Burned: Help for WR250 jetting?

[jrnymn89]

I recently purchased a '03 WR250 with the following mods:

Yoshi pipe/header, YZ exhaust cam, Barnum airbox mod, p-38 and Zip-ty pilot screw.

my settings are: Main jet-#185, Pilot jet-#40, Leak jet-#90, Stock needle (groove #4)

I ride at 0-500 foot elevation @ 60 to 70 degrees. Could you recommend a good jetting set-up? Also, I checked the pilot screw and found the o-ring, washer & spring missing. The screw was only 3/4 turns out. Can you recommend a starting point (turns out)? Thanks for your help.

[WheelsUp]

I'm running a JD jet kit with the blue needle on 4, 182 main.

Drop your leak jet down to a 40 to help your bog.

My pilot is a 45, and the ZipTy screw is out 1.75 turns.

On the stock needle, I think a 185 is too fat, but your '03 has a different needle than my '05, so you may be okay.

With the #40 pilot jet, you will likely have to turn the ZipTy more than 2.5 turns, which can cause it to vibrate out on the trail.

[Wayward Son]

how does the bike run currently.

[jrnymn89]

Runs OK but pops alot on decel. Will not stay running at idle and sometimes stalls with closed throttle while riding.

[Wayward Son]

that is a pilot jet issue.

try bumping the pilot jet to a 42 or 45 like wheels suggested.

[barton]

Yup, I ride similar elevation, with similar weather in the spring, and have an 03 WR with JD kit, YZ exhaust cam, YZ exhaust and a Zip-ty screw.

I found the 185 main jet a bit rich, so I run a 180 in the summer, 182 in the winter.

In the summer I run the blue JD needle on the 4th clip position.

My pilot jet is a 42.

Leak jet is a 40.

Fuel screw is adjusted so often I don't even keep track of where it's at anymore. I believe that I'm usually 1.25 - 2.25 turns open. I spin the idle up 1/2 a turn, adjust the fuel screw by ear, then return the idle to normal (~1900 rpm).

[jrnymn89]

Thanks guys. That should give me a good start.