WR426 cam timing / jetting

6 replies to this topic
  • danno426

Posted March 25, 2003 - 05:54 PM


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!

  • darmino

Posted March 25, 2003 - 09:49 PM


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.

  • tctrailrider

Posted March 26, 2003 - 04:55 AM


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.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • MOmilkman

Posted March 26, 2003 - 06:01 AM


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.

  • tctrailrider

Posted March 26, 2003 - 06:40 AM


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

  • LarryCO

Posted March 26, 2003 - 10:29 AM


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.


  • danno426

Posted March 30, 2003 - 06:59 PM


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!


Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.