CB500 Clutch Rattle

Was hoping someone could tell me how to reduce/stop an annoying noise on my CB500 of what i believe to be clutch rattle.

Clutch out, moving along, and its rattling (most noticeable at 40mph in 2nd gear). Pull lever in, rattling mysteriously stops. And i hear that clutch rattle on the CB500 is common, so i've jumped to the logical conclusion (that its clutch rattle). Could be wrong, as i'm very much a newbie.

After a quick google, i've read carb balancing may help, so i plan to give that a go (well, pay someone i know to do it, as i'm not at the stage where i think playing with carbs is a good idea). Any other suggestions? Am planning to have valve clearance done too, as the bike is old with no service history.

And out of interest, what causes "clutch rattle"?

Not sure how balancing the carbs will help stop the clutch rattling but if it's an old bike with no service history it's worth doing anyway!

Unless we can see/hear the problem it's hard to diagnose it properly but it could be the clutch but could also be the cam chain tensioner (mine was running a bit loose a few weeks ago and after readjusting it's fine with no rattle anymore). Saying that the cam chain tensioner makes more of a fast ticking noise than a rattle.

With my limited knowledge of clutches I can only say what causes clutch rattle on Ducatis (they use a dry clutch where no oil is present whereas most other bikes use a wet clutch which is covered in oil). In a clutch there are several 'plates' called clutch plates (!!) and they have friction patches on them that engage/disengage when you move the clutch lever on the handlebar. When you look at the plates they're round with a hole in the middle and large 'teeth' round the outside that lock into the basket (what the plates sit inside) and when the clutch is getting old or worn down the teeth can become worn away around the edges which can cause some movement hence the rattle. As the friction material wears down there is also movement between the individual plates which also adds to the rattle. You only really notice it a lot on Ducatis because there is no oil to deaden the sound of it. Incidentally have you checked you oil levels? I guess if your oil is low that could affect it.

Sorry i couldn't be more direct with an answer! Perhaps someone else can have a go (and correct me if I'm wrong with any of my attempt).

Was hoping someone could tell me how to reduce/stop an annoying noise on my CB500 of what i believe to be clutch rattle.

And out of interest, what causes "clutch rattle"?

there are a number of things this could be on an old honda....

carb ballance (as you said)

cam chain tension

drive chain tension or wear

low oil level

rear cush drive worn

and of course, a knackered clutch or gearbox

apart from the last one, there is nothing expensive or difficult to check. you'd need a haynes manual if you fancy a stab at it yourself otherwise, just ask the mechanic to check these items specifically when you book it in for a service.

the noise comes from components in the drive mechanism bumping into each other when there is little or no load on the engine. think of riding a push bike but pedling slower than you need to to drive the bike foward. then pedling harder, you'll hear a clonck as the gears engage and you start to drive the bike with the pedals again.

it's made worse on old bikes because various items in the drive mechanism wear so the extra movement exagerates this problem.

Cheers for the informative answers guys.

It's not annoying enough for me to throw the cash to get all that looked over, but i think i can safely rule out oil levels and drive chain tension / wear because it's recently had an oil and filter change, along with a shiny new chain and sprockets. And otherwise i believe the gearbox is fine - it's alot better than the CG125 gearbox i had to put up with for a year, anyway!

I've got the Haynes manual though - so here's waiting for a warm day on which i can be bothered to take a gander (that is, when i get the damn thing back - it's been in the garage awaiting parts from the crappiest / most dishonest dealer in creation for the last week or so!)