WR426 cam timing / jetting

I am new to the forum here, but i have always read the discussions from time to time and decided to change my WR426F over to the YZF cam timing. The jetting that I had prior to the change seemed to be OK. I was just wondering if I would need to re-jet and maybe what others have jetted their bikes to. I live in Colorado in Ft. Collins and haven't gotten to ride it since our huge snow storm to see how it seems to be jetted. Thanks again!

I yz timed my wr about a month ago, and I have not changed from my stock jetting yet. I have ordered yz spec jets but I have not installed them. It runs so well right now that I can't imagin it getting better, but Ive been told that it should be leaned out after the yz timing change.

I will post my results.


My bike is set up pretty much the same as yours but I have left it WR timed. Jetting is stock. Raised the needle one clip (5) and went in a bit on the fuel screw. The bike runs fantastic at all throttle positions. I have an ELN needle and other jets but it runs so good I won't mess around with jetting (at least for awhile). Most of the jetting experts agree that going to YZ cam timing does not effect jetting. I think the open airbox and open pipe need the richer E taper, YZ jetting. I run the Baja designs vor tip at sea level and wonder if the E taper might be a little rich with the insert in. Good luck with the search for perfect jetting.

If you read my recent post on this subject

HERE you will see that changing to YZ timing definatly affected my bike.

Changed it back to WR last night and it still ran like crap, so I put in a new plug and it purred like it always had. So YZ timing definatly affects jetting in my book.


Seems to me that if you changed to YZ timing and it ran like crap, changed back to WR timing and it still ran like crap, changed the plug and all is well. You had a bad plug during your YZ timing run. Don't think you should draw any conclusions other than the plug.IMO

See my sig for good CO jetting...

Dont have an opinion on jetting affects based on YZ/WR timing changes...havent changed mine...havent found a need to now that it's jetted well.


Thanks to all of you for the advise I appreciate it. I think I will give it a ride and see how it goes. I think that I need to go a little bit bigger on my main jet anyway. It was just a tad lean before cause the plug was looking a little to white. Anyway thanks again!

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