I'm new and I don't own a bike, but I found this in the KLR FAQ's and Helpful Links thread.
"Why is my bike running poorly?
Start with these:
Clogged pilot jet
Crud in float needle valve preventing closure (or full flow)
Torn carb diaphragm (usually midrange running problems)
Plugged carb vent hose (do the T-mod)
Plugged gas tank vent preventing creating a vacuum in tank (stalling/starvation on highway) Drain hose is full (the ones with the caps/reservoirs; drain and recap)
Vacuum line to petcock is collapsing when it gets hot, causing fuel starvation
Inline fuel filter (aftermarket) is restricting flow (the in-tank screens are usually pretty clean)
Gas boiling in fuel line (if it's very hot out, generally over 100-105 deg F, and if side shroud vents are covered)
Valve clearance at limits"
Last edited by moreair; 08-08-2011 at 12:09 AM.