Mk3 gearbox: mainshaft circlip

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Ivodispili

Ivodispili

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I'm rebuilding my '77 MK3 gearbox and I have just noticed that the circlip on the mainshaft, behind the gearbox sprocket, is missing on the parts catalog (or, at least, I am unable to locate it!).
The old one is bent and I would like to replace it with a new one.
Can somebody give me the part number of it?

Thanks,
Ivo
 
Ivodispili said:
I have just noticed that the circlip on the mainshaft, behind the gearbox sprocket, is missing on the parts catalog (or, at least, I am unable to locate it!).
Click to expand...

If it is the clutch location circlip that maylar has posted the link to, then it is item 14 on the clutch drawing as it's inside the primary case and not behind the gearbox sprocket.
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
 
which tool should I use to install/remove this circlip without overstressing it? I have managed to remove it using normal circlip pliers and ... now it's shot!
 
Circlips are of the outward type and located inside the sleeve gear, see picture.

- Knut
 

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mdt-son said:
Circlips are of the outward type and located inside the sleeve gear, see picture.

- Knut
Click to expand...

However, it turned out to be the mainshaft clutch location circlip.
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
 
All right.

In another thread, someone proposed the use of circlip 06.0872 06.8072 as being better suited to locate the clutch. It needs to be thinned down to fit groove at the mainshaft.

- Knut
 
Last edited:
55.0872 appears to be quite different from item 14 that LAB refers to. Does 0872 actually fit into the recess of the Clutch Location Spacer?

A related post and the one Knut may be referring to is here.
 
Jdub said:
55.0872 appears to be quite different from item 14 that LAB refers to. Does 0872 actually fit into the recess of the Clutch Location Spacer?
Click to expand...

Well spotted but the alternative circlip part number is 06.8072 (not 06.0872, or 55.0872).

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

(I think 55.0872 is a Norton rotary part)
Edit: Yes, it is.
 
Last edited:
L.A.B. said:
Well spotted but the alternative circlip part number is 06.8072. (not 06.0872, or 55.0872).

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

(I think 55.0872 is a Norton rotary part)
Click to expand...
Use the stronger clutch location circlip and make it thinner by circling it about on emery cloth on a very flat surface. Stop when you can push it tightly into the main shaft circlip slot from the side . Then slide / push the clip over the main shaft to the slot and tap it gently all around until fully home. It's a clip for the E-starter I believe. The original clip crushes too easily if you exceed 40 ft. lbs. on the nut .
 
My original post on this:

The clutch location circlip (06.0752) is a bit notorious for being pushed out of its groove when tightening the clutch nut.

I use the circlip off the electric starter, which I think is 06.8072. Perhaps LAB can confirm ?

The ecectric starter circlip is a bit fatter than the standard circlip and needs to be thinned on emery paper to fit the groove.

HOWEVER WATCH OUT: THE 06.0872 CIRCLIP IS VERY DIFFICULT TO FIT AND A TOTAL B*STARD TO GET OFF AGAIN

And don't forget:

If you tighten the clutch centre nut up to 70 ft.lbs as per the manual it can crunch the circlip (06.0752)
on the main shaft causing the clutch to sit inboard and be loose. Most advise to tighten to 40 ft.lbs.
 
Staytite said:
If you tighten the clutch centre nut up to 70 ft.lbs as per the manual it can crunch the circlip (06.0752)
on the main shaft causing the clutch to sit inboard and be loose. Most advise to tighten to 40 ft.lbs.
Click to expand...

The Mk3 Workshop manual was corrected and states torque of the mainshaft nut 40 to 50 ft.lbs.

Edit: This applies to the rhs only, according to the manual.

- Knut
 
Last edited:
Yes it's a bugger to slide over the main shaft and lock into place after the thinning. You thought a Norton would be easy-peasy ?.
 
L.A.B. said:
Not in my paper or any online copy of the Mk3 manual that I'm aware of.
Mk3 gearbox: mainshaft circlip
Click to expand...
Nor in mine, which I bought last year from AN. I used the standard circlip, bought from AN and tightened mine to 70lbs/ft, before I knew any better and it has been fine for 5,000 miles.

I had clutch slip for 1000 miles or so and was in and out cleaning the plates until I gave up and replaced them, which sorted it.

I think Knut is referring to the amended mk3 service manual maintained by Chaztuna? Not saying the new way of doing it is wrong, just that the original way has not yet caused a problem.
 
Mart UK said:
Not saying the new way of doing it is wrong, just that the original way has not yet caused a problem.
Click to expand...

Yes, if the circlip is new or at least in good condition then it should (just about) hold 70 lbs./ft. but it has been known to fail, probably due to the circlip being reused too many times.
 
L.A.B. said:
Yes, if the circlip is new or at least in good condition then it should (just about) hold 70 lbs./ft. but it has been known to fail, probably due to the circlip being reused too many times.
Click to expand...
I sure as hell did not on my '74.

Nipped it up to 70 ft.lbs., and because I always do a cursory rotation test, saw the clutch drunk-wobbling right away. Took it back off to see a rolled out of shape circlip.
Twice.
Perhaps poor quality parts? (Material/heat treatment substandard)
 
Last edited:
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