I think the video does the best job of explaining. I sincerely appreciate any suggestions. It's great weather to ride in Oregon, and the trailer hitch for my car will be here tomorrow so I gotta get my trusty XT sorted out. <iframe src="//www.youtube-nocookie.com/embed/__V3lj6Asno?rel=0" allowfullscreen="" frameborder="0" height="480" width="853"></iframe>
Turns out the "cough and die" when you whack the throttle open from idle was a vacuum leak from the gasket between the head and the boot. Found a product called Permatex Permashield that's suitable for dressing intake gaskets that really worked wonders. Instant (hour) fix. Time will tell if it lasts. No more "cough and die". The accelerator pump seems to be doing its job but is leaking just a tiny bit for whatever darned reason. Still have a little bit of a hang/run-on idle and the spontaneous die from low idle. If I keep the idle a little higher, it runs fine. Rides fine, too. I think this is a fuel screw adjustment issue. A 30 minute ride around to cure the exhaust paint yielded what appears to be a lean looking plug, so that may also be a bit of an issue as well. I'm thinking I may raise the needle one clip position and see how things behave.
hi there i have the exact same issue. how did you pin point the leak? I've sprayed just about anything aerosol on the manifolds but no change in rpm. idles fine and keeps rpm fine if I don't roll on the throttle gently. turning in the pilot screw slows the rpm and makes the rpms hang and rise when throttle is kept constant. so I think I've found the right setting at about 2-3.5 turns out
even after a thorough warmup the hesitation persists. It is only an issue in slow turns and launches from stop though.