Buying a Norton Commando

[DBD34GS]

I`m thinking of buying a 1975 Mk111 850 Norton Commando with electric start. Being a Goldie owner I know sod-all about the Commando. Is there anyone that can tell me what to look for in a good Commando? other than the usual.

[L.A.B.]

Is there any reason why you specifically wanted an 850 MkIII model (not that I think there's anything particularly wrong with the MkIII model as I own one) or is it just a case of that particular Commando being available and offered at the right price?

The Mk III Commando electric starter was always considered to be a bit underpowered-but there are a number of starter upgrades available, so it may be worth finding out if the electric starter has been upgraded if electric starting is one of the main reasons why you want a MkIII (however MkIII owners often completely removed the electric starter mechanism). 

Front brake upgrades are also a common and desirable Commando modification, as the standard Commando (not just MkIII) front disc is rather wooden and not very powerful.

For lots more Norton Commando information, I suggest you go to the Access Norton forum:  http://www.accessnorton.com/

Certainly check the "usual" things-such as excessive smoking, knocks, rattles, misfiring, bad starting, etc...     

[DBD34GS]

Hello L.A.B.
Many thanks for the information. It is the electric start and the disc brakes front and rear that appeals. I have since been reading many reports of starter and brake upgrades. The information is very useful
Regards
DBD34GS

[rogerwilko]

If tou do get one ask how many sprags he's gone through. ,and be prepared to convert it back to points if you don't want expensive starter problems. Most have been converted to electronic ignition that don't like low voltage with the voltage drop with starter engaged.

[L.A.B.]

If tou do get one ask how many sprags he's gone through. ,and be prepared to convert it back to points if you don't want expensive starter problems. Most have been converted to electronic ignition that don't like low voltage with the voltage drop with starter engaged.

Electronic ignition technology has moved on, and only the old Boyer analogue Micro MkIII ignitions are likely to cause problems now and not the analogue Boyer Micro MkIV or any other modern electronic system such as Pazon or the Tri-Spark Classic Twin system (which has a built-in anti-kickback feature).
Sprag breakage is often caused by a badly adjusted starter drive backfire overload clutch which was originally fitted to protect the starter drive from backfires caused by the points ignition! Admittedly, some 850 MkIII owners seem to experience more starter problems than others. http://www.oldbritts.com/e_start_backfire.html

The Alton Norton Commando electric starter (and alternator) kit will be available shortly-so any non-electric start Commando can be converted to electric start with the Alton kit. Old Britts already have a starter conversion kit on the market however it's more expensive than the Alton and the Old Britts kit also requires some machining of the original parts to fit it whereas the Alton is a simple bolt-on conversion.   

[Welsh Wizard]

Make sure it has a metal tank not a fibre glass one  ( fibre glass and E5 or E10 petrol don't mix well)
also check Isolastics for cracking easy enough to replace but costly.
check head bearings in the yokes and also, have a quick look at front to rear wheel alignment, if it out it will show what sort of mechanic has been working on the bike, and show how the rest of the bike will have been maintained internally, ( only a guide but can be helpful with price.)

[L.A.B.]

Make sure it has a metal tank not a fibre glass one  ( fibre glass and E5 or E10 petrol don't mix well)

Thankfully, glass fibre tanks were already illegal (in the UK at least) by the time the 850 MkIII models were sold.

check head bearings in the yokes

1971-on Commandos had sealed non-adjustable headrace bearings which generally cause no trouble (provided water hasn't got inside them) but something to check.

[Welsh Wizard]

Thankfully, glass fibre tanks were already illegal (in the UK at least) by the time the 850 MkIII models were sold.

Yes but I saw plenty added, specials as well as damaged steel ones replaced by cheaper fibre glass ones from the auto jumbles, so its still worth checking

1971-on Commandos had sealed non-adjustable headrace bearings which generally cause no trouble (provided water hasn't got inside them) but something to check.

Sealed head bearings still fail , seen plenty wrongly fitted and some even over tightened

[L.A.B.]

1971-on Commandos had sealed non-adjustable headrace bearings which generally cause no trouble (provided water hasn't got inside them) but something to check.

seen plenty wrongly fitted and some even over tightened

That could apply to just about any steering bearings of any bike and is one of the "usuals"?  However the 71-on Commando steering bearings are not usually known to cause trouble due to the fact that 1, they're sealed (so require no lubrication and owners can't lose half of the balls) and 2, they are non adjustable-so it's practically impossible to overtighten them unless an owner does something drastic (such as leave the spacer tube out?).