Hanging revs and backlash

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Hey all, ive rebuilt my bike and im happy with it, except for the hanging revs and somewhat backlash of the camchain under 1300 rpm. The backlash, or so i think it is, is only under 1300 rpm...my newish dual plugs give me problems, but my old single electrodes are good, might get a new set of them. The hanging revs is at 2000 rpm and ive had that since day 1, no matter what i do with the mixture. Ive got 102 jets and screws at 2.5 out each. Im thinking of sending it to a good place to sort the carbs and maybe down jet if needed. Otherwise, starts first time from cold and warm, runs well

[RedexRobB]

The hanging revs sound like an air leak somewhere. Im guessing they hang when you either rev the bike or you come to a stop? The usual culprits are the O rings between the inlet rubbers and the block. You could also have loose clamps that hold the carbs onto the rubbers so check those first and see how you go. You can also check by spraying carb cleaner round the inlets and see if the revs change, if they do then your leak is round there somewhere.

Cam chain backlash? Not quite sure what you mean by that but your engine shouldnt be running under 1250rpm anyway as that is the reccomended idle speed. If you mean its making a noise, its quite common for them to be a bit noisy but obviously theres a point where its so noisy that something isnt right. Usual culprit for that is the tensioner needs resetting or the tensioner blade needs renewing.

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Thanks rob, i think its the tensioner aswell.. I got a new chain but not tensioner. New tensioner has already been ordered anyway. Its also probably inlet rubbers as u say, the gaskets were squashed. Also 1 of my pilot screws doesnt have a o-ring. Im going to go another half turn out as im running a bit lean. The backlash sounds like the chain is running on the metal and loose but its only below 1300, above that and the engine sounds good

[Robbie]

Is it not the clutch rattling? Try pulling in the clutch see if it goes away?If so its normal.

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Yeh it is clutch rattle..pulled in clutch and it went away. I tightened the cable so its much less and i also managed to get rid of most of the hanging..think it was the airbox to carbs, got a good seal. Good cold start aswell so im happy, thnx 4 the help

[cargo]

Yeh it is clutch rattle..pulled in clutch and it went away. I tightened the cable so its much less

I'd like to hope that you left enough slack on the clutch cable so that the clutch isn't lifted and therefore slipping. If it is even only doing this very slightly you will end up with a very worn clutch and it might be so slight that you dont notice.

Just the first thought that came to my head when I read your post

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Thats some good advice, ill put it right, thnx cargo

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The clutch was slipping when i was out

[kawasakisean]

all zxr400's suffer from clutch basket rattle once engine is well worn in its normal and gets worse when hot, nothing to worry about but a new clutch does cure it mines been rattling for 30,000 miles
bad iddling usuall air leaks or carbs need cleaning, try usung a bit of clean grease on all the seals when reassembling things

[azz2693]

all zxr400's suffer from clutch basket rattle once engine is well worn in its normal and gets worse when hot, nothing to worry about but a new clutch does cure it mines been rattling for 30,000 miles
bad iddling usuall air leaks or carbs need cleaning, try usung a bit of clean grease on all the seals when reassembling things

hi, i know this was a long time ago that you posted but i've just got my self a zxr 400 and i have noticed mine also has some backlash from the clutch, when you say replace the clutch do you mean the whole thing or just the friction plates and clutch plates?
cheers for you post, put my mind at rest its nothing serious but definetly would like to get it fixed in the near future if possible.
thanks