Mk3 gearbox: mainshaft circlip

[Ivodispili]

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

 

[maylar]

https://andover-norton.co.uk/en/shop-details/15399/clutch-location-circlip-mainshaft-

or this

https://andover-norton.co.uk/en/shop-details/16416/circlip-sleeve-gear-bush

 

[L.A.B.]

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!).

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.

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[Ivodispili]

Tanks a lot to Lab and Mylar, that's exactly what I was looking for!

 

[Ivodispili]

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!

 

[mdt-son]

Circlips are of the outward type and located inside the sleeve gear, see picture.

- Knut

 

[L.A.B.]

Circlips are of the outward type and located inside the sleeve gear, see picture.

- Knut

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

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[mdt-son]

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

 

[Jdub]

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.

 

[L.A.B.]

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?

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

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

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(I think 55.0872 is a Norton rotary part)
Edit: Yes, it is.

 

[Torontonian]

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

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)

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 .

 

[concours]

....and torque to 40 ft. Lbs

 

[Staytite]

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.

 

[mdt-son]

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.

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

 

[Torontonian]

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.]

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

Not in my paper or online copy of the Mk3 manual that I'm aware of.

https://nortonmotorcycles.org/media/manuals/850_man.pdf

 

[Mart UK]

Not in my paper or any online copy of the Mk3 manual that I'm aware of.

https://nortonmotorcycles.org/media/manuals/850_man.pdf

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.

 

[mdt-son]

Not in my paper or online copy of the Mk3 manual that I'm aware of.

https://nortonmotorcycles.org/media/manuals/850_man.pdf

My tunnel vision struck me again ..... you guys are correct.

- Knut

 

[L.A.B.]

Not saying the new way of doing it is wrong, just that the original way has not yet caused a problem.

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.

 

[concours]

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.

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)