I just put a Uni filter on my ex. That is all I have done to it for now. I just wanted a filter that flowed a little better, but still had good protection. My question is do I need to rejet, or possibly adjust a little richer? Seems to run fine but I have heard that the 400ex's come borderline lean from the factory. I was going to wait to rejet until I get a slip on, but want to ask the experts first.
Thanks.

<< I just put a Uni filter on my ex. That is all I have done to it for now. I just wanted a filter that flowed a little better, but still had good protection. My question is do I need to rejet, or possibly adjust a little richer? Seems to run fine but I have heard that the 400ex's come borderline lean from the factory. I was going to wait to rejet until I get a slip on, but want to ask the experts first.
Thanks. >>



Normally, with only the addition of an after market filer, rejetting isn't needed providing the engine is not in a lean condition to begin with. Therefore, it seems to me your real need is to determine whether or not you were already lean before adding the Uni filter. You'd do that of course, by running a thorough test ride &amp; plug read. After all is said and done, that's the only real way to know.
By the way, your question, &quot;should I rejet or just adjust a little richer?&quot;, is puzzling. The only jet which can be adjusted is the needle jet which operates in the 1/4 to 3/4 part of the band. Until you verify that anything is needed in rejetting, I'd leave the needle in the nominal position of three. In doing any rejetting it's always best to jet for the 3/4 to full throttle part of the band, first.

Sorry for the confusion. I meant should I rejet the carb (basically main jet) or try adjusting the carb richer (air/fuel screw). I will do a plug read to see how it looks.
Thanks.