Jetting, Plug Fouling, Check Valve - FINALLY

No replies to this topic
  • Tony_Miller

Posted May 06, 2002 - 07:57 AM


My bike finally screams without fouling plugs. The thing was fouling plugs every ride, but it seemed to run lean in places so I was hesitant to richen the carb anymore. Then I heard about the gas cap vent line check valve being a possible problem, and a little light bulb went off. I started fouling plugs when I started riding more with my wife. We would go on generally short rides that did not require me to top off my tank. With that air in my Clarke gas tank, the engine heat turned the tank into a pressure vessel! Took out the check, and voila, tan plug! I was able to go a little richer on the main jet and WOW, instant throttle response, front wheel goes straight up! So here's where I'm at:

1998 WR400
1000-1500 Ft
60-70 Deg
Removed air box lid
YZ timed
cut grey wire
FMF Q-series silencer (stock header)

48 Pilot (pilot screw at 3/4-1 turn)
DVP needle clip #5
180 main jet
rest of carb - stock


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.