Jetting, Plug Fouling, Check Valve - FINALLY

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

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