rough choppy sputtery acceleration 1/8 to 1/2 thro

4 replies to this topic
  • SCteck

Posted December 12, 2003 - 07:24 PM


Help I have an 01wr426 that wont accel smoothly.
Full throttle power is great.I know its gotta be jetting.
does anybody have a good combo to run with
Open Airbox
Stock pipe /vortip
What exactly does the grey wire controll?

  • tctrailrider

Posted December 12, 2003 - 07:52 PM


1/8 TO 1/2 throttle would be effected by the needle. If its missing its probably rich. If its missing, surging, with pops and maybe a bang its lean.
Have you changed anything, is your fuel fresh? If it ran well before and the current temps. are lower you are probable lean and should raise the needle a clip. Raise the needle by lowering the clip.
The gray wire is a ground that effects the ignition timing. The WR has it the YZF does not. Some disconnect is and like it, others don't notice a difference. Read this
The mods for the 250 and 426 are the same.

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

Posted December 12, 2003 - 07:58 PM


Help I have an 01wr426 that wont accel smoothly.

Try to pinpoint the throttle position relative to the rough running problem you are having, if it is a jetting problem then this will help identify the jetting circuit in the carb that is responsible. If it won't accelerate smoothly when you really whack it open it may be clip position.

But once you ucork (the exhaust) and uncover (the airbox) the motor is way more YZ than WR, and IMO should be jetted accordingly. If you have $14 to spare buy an '01 YZ needle and try it on clip 4 (you should also try a 165 main). Based on my own experience w/ WRs you will be impressed (don't mean you will like it, but you will notice the difference, I promise).

The grey wire will also make a difference but it is subtle compared to the problems you seem to be experiencing. IMO. I think that cutting the grey wire alters the ignition timing curve in some way, not sure (anyone?).

If you want to experiment for yourself I'd suggest dropping the clip one notch and seeing what kind of diffrence that makes, but I still stand by my statement that you will prefer the way it runs with the YZF needle, regardless of the source of your problem.

Hope this helps.

  • captain_S

Posted December 13, 2003 - 12:17 PM


If you mark the throttle grip and cable housing for throttle position you will find this to be a great help when trying to judge where in the throttle range your problems are!,to do this mark a line on the grip and housing for closed position,then twist to full open position and mark a line on the housing next to the line on the grip,then repeat for 1/2 1/4 3/4 throttle positions,it takes away a lot of the guess work! :)

  • SCteck

Posted December 13, 2003 - 05:21 PM


Nice thats a good idea..Im nervous to try and start changing my carb all around for fear I'll forget how it ran with what in it.So many diffrent combo Possibilitys....But as for pinpointing my problematic throttle zone your suggestion is great thanks.


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.