> Dan Church Wrote:
> -------------------------------------------------------
> The stock airbox has no filter inside, and
> apparently they are no longer available.
On that air box assembly, should there be anything else inside the box other than the foam filter? I had an Express with the same symptoms. Turns out there was supposed to be little frame in the airbox holding the filter a short distance from the carb intake. Air was to pass over the entire rear side of the filter, exit the entire front side of the filter and then be drawn into the carb. (there is a short distance from the filter to the carb - 1/2", 1", ?, I don't remember). Without this little frame to maintain that space between the exit side of the filter and the carb, the increase in air velocity as engine speed increased would draw the filter up tightly against the carb. At this point, instead of air coming across the full face of the filter (what, 3" X 4"?), you had air coming across only at the opening of the carb (what, 1-1/4"?) - not enough air. I made a little frame device out of a coat hanger and solved my problem. p.s. look up the airbox assembly online and see if you are missing anything. (edited)