idle is going crazy?

I've done a few jobs on the ZZR11 of late, replaced airfilter, plugs, etc. And I think I may have upset some hose or something? When sitting on the stand, engine running and fully warmed up. "no throttle inputs" the engine will vary in RPM by up to 1000. Racing up and coming back down again all of its own accord? MADNESS

I'll pull the airbox off again and have a look around but if anyone has had a similar experience and knows the obvious reason, then by all means say away. I don't know if it's relevent but I have adjusted the idle quite a bit trying to get it right, tweeking the remote knob down under the LH side of the tank. Perhaps one of the carbs didn't follow the rest during this process? Fark Knows.

check for an air leak. easy check is to spray wd40 / aerostart around the carby body/away from the air intake, if revs rise higher, voila, air leak.

Definitely sounds like an air leak (just in-case you wanted a second opinion).

let me guess.....u took the tank off to do this work???


take it off again..id suggest looking for a pinched hose..maybe air line, or a fuel line....fuel tank breather isnt obstructed??

fuel line is clear & fuel is getting to carbs ok??

other than that..im outta ideas....good luck with it tho...

well I sussed the clamps on the rubber intake manifolds and the screws were pretty loose. My mate Stevo and I tweaked them up 4 or 5 turns, sprayed a little lube on the carbs connecting rod and put it all back together. Idles fine now, all the way up till the fan engaged and for 5 minutes after. Just hovering around 1000/1050.

"Air leaks for sure then"

thanks for all the input.

if its hovering at idle i would be investigating a carby balance, are your valve shims due for a check get them done first if they are and a carby balance and it should run like a million bucks.

It would be due for both shims and a balance I recon bob. When I do that I want to put that jet kit in that takes care of the off-idle abruptness issue. At least for now it's running relatively smoothly again.