www.zxrworld.co.uk

OK chaps, I need your expertise on a couple of problems I have.

First off, the engine is running fine but is displaying some odd behaviour. When I rev the engine even a tiny bit, the revs will rise to about 2,000rpm and hang there for about 5 seconds before dropping back down to idle. The hotter the engine is, the longer the time until the revs drop to idle, unless I've had the throttle held constant a while (ie on a motorway) where they will sit at 2,000 indefinitely. They will drop back down to idle if I load the engine slightly (stick it in gear and let out the clutch a bit) but will sometimes shoot back up to 2,000 on their own. I've checked all the basics (throttle cables, idle setting, carb slides etc) which all seem to be OK. Any other ideas as to what could be causing it and possible solutions? I've read around a bit and my best guess is air might be getting in the system somewhere it's not meant to, inlet rubbers perhaps? I'll double check everything just to be sure, but I'm a complete novice where carbs are concerned so please be gentle with me

I can make a quick video of this and YouTube it if my description makes no sense.

Second, I have a very minor oil leak. It doesn't leak when standing and I suspect it's the rocker cover gasket weeping. I'm gunna give the engine a thorough clean later to confirm this, but assuming I'm right what's the best way to stop it? Some kind of sealant maybe? Cleaning the couple of splats off my boot after every ride is getting a bit tiring.

Any help with these problems would be much appreciated, I'd like to start learning how to do these things myself rather than pay someone else to do them

Some ZXR's do that with the revving, not sure why tho. Have a look at the air box, theres meant to be bungs in the top where you remove two bolts to take the airbox off, they get lost usually and will introduce some unfiltered air into the box.

As for the leak find out where its coming from, either a new gasket if its not too major or some hermatite sealer if your stingy. Also check that the expansion bottle isnt leaking cos ive ad that where i thought it was oil which tunred out to be coolant because the cap wasnt screwed on properly!

i didnt bother to read all of that,but basically the rev thing is becuase its too lean. eg. too much air in the charge, compared to amount of fuel. if you find a leak, it may well cure this problem.

I had exactly the same problem. I'm told that over the years the diaphrams had become very worn and if they are not right where they should be then you get alsorts of problems. Anyway got doner carbs from ams. mad e a reasonable set out of the two and now it doesnlt happen.

revs hanging at 2-2.5 k is either a slightly lean mixture, or worn slides in the carbs, it only takes one to stick slightly and hang a fraction of a mill open to do this.