hello
ive recently been restoring my 1984 zx 750 gpz and i have a problem.
the motor revs up to 4500 rpms holds for a couple of seconds then comes back down to idle.
it does this when im at stop lights too .
this is very annoying and unsafe ...
anyone have any ideas as to why my bike is doing this on its own.
(no the throttle isnt sticking )
it has been doing this for 2 months now which keeps me from riding.
please give me some ideas.
robert

 

Hey Robert, first of all welcome to the forums. It could be rich with a vacuum leak. fire it up and use carb cleaner around the carb area and cyl. head. If it starts to slow its a vacuum leak. If it stalls its a bad leak.

Also check that the cable has slack and is properly routed.

 

(If it bangs the rev limiter, it used to be a drag bike.....)
Welcome to the forums, r.
Gear up; stay safe.

 

Welcome to KF and post up some pics of the bike.

as mentioned could be a vacuum leak at the carb boots because they are cracking from age. Could be that you need to adjust or lube the throttle cables, or redo a new grip install to allow proper throttle snap back.

 

thanks guys ill try all the suggestions today.
i have a can of carb cleaner, an extra set of carb boots , and ill rerun the throttle cable.ill follow up latter today.thanks guys robert

 

ok so i did as instructed.
i rerouted the throttle cable ,the twist is better but not the issue.
i sprayed carb cleaner around the carb boots and no it didnt bogg ..
yes it did accellerate to 4500rpm then came back down.sprayed three times same result...soooo new carb boots ?? is what im thinkin.

 

kinda sounds that way robert. either the carbs are not seated correctly or you can visually see cracks in boots normally.