1974 850 MK II Norton Commando Clutch Basket Advise Needed

Hi:

I am working to get a 1974 MK II 850 Norton Commando back on the road. On inspecting my clutch basket, it appears that the only medium holding the clutch backing plate in position, (to the clutch basket) are two rather weedy looking (and in my case rather worn) roll pins. Looking online I see numerous pictures of Commando clutch baskets with what I believe to be three drillings for rivets, (in addition to the two holes for roll pins). Neither my clutch basket or clutch backing plate have the three drillings, just the two holes for roll pins. Further online "research" suggests that because I only have the two holes for roll pins, that I have a 1971 or older clutch basket and clutch basket backing plate? In case you are wondering, a previous owner committed many sins on this bike, that I am working to put right. It would not surprise me at all if an early clutch basket was installed by a previous owner. Other than described above, the clutch basket appears to be in very good condition.

Assuming that my deductions are correct, I am wondering what is the best way forward? I presume that my current setup is probably inadequate for an 850? Can I get my clutch basket modified? If I have no choice other than to spend a bunch of cash to buy another clutch basket, I am wondering if I should consider a belt drive instead?

Thank you!

Kind regards,

James

Britstuff said:

Neither my clutch basket or clutch backing plate have the three drillings, just the two holes for roll pins. Further online "research" suggests that because I only have the two holes for roll pins, that I have a 1971 or older clutch basket and clutch basket backing plate?

Click to expand...

Yes.

Britstuff said:

Assuming that my deductions are correct, I am wondering what is the best way forward? I presume that my current setup is probably inadequate for an 850? Can I get my clutch basket modified?

Click to expand...

The rivets are available so it should be possible to rivet the early pinned backplate to the drum.
"Ron L:
Be advised that the plate and basket are extremely hard and will be difficult to drill with just a standard drill press and cobalt bits."

Whenever someone installs a cNw belt drive or e-start, they have a clutch basket leftover. There are quite a few on eBay right now. Also, a new one from AN is about $350 delivered and that has the backing plate already riveted on.

The cNw belt drive: https://coloradonortonworks.net/belt-drive-kit.html is certainly an option and it's an excellent kit.

From the NOC Commando Notes

The drum itself is made of case-hardened steel, and with many more splines than the centre so there is no tendency for the plain steel plates to notch into the drum The innermost friction surface on early clutches was a separate steel plate located by two tiny little roll-pins in blind holes in the back of the drum. Once the clutch was together this was O.K, but if the pins came loose (as they did) it was almost impossible to put the thing together and locate the backplate properly. It was also impossible because of the hardness to drill through the roll-pin holes so that proper rivets could be fitted-unless you had access to fancy equipment for spark erosion, but it is possible to tack-weld the back plate in position if you grind a couple of notches in the edge of the plate so you can get in with arc-welding equipment without spoiling the splines. Later the drums avoid the problem by having the back plate held in with three rivets to start with. John Hudson has advised that there is no need to re-rivet or weld this plate in, just remove the remains of the pins and let the plate do its own thing, quite safe.

John Hudson

Excellent! Thank you all for your input. That is exactly what I needed to know.

Cheers,

James