YZ Muffler on my WR426-CAN ANYONE HELP?

Just put on a 02'YZ426 muffler onto my WR426,just wondering if anyone is riding with the YZ muffler

on their WR's.I'm still with (bone stock jetting).

It started no problem,then had to adjust the idel up a bit.It ran fairly strong and notice it to be more responsive-compared to the stock Wr muffler!

When coming back down(decelerating)it bogged alittle and then stalled.Took a while to get it fired up,rode back to my house,while trying to make it backfire,gasing it-then backing off,seemed

to run fine,no back firing? Question is should i go richer or leaner? I think it's to rich-pilot.

Anybody with this set-up have any suggestions?

Thanx Mike

[ May 17, 2002: Message edited by: BigDesto ]


Glad to hear you got the silencer on the bike...Hopefully someone will reply in regards to your jetting question.


Jeff, rode at the track today and it wasn't bad at all! :) It hits alittle harder and is more responsive,not to mention the weight i'm saving over a stock wr muffler.Everything is still stock jetting,seems to run great,just think i can lean it out alittle more?

Thanx!! Mike

You can look at my settings and decide from there which way you might need to go. I find it kinda hard to imagine your bike is still running rich. Perhap's it's the stock needle thats the difference...


Hey Socal, I was just wondering if i should set-up the jetting like a YZ? Right now everything is stock,i haven't even adjusted the air screw or anything yet.I'm kind-of glad that i didn't have to change anything! I can put the stock wr muffler on whenever it needs to be legal. Have you been to piru mx yet? Let me know when you head out and maybe i can meet-up with you out there. What are you like less than 5 miles to the track?Must be Nice. I've been there 3-4 times already!

I don't think (unless you are R.C in disguise) you can really use all of our power range to really get a good judgement of jetting at PMP, The set-up I'm useing works well at sea level and I've been up to 5000ft + with no problems, unless I run my twin-Air filter. Then every once in a while I start to foul a plug in the real slow stuff, lugging and throttle blips, but clears out when doing higher speed stuff. I too was at PMP last Sat also, you couldn't miss me! I was the guy coming into the pits every 3 laps to massage out my arm pump! :) I was crying!!


Oh yea! I'm useing a 00 YZF needle droped to 3rd or 4th notch.. aaaw 2nd from the top.

[ May 20, 2002: Message edited by: SoCalWR426 ]

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