Knocking / rattling inside primary drive case + backfire

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marshg246 said:
One problem is that, as best i can tell, the Atlas and Commando have different threads.
Click to expand...

Yes, but the thread wasn't the problem. It replaced the original clutch nut but was over-length and clashed with the diaphragm spring centre.

Found on the old RGM website and in an old paper copy.

"040373M, CLUTCH LOCATION NUT, FITTED WITH SMALL GARTER SEAL FOR CLUTCH PUSHROD, C, "
"C" = Commando.
Knocking / rattling inside primary drive case + backfire


Edit:
marshg246 said:
The owner of the 750 told me the gearbox was from and Alas so I didn't look any deeper. The 72's clutch nut would not screw onto me 850 which also implies different threads.
Click to expand...

All Commando mainshafts and clutch centre nuts are the same parts and the Commando clutch doesn't fit the Dominator/Atlas mainshaft.

andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
 
Last edited:
L.A.B. said:
Yes, but the thread wasn't the problem. It replaced the original clutch nut but was over-length and clashed with the diaphragm spring centre.

Found on the old RGM website and in an old paper copy.

"040373M, CLUTCH LOCATION NUT, FITTED WITH SMALL GARTER SEAL FOR CLUTCH PUSHROD, C, "
"C" = Commando.
Knocking / rattling inside primary drive case + backfire


Edit:


All Commando mainshafts and clutch centre nuts are the same parts and the Commando clutch doesn't fit the Dominator/Atlas mainshaft.

andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
Click to expand...
Ok, that only leaves that the threads were recut the bike I was working on since the cNw parts fit my 74 but not the 72. And the 72 parts would not fit the 74. What he told me never sounded right.

The DynoDave and the cNw parts are only about 2-3 threads deep - WAY narrower that the picture of the RGM version.
 
marshg246 said:
The DynoDave and the cNw parts are only about 2-3 threads deep - WAY narrower that the picture of the RGM version.
Click to expand...

Yes because the Dynodave seal is an additional item and doesn't replace the nut but it (or the nut) could still need thinning down and that was what I had to do.
"3. You may reduce the depth of the clutch seal down to .120” by grinding or filing.
Typically .140” is actually exactly two threads of engagement.

4. Last, you can grind down the thickness of the clutch center nut 060895 (04373) which is .375/.383” thick. Thinner than .350" would not be typical."
 
There is a different dynodave clutch rod seal for Dominators.
I've used his Commando type seal on the MK3 and on the 920, which uses a 71 750 box.
They fitted fine.
I installed his Dommie type seal on the 650SS. That also went on without a problem.

Glen
 
L.A.B. said:
Yes because the Dynodave seal is an additional item and doesn't replace the nut but it (or the nut) could still need thinning down and that was what I had to do.
"3. You may reduce the depth of the clutch seal down to .120” by grinding or filing.
Typically .140” is actually exactly two threads of engagement.

4. Last, you can grind down the thickness of the clutch center nut 060895 (04373) which is .375/.383” thick. Thinner than .350" would not be typical."
Click to expand...
Ya, I've read/done that with both. No offense to the creators, but something more in line with a valve seal would make more sense to me. Since I use the later tab washer and thin washer there is very little thread for these.

FYI to those about to tell me to use Locktite and no tab washer - I'm not listening so you're wasting your time telling me! Triumph people love tab washers, Norton people hate them - don't know why, don't care why.
 
worntorn said:
There is a different dynodave clutch rod seal for Dominators.
I've used his Commando type seal on the MK3 and on the 920, which uses a 71 750 box.
They fitted fine.
I installed his Dommie type seal on the 650SS. That also went on without a problem.

