Originally Posted by slide
Can it be a vapor lock, paul_g? How hot is it where you are?
As to lowering rpm, changing the cs sprocket is the standard way to do this on bikes in general. I have no idea why this won't work on the x-c
scratch that, reverse it. Of course I meant raising rpm's but I think you followed my gist. That doesn't seem like the right solution after all, because it isn't consistent.
you know, I wonder if it happens to receive a lot of direct sun if that could cause it? A Vapor lock as you describe?
I am at 7000+ feet in northern NM. Our summers don't get much above 88 tops.