I have a 1997 Yamaha WR-250 that I just can not get jetted properly using OEM parts.
My primary objective is to get it so that it will quit fouling plugs every ride. It does OK if I am on it, riding hard like when I am riding an enduro. When I ride easy, such as when I am riding with my wife or nephew, I will foul a plug every time. I don't dare take off without bringing a spare plug along.
I have already changed the main and needle jets to the smallest size I can get from the dealer. I have the needle in the top most clip position, which lowers the needle as far as possible. I am running synthetic oil, 40:1 mix ratio. The plug is a BR8EG.
What surprises me the most is that I have made what I would think are dramatic changes in the jetting and I have not noticed any significant change in how the bike runs. It can be a bitch to start, especially hot. It will idle reasonably well, but if I let it idle to long it will foul the plug.
I have tried looking at the JD jetting website for an after market solution but they don't offer anything for my bike and the carburetor is different than what the YZ models used.
I have tried various float levels. The Clymer manual I have for my bike has totally bogus specifications for the float level, there is no way the number they provide is correct.
What do I do now?
Rod