WR426 JD kit jetting help please James Dean


5 replies to this topic
  • taylorworld

Posted April 12, 2007 - 12:21 PM

#1

I’ve done a search but can’t find what I’m looking for. I have a 2001 WR426 with a YZ426 exhaust, YZ timed, air box lid removed, YZ throttle stop, and grey wire unplugged. I installed the JD kit as directed but can’t seem to get the bike to rev out like I think it should. I started with the 170 main jet and then went down to a 168 but it didn’t seem to help it at all on the top end but the midrange seems effected when I changed down to the 168. I ride around 1500 feet above sea level in east TN. Should I go even smaller with the main jet?!?!

  • 02WR426Cali

Posted April 12, 2007 - 01:38 PM

#2

I'd go with the 170 if you never go higher than 1500 ft. I have the same setup except for the yz timing (haven't tried that out yet) and I run a 170 from sea level to over 3500 ft. with no problems. I also put in a 42 pilot jet (I think that's what it was, 1 size bigger than stock whatever that is) and I used both needles that came with the kit and didn't feel any difference between the two. S I chose to go with the red with the clip in the middle position. Runs great.

  • wwjam

Posted April 12, 2007 - 03:14 PM

#3

Year: 2002
Model (400 - 426 - 450): WR426F
Cam Timing (WR/YZ): WR
Main jet: 170
Pilot Jet: 45
PAJ: 75 stock
MAJ: 200 stock
Leak Jet: NA
Starter Jet: 65 stock
Fuel screw (turns out): 1.5
Needle Model/Clip position: Blue JD needle 3rd position
Grey Wire Mod (Y/N): Y
TPS Connected (Y/N): Y adjusted to specs
Airbox Snorkel/Lid (on or off): off
AIS Removed (Y/N): NA
Airfilter Brand: UNI
Exhaust Brand: WB E2
Average Altitude: 0-1000
Average Temperature: 60
Average Humidity: 80
Degree of Satisfaction (0-10): 10
Additional Mods/Comments: Thin JD O-ring used on accel. pump linkage
Lots of low-end grunt and power everywhere on the RPM range.
No more hesitation or missfiring at cruising speed (TPS adjustment fixed that)
___________________

This is my setup and it works great from 0-1000ft.
You should be ok with the 170 main
Other things to check
TPS adjusted correctly
Float level
Spark plug gap
Valve clearance

It also helps to periodically remove all of the jets and flush out the carb (both fuel and air passages) with carb cleaner and then compressed air.

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  • taylorworld

Posted April 13, 2007 - 05:27 AM

#4

thanks for the replies guys! but keep them comming! i was hoping James Dean would chime in sometime also. i tried it out again last night by adjusting the fuel screw and got it a little better throttle responce i think. the bike is in tip top shape so the only thing it can be is jetting as far as i know.

  • SXP

Posted April 13, 2007 - 06:36 AM

#5

thanks for the replies guys! but keep them comming! i was hoping James Dean would chime in sometime also. i tried it out again last night by adjusting the fuel screw and got it a little better throttle responce i think. the bike is in tip top shape so the only thing it can be is jetting as far as i know.


PM James directly. This is a huge site and to expect him to peruse all the threads is asking for a bit much, don't you think? He has ALWAYS replied to my PMs within a day or two.

  • clark4131

Posted April 13, 2007 - 07:41 AM

#6

Your thread has been copied to the Jetting forum. You'll likely get JD to answer directly...SC




 
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