Honda Hornet CB600 - Rattle

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Thu 11 Nov 2010 16:39
Honda Hornet CB600 - Rattle - Cris_on_the_gas

Trying to identify a rattle. It is worse when riding and shutting down throttle, noise seems to go away when under acceleration. Chain has always been lubricated and has got about 1 1/2 " of play , no real tight spots on chain. Chain & sprockets were replaced about 2years ( 8000 miles ago). Don't think chain is worn as can't pull off rear sprocket. Seems to make a slight groaning noise when pushed around the garage, have got another bike and this does not make same noise.

Tried putting it on paddock stand and get sort of groaning noise when rear wheel rotated same as when pushing it. Checked rear sprocket and looks OK, no shark fins shapes as I have been told this is sign of wear.

Any suggestions what to check appreciated

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Fri 12 Nov 2010 14:05
Honda Hornet CB600 - Rattle - SteveLee
You say the chain has been lubed - but how often? (I give mine a quick spray after every ride.) If the chain has been allowed to dry out - even once, the o-rings will quickly fail, water will enter the affected link(s) and it will quickly knacker itself.

If the groaning (and resistance to rotation) is constant, your rear wheel bearing has probably failed, on the paddock stand, grab the top and bottom of the wheel and try to rock the wheel - any movement and it's history. If the chain has been run too tight at any point the bearing can be killed in a matter of days as can the gearbox sprocket bearing (engine out to fix) easiest way to tell would be to remove the rear wheel and check the bearings by hand. I hope it's not the gearbox sprocket bearing from an overtight chain (Kawasakis are usually the worst culprit for these.) as this will be rather expensive to fix.

Wheel bearings can be replaced by any half-competent DIYer with a basic toolkit.
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Fri 12 Nov 2010 14:12
Honda Hornet CB600 - Rattle - SteveLee

PS wheel bearing life varies drastically, anything from 4K miles to 30K+. If the rider insists on using a pressure washer to clean his stead then wheel bearings can become regular consumables!

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Fri 12 Nov 2010 14:15
Honda Hornet CB600 - Rattle - SteveLee

PPS could also be rear pads worn or caliper sticking, try to ease the pads back into the caliper with a screwdriver and then see if the wheel spins freely.

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Sat 13 Nov 2010 17:35
Honda Hornet CB600 - Rattle - Cris_on_the_gas

Thanks for the advice Steve, just had time to check out bike. No play in rear wheel bearings at all and the chain has always beencorrectly lubricated since fitiing. got the bike on paddock stand and ran at tick over in first gear. The rattle seemed to come for the front sprocket area so took off cover and there is some play on the spline where the front sprocket connects the the drive shaft. Not sure drive shaft is the right word but this rotates with the engine and drives the chain. The noise is coming from this area. Not sure if the its the sprocket that worn or the shaft. I have ordered a new sprocket and chain set as will need one anyway, but if the spline is worn can these be replaced easily ?

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Sat 13 Nov 2010 20:45
Honda Hornet CB600 - Rattle - SteveLee
It might just be a loose front sprocket nut, apply a tightening force whilst applying the rear brake. The sprockets should have been replaced as a pair - if not wear on the chain and sprockets will be accelerated, of course the oldest "front" sprocket would cry foul first.

If the output shaft splines are worn or damaged - flog the bike quick before it gets any worse. The engine needs to be removed and gearbox stripped down to replace it ditto for the bearing on the output shaft.
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Wed 17 Nov 2010 10:07
Honda Hornet CB600 - Rattle - Cris_on_the_gas

Changed chain & sprockets and the new front sprocket is a much better fit and there is no play on the splines anymore. Just noticed that it is possible to move the front sprocket in & out a bit even although the front sprocket nut is torqued up correctly and the washer is in place. don't know if this is normal or not.

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Wed 17 Nov 2010 14:56
Honda Hornet CB600 - Rattle - SteveLee
Some sideways play on the front sprocket isn't a concern as long as the sprocket nut is secured properly. I wonder if the wrong sprocket was fitted in the first place? Anyhow nice to hear it's sorted, a regularly lubed chain and sprockets should last 20K+ on a four cylinder bike. I got 25K out of my last set (Hayabusa) including doing some drag racing and track days.

Edited by SteveLee on 17/11/2010 at 14:57

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