Horrible noise from gearbox(?)

My comment has nothing to do with the noise, but if you currently have a friction plate against an alloy pressure plate in the RGM clutch, add that steel you took out so that it is against the pressure plate leaving the rest of the stack in the same order. Your clutch plates will last longer as will the alloy pressure plate. This tip is in the instructions that come with the RGM clutch. I did not make it up, or read it somewhere on the internet.

If you are using automatic transmission fluid in your gearbox, change it to a gearbox or differential oil.

Bearings, bushes, or shafts are the only things I am aware that will whine. Too much stress from the rear chain if it is too tight with your weight on the bike and a tight clutch belt could eventually cause problems. Sleeve gear bush could be hurting. Or the gearbox shell has shaft alignment problems which is why it was sold.

Guessing is fairly pointless even though that is what makes this website work.

When I get close to going bananas, I buy new parts. A new Commando gearbox is relatively inexpensive for keeping your sanity and would solve your problem more than likely.
 
Test, rather than guess..

Take the final drive chain OFF completely so you eliminate, chain rubbing noise, chain/sprocket noise, any sort of back wheel noise, etc. Run the bike through the gears on the center stand. Did the sound change? disappear? If it's still there, and the same, then maybe you've eliminated the final drive chain from the list of causes...
 
DennisMo said:
1) Does it make the noise if you put bike on centre stand in neutral with engine off and then rotate the rear wheel by hand?

2) Does it make the noise if you do the above, but with bike in a gear and clutch pulled.

Dennis
Click to expand...
1) I don´t have a centre stand, but I´m going to try and get the rear wheel up in the air and see (hear) what happens.
2) See above.
 
Schwany said:
My comment has nothing to do with the noise, but if you currently have a friction plate against an alloy pressure plate in the RGM clutch, add that steel you took out so that it is against the pressure plate leaving the rest of the stack in the same order. Your clutch plates will last longer as will the alloy pressure plate. This tip is in the instructions that come with the RGM clutch. I did not make it up, or read it somewhere on the internet.

If you are using automatic transmission fluid in your gearbox, change it to a gearbox or differential oil.

Bearings, bushes, or shafts are the only things I am aware that will whine. Too much stress from the rear chain if it is too tight with your weight on the bike and a tight clutch belt could eventually cause problems. Sleeve gear bush could be hurting. Or the gearbox shell has shaft alignment problems which is why it was sold.

Guessing is fairly pointless even though that is what makes this website work.

When I get close to going bananas, I buy new parts. A new Commando gearbox is relatively inexpensive for keeping your sanity and would solve your problem more than likely.
Click to expand...
Well we have different views on money, I definitely don´t think a new gearbox is "relatively inexpensive". But never mind, so, the steel plate I took out was in the bottom, there was two on top of each other and the stack was too thick. Should have been clear on that. Many Norton owners use ATF oil, which they are very happy with, so I can´t see why I shouldn´t try?
 
Since you imply the gearbox has been rebuilt, did the 3mm thick washer between the top mounting lug and frame mounting plate get installed? Quite common to see bikes missing this spacer washer. Leads to distortion/bending of framplate and then all manner of misalignments.
 
fiatfan said:
Now I really need help, soon going totally bananas..... Background is this: completely restored and somewhat upgraded 850 engine, works fine, no problems there. Primary is a new belt drive and dry clutch (complete) from RGM and a new stator. Gearbox have new bearings and bushings, new kick axle. Also a used shell in great condition, found that in the US. There are no rubber mounts, it´s solid bolted in the frame.
The problem is this: As soon as I start rolling, accelerating, there is a terrible grounding and whining from somewhere in the transmission, not a sound that I have to really listen closely to hear, it´s loud! And I also feel it in the bike. It´s fine when the engine is running, standing still, no sound when I pull/release the clutch, put it in gear still no noise, but when I start rolling it imediatly starts making that noise. When I drive and not accelerate, just let it roll and the throttle off, still in gear, the sound dissapears. It´s only when there´s a load on the transmission.
My guess is the box, but what can make such noise, I´m out of ideas. Have had the box apart twice this summer, find nothing wrong in there.
Ideas please, anything!?!
\Tommy
Click to expand...
I have just installed a belt drive in my cdo. I had such a noise in mine too. Turned out the clutch hub was rubbing against the primary inner cover round rib. I machined off .040 off of it and everything is fine now.
 