Glen
Click to expand...
Is it a thread difference? Will a Dommie gearbox work on a Commando or will a Dommie mainshaft work in a Commando gearbox?
 
marshg246 said:
Is it a thread difference?
Click to expand...
The nut and therefore the thread go back to the early Dominator and continued to the 850 Mk3.
andover-norton.co.uk

Andover Norton Parts Drawings - Andover Norton Factory Parts - Commando Parts

Andover Norton Parts are the only Norton spare parts in the market manufactured to original drawings, within the factory-approved tolerances, from the correct materials, and with the correct finish.
andover-norton.co.uk
'1A'
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk

andover-norton.co.uk

Andover Norton Parts Drawings - Andover Norton Factory Parts - Commando Parts

Andover Norton Parts are the only Norton spare parts in the market manufactured to original drawings, within the factory-approved tolerances, from the correct materials, and with the correct finish.
andover-norton.co.uk
'18'.


marshg246 said:
Will a Dommie gearbox work on a Commando
Click to expand...
Yes, with the Commando mainshaft.
 
Looks like the Primary will be dealt with, then we can move onto the Backfire.....😁😁
 
I can't recall the differences between the two seal types only that the Commando type seal is not meant to work on the Dominator main shaft.

Glen
 
worntorn said:
I can't recall the differences between the two seal types only that the Commando type seal is not meant to work on the Dominator main shaft.

Glen
Click to expand...
Or vice versa. Dave's seals are definitely intended for use specific to Commando OR AMC type clutch.

Slick
 
L.A.B. said:
The nut and therefore the thread go back to the early Dominator and continued to the 850 Mk3.
Click to expand...
I'm convinced (already was) just confused about the problem I had. In my fasteners database I have 04.0373 as BSC (CEI) 5/8"x20 and I've added your note. Do you know if it is also right for Matchless and AJS?
 
B+Bogus said:
My RGM seal fitted fine after I skimmed about 1/8” off it; maybe more. As delivered it was unusable.
Click to expand...
Well that’s what I thought. But I put it on the shelf to do later and just used a standard nut. That was 10 years ago and I have never yet suffered from gearbox oil leaking into the clutch, even though I’m running a dry belt.

The OP might wanna think about that before he gets his knickers in a twist about all this …
 
Last edited:
FWIW….

This oil is designed for primary, gearbox, and wet clutches.

And it makes for a nice smooth shift... I use it as ‘standard’ in all my old bikes for the nice shifting qualities.

Use it in your gearbox and your primary and you never have to worry about one contaminating the other again!

www.hogparts.co.uk

Sport Transmission Fluid. 1 Litre

DescriptionBel-Ray, Sport transmission fluid. 1 litreDetailsSport Transmission Fluid has been developed for the unique demands of XL Sportster transmissions equipped with wet clutches. Bel-Ray Sports Transmission Fluid flows freely for better clutch cooling and provides positive clutch...
www.hogparts.co.uk www.hogparts.co.uk
 
marshg246 said:
I'm convinced (already was) just confused about the problem I had. In my fasteners database I have 04.0373 as BSC (CEI) 5/8"x20 and I've added your note. Do you know if it is also right for Matchless and AJS?
Click to expand...
It's the same nut as used on Dominators and G15/P11.

- Knut
 
marshg246 said:
In my fasteners database I have 04.0373 as BSC (CEI) 5/8"x20...
Click to expand...

However, CEI would be obsolete by this time and the 20 TPI series was discontinued after CEI had been adopted into British Standard, (CEI becoming British Standard Cycle thread in 1938), therefore, 5/8" x 20, also 9/16" x 20 at the other end of the mainshaft, also the nuts could in fact be 55° special Whitworth (Whit Form) and not 60° Cycle thread.
www.accessnorton.com

BSW/UNC Caution

We (especially those in the US) tend to call all British threads Whitworth. In truth not much BSW (British Standard Whitworth) is used in British motorcycles. BSC (British Standard Cycle)/CEI (Cycle Engineers Institute) are much more common (26 tpi). Then there's the BSF (British Standard Fine)...
www.accessnorton.com www.accessnorton.com
 
Hi all. Any tips for getting the circlip on to the clutch shaft? I’ve reduced the size of the upgraded circlip, but can’t see how to get it on without a big twist. I also have an original spec circlip, that one has a wider mouth and is thinner.
 
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