rev problem is driving me insane

[Guest]

i have a gsxr 600 srad 1998, when i twist the throttle it gets stuck at 3000rpm and slowly drops to normal idle. sometimes it stays at 3000 until i mess with the idle knob by the coolant bottle.. this is what i've done so far, i've checked for a vacuum leak (none). i changed the carbs and done a carb sync, i changed the stator and i changed the rectifier none of which have helped. sometimes it will be ok and then when i pull up at a junction the revs just go up like they have a mind of there own. i need some help with this, its driving me mad. someone said an unseated valve could cause this problem, dont know if thats true, but would like to exaust all avenues before i take the head of and check that. thanks. all ideas welcome.

[Stu]

you checked all your throttle cables to make sure they aren't sticking?

[eastanglianbiker]

also check for air leaks on the inlet rubbers

[stevie16v]

As above, it sounds as thought some air is getting in to it, that'd be the first place i'd start looking

[Guest Hodgy]

Sticky cables or linkage on carbs would be my starting point

[Guest]

i removed the head and noticed one of the valves wasn't sitting right, cleaned and lapped, now bike runs spot on, thought i'd post my answer incase someone has the same sort of problem.

[Tango]

i removed the head and noticed one of the valves wasn't sitting right, cleaned and lapped, now bike runs spot on, thought i'd post my answer incase someone has the same sort of problem.

Strange symptoms....but glad you got it sorted mate and thanks for taking the time to post up what you found, could well help someone else in the future....

[megawatt]

Well, never heard that before! How can lapping a valve in help the engine stop revving with the throttle shut??? Think you have put it back together and disturbed what was causing the problem