I have been chasing around a surge in my recently aquired XR600. I thought it was a lean condition, so I went and got some richer jets. It has the same surge and poor running charactersistics after using a broad spread of jets. Today I put it back to how I got it; still popped and missed with a little black exhaust. I then lowered the needle from the 3rd to 2nd(from top) position, and it got worse. Here is a link to my post in the jetting foum: '95 Lean Jetting I am trying not to have tunnel vision and focus only on the carb. Now that I've ruled alot out plus my bike's unresponsiveness to jetting changes, I am frustrated and figured I'd ask in here for any possible XR600 nuances I may have overlooked.