I just picked up a 1987 XL600 which is in nice original condition. It runs great, but when I blip the throttle the RPMs will "hang" a bit, sometimes more than others. For example, if at idle I rev it a bit, it may stick at say 2000 RPM until I blip it again. Sometimes it will hang higher than that, sometimes not. I took off the seat, tank, and airbox today to check the obvious stuff: the throttle linkage is fine and does not bind, both carb slides are free and drop back closed when the throttle is released, and there no air leaks. The throttle cable adjustment looks good with a little slack as expected. Anyone experience this? Any help would be appreciated.