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Discussion Starter · #1 ·
So I started the bike today after 2 months or so (last ride was problem free, as always), and a strange beating noise is coming from the clutch. It's like the dry clutch sound but I can hear it even when riding the bike, the faster I rev, the faster it beats. I was afraid it's from the engine, but when I squeeze the clutch lever it goes away.

After several km's, I went back to the garage to see what's goin on. I took the clutch apart but everything seems to be ok, plates, springs, pushrod straight, not stuck on pressure plate, o-rings, pressure plate and bearing, slave cylinder works, gearbox too...

Please let it be something minor guys, I only neglected her because I'm renovating! :D
 

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Mr Leakered
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I agree that I never hear my clutch once it is under load. It will rattle at a neutral throttle, but definitely not constant.

Sometimes when I'm really lucky, the plates will bind up a bit (definitely not from moisture) on shutdown so the next morning I'll get no rattle for a few seconds on start-up.

Constant rattling under load is mystifying, esp if you checked out those bits. Is the basket tight?

Have a good one.
 

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Discussion Starter · #3 · (Edited)
Thanks tonered, I'll check that nut/bolts first thing in the morning, it may be it, actually is the only left plausible clutch cause.
I gave it another spin, same thing. The beating is loud and I can feel the vibration thru the frame. No more riding, that's for sure...
 

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This might be a little inconvenient, but do you have access to a dyno? With the dyno , you can be running it under load while off the bike and looking at the exposed clutch basket or going around the bike seeing if the noise is coming from one side or the other.

Ray
 

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Life is too short to worry !
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Could be the alternator flywheel coming loose , I believe that can be an issue on some bikes.

If you put it on the cente-stand with the engine running and use the fast idle to set the revs high you should be able to use a rod to move about the engine and locate more accurately where the sound is coming from.
(Are you aware of this diagnostic technique ?)
 

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Another, less encouraging thought, is it's something in the gearbox. When you pull in the clutch, you're disengaging the gearbox as the clutch hub is no longer tied to engine power delivered though the basket. You may try to put the bike on a rear stand and roll the tire by hand. May be best to do this in gear so the gears and shafts are working, so remove the clutch pack to allow free rotation.. Listen and feel for weirdness. It may even be helpful to remove the chain and move the countershaft sprocket by hand for a better feel. Bad news is if it's in the gearbox, you'll need to split the cases.

Might also drop the oil and check the sump screen and drain plug magnet for clues...
 

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I think he means to listen with a mechanic's stethoscope like tool. Just using a rod will transmit sounds from where the end of the rod is touching through the rod that you can hear. Best to use something made of a resonant material. Aluminum maybe?
 

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Discussion Starter · #9 · (Edited)
Guys, thanks a lot for your responses!

Geabox, I'm aware of the technique, I used a hammer-through screwdriver, but the noise is covered by the basket and the exhaust, so I can't say for sure... Don't think it's the alternator nut either, the noise stops as I pull the clutch lever, but I'll check that too.

SS904, the gearbox is what I suspect also:
- took out the pressure plate and plates, started up, no bad sound. The basket has a little play but I find it normal, the hub a little more play, but again, I think is OK, someone correct me here. I couldn't take the damn nut off, I'll have to try that again with a pneumatic gun or something.
- clutch back on, start-up, there's the noise, the normal dry clutch noise but present on any engine rev.
- I ride it around the block, gears 1-3, sounds a lot harder, like the intake when riding with an open airbox, but coming from, I think, the gearbox.

Doing this after sitting for several months I'm thinking of a bad bearing also...
Well, I'll start with that clutch nut and see were it gets me and post here with the results.
Thanks again!
 

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Discussion Starter · #10 ·
So, I started working on her a month ago, sadly, I'm free only on Saturdays...

At this point eveything seems very OK with the engine... pistons, cylinders, gudgeon pins, crankshaft, any bearing I could check, etc. I only found 2 valve shims out of specs.

Anyway, at this point I would be very hesitant to open the cases if it wasn't for that damn galley plug.

I have a couple of questions though:
- do I need a puller for the crankshaft timing gear, it comes off by hand about 5mm then it stops, and
- what are the small scratches on the inside of the cases, where the cylinders sit?
 

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Oke, i know i'm a newby and stuff...
but i had a very similar experience with my formerbike...
the location of the problem was hard to find, also got acquinted with the stick method and stuff.. but nothing clear (which i should hae seen as a sign)

the deal was that the problem was the bearings off the rear wheel, but while on the bike it came from the clutch region, also why the stick didn't work.
if someone told me at that time it was the rear wheel (bearings) i would've send them to the nut house...

also part of the problem,.. at thebeginning the sound only happend whe the chain pulled on the wheel when clutch on. with clutch of it was as silent as a bird...

hope for you that that is it, cause it's an easy thing to fix (way in you capability as i so see) and not costly (which you'll probably know)

best of luck there...
 

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Discussion Starter · #12 ·
Thanks Spikey, the wheel bearings are fine... unfortunately!
For the record, the crank timing gear is blocked with a wooduff key that one should push a little and the gear slides off by hand!
 
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