20 miles with banging valves

[Harold_Shand]

Mmm. Valve clearance neglected, now have to ride 20 miles to garage with bike knocking.

what's the consensus? Ride it or get it towed?
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Harold_Shand's theory might be the best explanation.

[hmmmnz]

knocking??
that doesnt sound like valve clearance to me,
have you checked the tensioner is working properly??

knocking always makes me think big end.... its not a honda is it??
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[Harold_Shand]

'04 kawasaki ZR7, 19k

valves overdue by 2k. Knocking that increases with acceleration and backfire with harder accelaration.

Plug gaps ok

cct been a worry since i first got it... rattling when slowing down, but it's been doing that on occasion for 11,000 miles.
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BCF's 6th favourite poster 2009-2010

Harold_Shand's theory might be the best explanation.

[Harold_Shand]

...so it would seem the cam chain may have missed a tooth and fucked the valves up...



Oh. Fuck bikes.
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BCF's 6th favourite poster 2009-2010

Harold_Shand's theory might be the best explanation.

[ms51ves3]

[iooi]

If its got shims then they get quieter over time. Due to the gap closing up.
Sounds more like cam chain is slack. Or you have a serious lack of oil.

I would not think that riding 20 miles is going to make any difference. So long as you not redlining all the way.
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[Barry_M2]

[stinkwheel]

[Barry_M2]

Stink, I mean if the valves were banging against the pistons / bent, which is what he seemed to think in the post above mine (which I quoted).
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[alun111]

[Kickstart]

Hi

Seems they are shimmed valves on the ZR7. As iooi says these normally get quieter as they wear as the clearances tend to tighten up.

I would also not expect it to make a significient difference to the clearances if you are just a couple of thousand miles late adjusting them.

If the cam chain jumped a tooth then the bike might well still run (had a car where a cam belt had been changed and put 1 tooth out). However if it jumped enough for valves and pistons to touch then I doubt it would run.

One possibility would be that it has managed to spit a shim out resulting in one of the clearances being massive. In which case don't even run it (lots of things the hardened shim could get caught in and cause serious damage).

All the best

Keith
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[Harold_Shand]

It's running as sweet as a nut, just this knocking and farting when accelarating. I've got a week off next week. The last oil change under 100 miles ago I used cheap oil, coincidence?

There's plenty of oil in as it stands. HT leads all fine... what about wd40 inside the ht caps? i just think this will be something simple because the bike is running A1 otherwise.
____________________
BCF's 6th favourite poster 2009-2010

Harold_Shand's theory might be the best explanation.

[hmmmnz]

i think its cam chain slap from a dodgy tensionor,
take the tensioner out and check the spring ect,
then put it back in and see if you can hear it click when it retensions itself,
turn the bike over by hand,
then loosen the bolts on the tensioner slightly untill you hear another click, then tightebn it back upagain,
then start and see if thats made a difference,
i would be taking the rocker cover off as well and see if everything is ok in there and that the shim hasnt popped out,
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