Buggered if I know the answer to this

Ged67 · Sep 11, 2016

This one is a bit of a mystery that I am hoping a Norton expert out there will have an answer for.

I have a 1974 Commando 850 The engine though appears to be a 1975 - it's engine No. 333915, it has a Presolite electric starter BUT the gear shift is on the right side.

I was thinking it was a Mk III engine but all of the reading I have done suggests that the Mark III was only ever manufactured as left side gear change to meet US requirements.

Any ideas or thoughts as to what is going on here?

cjandme · Sep 12, 2016

Re: Mark III 850 with Right Side Gear Shift?

Pictures....we need pictures

Most likely thing is that the P.O. swapped out the cross shaft gear shifter and gearbox cover and associated foot controls, others have done it. Fellow forum member Danno has a Mk3 that he reverted back to right side gear shift.

Rohan · Sep 12, 2016

Re: Mark III 850 with Right Side Gear Shift?

With those numbers its also possible its had a Mk 3 engine slotted into a Mk2,
so you may have to look closely to see quite how that has been done.

What number is stamped on top of the gearbox ?
That should tell you if its a Mk2 or Mk3 box, since the gearbox
number would have (initially) matched the engine and frame plate.

Ged67 · Sep 12, 2016

Re: Mark III 850 with Right Side Gear Shift?

cjandme said:
Pictures....we need pictures Most likely thing is that the P.O. swapped out the cross shaft gear shifter and gearbox cover and associated foot controls, others have done it. Fellow forum member Danno has a Mk3 that he reverted back to right side gear shift.

Interesting idea. I've come to old bikes after riding newer ones so the right side down for up pattern is foreign to me. Of course there are heaps of riders out there that started with that so the shift to left side up for up would have felt so strange.

Ged67 · Sep 12, 2016

Re: Mark III 850 with Right Side Gear Shift?

Rohan said:
With those numbers its also possible its had a Mk 3 engine slotted into a Mk2,
so you may have to look closely to see quite how that has been done.

What number is stamped on top of the gearbox ?
That should tell you if its a Mk2 or Mk3 box, since the gearbox
number would have (initially) matched the engine and frame plate.

I'll have a look when I get home I a few days and let you know.

Danno · Sep 12, 2016

I have a Mk III engine with right side shift. It has been converted from left shift. One could also put a Mk III primary drive with electric start on an older model 850, so yours may have been done either way. For a possible clue, look at the engine cradle to see if it has the gearbox/primary chain adjuster or drillings for the same.

grandpaul · Sep 12, 2016

I, too, converted my MkIII to right-foot shift and retained the e-start by simply plugging the holes in the primary.

It simply wouldn't do, to have a left-foot-shift custom Norton.

Ron L · Sep 12, 2016

Danno said:
I have a Mk III engine with right side shift. It has been converted from left shift. One could also put a Mk III primary drive with electric start on an older model 850, so yours may have been done either way. For a possible clue, look at the engine cradle to see if it has the gearbox/primary chain adjuster or drillings for the same.

Converting a MkII 850 to MkIII primary would require a lot of work. The crank snout is longer (would need to use the MkIII item, the inner primary mounting holes will not align and I believe you would have to do some mill work to either the left crankcase or the inner primary (not positive about this). In any event it is more work than I would want to do for a marginally functioning starter system.

An Alton or CNW kit would be much better.

cjandme · Sep 12, 2016

Ron L said:
.......... In any event it is more work than I would want to do for a marginally functioning starter system..........An Alton or CNW kit would be much better.

True, but both of those are only relatively recent kits.

Danno · Sep 12, 2016

Ron L said:
Danno said:

I have a Mk III engine with right side shift. It has been converted from left shift. One could also put a Mk III primary drive with electric start on an older model 850, so yours may have been done either way. For a possible clue, look at the engine cradle to see if it has the gearbox/primary chain adjuster or drillings for the same.

Click to expand...

Converting a MkII 850 to MkIII primary would require a lot of work. The crank snout is longer (would need to use the MkIII item, the inner primary mounting holes will not align and I believe you would have to do some mill work to either the left crankcase or the inner primary (not positive about this). In any event it is more work than I would want to do for a marginally functioning starter system.

An Alton or CNW kit would be much better.

Never said I wanted it or advised anyone to do it, I just said it was a possibility. The OP is trying to figure out what he has. I removed the factory electric starter because IMO, it's a bunch of semi-functioning dead weight and if your bike isn't in tune enough to start with one kick, you've got work to do. And If you can't kick it one time, you should probably stick to cars.