his work. Also there is a post running now, "Taffy & LarryCO Jetting" that has some good information. Good luck.

Put the 160 main jet in and took it out last night. Went OK but I think I lost something in the low gears 1/4-1/2 throttle. Dealer didn't have a 162 MJ in so I will order one and try that. :)


try lifting your needle one clip for now to richen it.


I'm going to hold off till the 162mj comes in and then try that before changing my clip. I will let you know :)

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