fiatfan said:
Well we have different views on money, I definitely don´t think a new gearbox is "relatively inexpensive". But never mind, so, the steel plate I took out was in the bottom, there was two on top of each other and the stack was too thick. Should have been clear on that. Many Norton owners use ATF oil, which they are very happy with, so I can´t see why I shouldn´t try?
Click to expand...

Yeah I probably do have a different view on throwing money away on a Norton. lol

I have an RGM belt clutch. Of those two steel rear plates the thick plate stays on the back and the thinner plate can be put where I suggested. The stack height with that thinner plate in front is not an issue on my RGM clutch. Unfortunate that RGM sent you a clutch with the wrong stack height.
 
Don't just think about it, something is not right so start digging into it to find out what is causing the problem, but get the rear wheel off the ground and start spinning it, out of gear, in gear and listen for anything rubbing, the problem with noise or rubbing when riding can sound like it come from one area but might be coming from elsewhere, start at the primary and look for signs of rubbing or wear marks, if none then get into that gear box, anywhere there is moving parts look for signs of anything not right.
You said you used shims to tighten things up, maybe too much, Nortons seem to like a bit of free play/end play in moving parts.
Don't ride the bike till this problem is sorted and if it's as loud as you say then something major will fail, retrace all the things you have done as something is not right.
Hope it's a simple fix for you but no matter how much time it takes, fix it.

Ashley
 
Tornado said:
Since you imply the gearbox has been rebuilt, did the 3mm thick washer between the top mounting lug and frame mounting plate get installed? Quite common to see bikes missing this spacer washer. Leads to distortion/bending of framplate and then all manner of misalignments.
Click to expand...
It´s in there where it should be.
 
Schwany said:
Yeah I probably do have a different view on throwing money away on a Norton. lol

I have an RGM belt clutch. Of those two steel rear plates the thick plate stays on the back and the thinner plate can be put where I suggested. The stack height with that thinner plate in front is not an issue on my RGM clutch. Unfortunate that RGM sent you a clutch with the wrong stack height.
Click to expand...
Well I´ve "thrown away" lots already, so.... An update on the gb oil, I was a bit tired and stressed yesterday, there´s no ATF in the box, I bought a Redline so that´s what´s in there. It´s blue, which I find slightly amusing....
 
frank73x89 said:
I have just installed a belt drive in my cdo. I had such a noise in mine too. Turned out the clutch hub was rubbing against the primary inner cover round rib. I machined off .040 off of it and everything is fine now.
Click to expand...
But the clutch housing turns as soon as the engine is running, so the noise should be there all the time? Or does something change when you put it in gear? I have the inner cover properly aligned, so it´s straight, but maybe I should remove the housing just to be sure.
 
fiatfan said:
Well I´ve "thrown away" lots already, so.... An update on the gb oil, I was a bit tired and stressed yesterday, there´s no ATF in the box, I bought a Redline so that´s what´s in there. It´s blue, which I find slightly amusing....
Click to expand...
FWIW, I had some bad results with Redline ShockProof gear lube. In my case it appeared as though the lube did not get between the bush and gear/shaft areas. Not saying it’s bad stuff, but it didn’t work for me.
 
If the Redline shockproof gear oil is used it must be stirred or mixed first. A thin blue layer sits on top and the solids sink to the bottom. It should look grayish not blue. The one I'm using is the lightweight version.
Russ
 

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