Chain - how loose ?

[Inno]

Hello,

I have little knowledge of upkeep of my bike and at the moment there seems to be a noise coming from the back of the bike when changing gears....

The chain seems loose as I can puch it to up in the middle so it hits the frame.

Would this be causing the noise when changing gears and driving at certain speeds ?????

Bike: CBR 600 F (99) 20k miles

[fazed]

Could well be specially when changing down or if you have clunky gear changes , I always have about a inch of play at the tightest spot on the chain , you should have a indicator on the swingarm also displaying how much life the chain has left

[Git]

Sounds very possible that the chain is the cause of your noises.

I would, first
raise back wheel off floor, clean chain and lube.
tension till I had 30mm of slack at tight spot.
tighten axle and lower back wheel.
sit on bike and re check tension from tight spot.
if you still have 30mm of slack
if not, you have over adjusted, do again

30mm was a general spec and nothing for definite on your bike, tension as per factorys book then tweak if needed.

if the chain is factory fitted and on 20,000miles it may be almost at the end of its life, check for worn sprockets, curved teeth and if it has stretched that much there wont be much adjustment left on swing arm adjusters.

i hope that was of some help on this wonderful sunny tuesday morning.

[Inno]

Thanks for that to you both, I will go sort it !

cheers

[billy whizz]

Might be a good idea to check out the Cush drive rubbers as well, they can make gear changes clunky and noisey when they wear out.
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[jonboy]

Standard chain slack for your bike is 25-35mm at the mid point mate, acording to my Haynes manual.

[TiN]

I find that the recommended 20mm+ of slack is too much (for my liking), so I usually go for just under that, maybe 15mm.
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TiN
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