Commando Gearbox / transmission noise

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Nortoncommandoneil

Joined
Jun 9, 2004
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My 850 Commando has what appears to be a whine and the odd clunk mainly in second and third gear.
While slow riding in second gear and slightly opening and closing the throttle it's very noticeable and rough. I've placed the bike on the centre stand and ran it in second gear with the wheel off the road and its not so noticeable.

Originally I wondered if it was the engine but it's difficult to conclude whats the issue.

Any advice would be appreciated.

Also if it's gearbox related is it difficult to fix.
Are there any tests i can do to confirm what area the problem is.
 
Predictions, predictions based on a whine. The list would be long, gear surfaces spalling, shafts bent, shafts worn, gears worn, bearings on way out etc etc.

You best just open it up, if you do not have confirmation from a Previous owner or from having it done yourself you would be advised to look at and replace the inner layshaft bearing if its a ball bearing with a metal cage. Replace with roller bearing or the special plastic caged ball bearing. While you are in there you can check the gears, shafts, bearings and bushes.
 
kommando said:
Predictions, predictions based on a whine. The list would be long, gear surfaces spalling, shafts bent, shafts worn, gears worn, bearings on way out etc etc.

You best just open it up, if you do not have confirmation from a Previous owner or from having it done yourself you would be advised to look at and replace the inner layshaft bearing if its a ball bearing with a metal cage. Replace with roller bearing or the special plastic caged ball bearing. While you are in there you can check the gears, shafts, bearings and bushes.
Click to expand...
Would this be something I could do myself ?
I've heard mick Hemmings video is good.
It's different to find people that will take these jobs on even if you're a club member, which i am.
 
Last edited:
Nortoncommandoneil said:
My 850 Commando has what appears to be a whine and the odd clunk mainly in second and third gear.
While slow riding in second gear and slightly opening and closing the throttle it's very noticeable and rough. I've placed the bike on the centre stand and ran it in second gear with the wheel off the road and its not so noticeable.

Originally I wondered if it was the engine but it's difficult to conclude whats the issue.

Any advice would be appreciated.

Also if it's gearbox related is it difficult to fix.
Are there any tests i can do to confirm what area the problem is.
Click to expand...
Is this a new problem or one you've always had?

Put on center stand with rear wheel off the ground. Pull the clutch and tie it pulled. Turn the rear wheel while changing gears. If you hear/feel it, it's not the engine. If you don't hear/feel it, you've learned nothing.

The only hard part of gearboxes is getting them to shift properly. Don't mess with the components in the outer cover and that won't change. However, to do anything meaningful in the gearbox, you need to take the primary apart which is not hard if you have the proper tools. With the primary disassembled and the front sprocket off, you can get the gearbox apart to inspect.

BTW, "clunks" going into gears is normal. If you mean clunks while in gear, you need to find and fix it.
 
I had never done much motorcycle work before i had the Commando and i was able the do the gearbox rebuild myself with box still in bike frame. I followed Hemmings video, read a bunch of how to articles and of course got lots of guidance on this forum. I bought the overhall kit of parts from Andover but opted for the alHemmings recommended phenolic cage deep ball bearing for layshaft.
 
marshg246 said:
Is this a new problem or one you've always had?

Put on center stand with rear wheel off the ground. Pull the clutch and tie it pulled. Turn the rear wheel while changing gears. If you hear/feel it, it's not the engine. If you don't hear/feel it, you've learned nothing.

The only hard part of gearboxes is getting them to shift properly. Don't mess with the components in the outer cover and that won't change. However, to do anything meaningful in the gearbox, you need to take the primary apart which is not hard if you have the proper tools. With the primary disassembled and the front sprocket off, you can get the gearbox apart to inspect.

BTW, "clunks" going into gears is normal. If you mean clunks while in gear, you need to find and fix it.
Click to expand...
It's always been noisy but its definitely worse than it was.
The clunking is when selecting second gear and opening the throttle slightly.
 
I had a whine too. My primary chain was too tight, and the resulting pressure wore on the sleeve gear bushings. New bushings from A/N and correct chain adjustment fixed it. The A/N bushings fit great with no reaming.
 
Nortoncommandoneil said:
It's always been noisy but its definitely worse than it was.
The clunking is when selecting second gear and opening the throttle slightly.
Click to expand...
Still not sure.

There should be a clunk regardless of throttle. If you put it in gear, wait a couple of seconds and then give it throttle does it clunk? If so, try being more forceful putting it in gear and see if that goes away. Sometimes, the selectors move the gears 99% into place and then they clunk into place - I usually see this with people who have modern bikes and are used to easing them into gear - you must "meant it" when putting a Norton gearbox in gear. The other possibility if that is that case is that the shift mechanism is not working perfectly (weak/worn/bad "hair spring").

As @1973x75 said, a too tight primary chain can cause a whine, and the rear chain being too tight can as well. They both put too much pressure on the sleeve gear bushing.
 
I be checking the primary chain first could be a loose chain or tight chain but it be the first place to go, the chain could have tight spots as well loose everywhere else, could also be chain slap from slow to opening the throttle, drain the oil and pull the cover off, part of general maintenance, how long have you owned your Norton, noises can travel so finding where it's coming from is like finding a needle in a hay stack.

Ashley
 
kommando said:
Predictions, predictions based on a whine. The list would be long, gear surfaces spalling, shafts bent, shafts worn, gears worn, bearings on way out etc etc.

You best just open it up, if you do not have confirmation from a Previous owner or from having it done yourself you would be advised to look at and replace the inner layshaft bearing if its a ball bearing with a metal cage. Replace with roller bearing or the special plastic caged ball bearing. While you are in there you can check the gears, shafts, bearings and bushes.
Click to expand...
Around 2010, I bought a new and complete gear cluster for a Norton gearbox for less than 800 Australian dollars. A crack in the housing might not be easy to fix.
 
When I built my bike, I took everything apart and inspected - I also gave it all new bearings, and chains. The reason for owning a Commando or Harley is they are completely rebuildable.
 
Maybe rear wheel cush drive rubbers knackered. Sleeve gear bushes moved and wearing away. Whats the history with this bike? Are you new to it? Whereabouts in the UK are you?
 
acotrel said:
When I built my bike, I took everything apart and inspected - I also gave it all new bearings, and chains. The reason for owning a Commando or Harley is they are completely rebuildable.
Click to expand...
Which Harley have you owned?
 
Nortoncommandoneil said:
Would this be something I could do myself ?
I've heard mick Hemmings video is good.
It's different to find people that will take these jobs on even if you're a club member, which i am.
Click to expand...
The AMC box is really very simple, and Mick's DVD is very good, as is his engine DVD.
Buy the DVD, get a workshop manual and the necessary tools and dig into it, it's really not hard.
There is also the Old Brits article, which I think is in the files section of this website?
 

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