Date: Fri, 28 Jun 1996 14:44:42 +0100 (BST)
From: D.J. Walker
Eric,
Like most of the British bike industry's output, the Commando was the subject of continual improvement, year on year, as the factory rectified the faults that had caused bits to either fall off or break in the previous year's output. Typical "use the customer as the tester" attitude. As a result, the later the model you buy, the stronger it is liable to have been built. In addition to various obvious and well known modifications, there were detail improvements, such as stronger gearbox components, fitted on the later bikes which are less obvious to the eye, and which many Commando owners are unaware of. 1974 onwards is about the point where they'd got things more or less right. The Combat, which had imediately preceded this model year was generally considered a faulty motor (but when detuned, they are likely to be as solid as any other 750 engine). The high stresses in the Combat model had revealed several weaknesses which were subsequently improved upon. These are the key improvements made to the Commando range. Superblend main bearings are the most notable of them. (The rollers in a superblend are barrel-shaped, and thus offer a greater area of support for the crank than ball bearings, while allowing greater flex than plain rollers would.)
Late 1973 is when the first Mk1 850s were built. '74 saw the Mk2A, and I'd aim for this as the bike of preferance. The 850 is a heavier bike than the 750, and is alledged to be somewhat slower as a result, but it does have several advantages. The most notable of these is that the bigger barrels are held in place by four huge allen bolts. The array of 7/16th and 1/2 sized nuts around the base of the barrels serve only to hold the barrel base gasket in place. This is a much stronger arrangement than is found on the 750s. The 850s also have spin-on oil filters on the return feed to the oil tank. This _can_ be added to earlier bikes, but the 850s have them as standard. There is also a sump-strainer immediately infront of the oil pump to protect it from the larger pebbles that find their way into any engine. I think this disappeared briefly, in '73... Refer to the post of last year, which described all the various models of Commando (whilst leaving out one or two obvious changes, might I add!). This is included in the Brit-Iron FAQ, I think. I don't have a copy myself.
The model sequence for the 850s is a lot simpler that that of the 750s: it goes Mk1, Mk2, Mk2(A) and Mk3. This can have the not-so-obvious advantage of making parts-ordering a lot simpler. (The Mk2 and Mk2A differ only in the quality of paint used, I think). The electric start Mk3 model of 1975-77 has several advantages over its other 850 predecessors, which might sway your mind (the electric starter is _not_ one of them.)
They are:
Boyer electronic ignition systems are generally considered a Good Thing. If the bike you're looking at has one, consider it a plus factor in it's favour. However _fitting_ a boyer system in a job that would take a maximum of half an hour, I'd guess, so don't be put off if the bike hasn't got one, just use the fact as a lever to bring the price down.
Single carb manifolds can be retrofitted to all the Commandos, and a variety of carb options are available. Any of these are, in all honesty, preferable to the twin Mk2 Amal systems originally fitted. Single Amal carbs offer greater fuel efficiency: VM Mikunis offer greater reliability (single and twin Mikuni options are available). Single Delorto systems can be had; they're expensive, but they do offer greater accelaration and improved pick up than the original twin Amals. None of these options allow for the retention of the original airbox.
Fortunately, Commandos don't attract spoke-counters and other anorak-types, so if you suffer from anoraknaphobia, you can modify your Commando to your heart's content without worrying about being taken to task for it at a later date.
If you're going to be doing a lot of touring on fairly fast roads, the
optional extra-tooth engine sprokets might be useful, to lengthen the bike's
legs a little bit, although remember that by lowering the ratio in this
way, the stress you take away from the engine is put onto the gearbox.
If you intend to ride through towns and villages or on narrow little back
lanes, a standard 19-tooth sprocket might be preferable. They give about
5000rpm at 80mph; a Commando motor can take that kind of treatment all
day long. Since the whole primary
drive/alternator system has to be removed to swap these things around
it would be preferable to have the sprocket you _want_ in place, when you
buy the bike.
The Interstate fuel tank, with roughly 4 gallons of fuel capacity (depending upon which type of "gallon" you use) is also useful for long voyages (like, umm, Inter_sttate_ voyages, I suppose) and although different types of Commando differ only in the type of tank, seat and side panels used on them, Interstate tanks are very hard to come by, secondhand (they are now being remanufactured new), so it would be best to buy an Interstate model, if that's the one you want, rather than change your mind at a later date. Fibreglass fueltanks should be checked for, and avoided..
Some people prefer the slimmer looks of the Roadster tank and sidepanels. Even the minute tank of the Hi-Rider doesn't look too bad, if the hideous banana-shaped seat and apehangers have been replaced with more normal items. If they are your preferance, you might be able to compensate for the lack of fuel capacity by improving efficiency, with a single carb option and fitting a 20, 21 or 22 tooth drive sprocket, as I mentioned earlier.
Modifications you might do to an 850 bike yourself might include changing the exhaust system. On the 850 this differs from the 750's in having a balance pipe across the front, linking the two downpipes. This can be prone to excessive rusting around the junctions and makes fitting and removing the exhausts more difficult. Furthermore, the balance pipe can restrict airflow over the cylinder head and, because it uses collets to locate the downpipes in the exhaust ports, the screw-in exhaust roses have less thread-contact with the ports. This is an area of weakness on all Commandos (and indeed its Featherbeded predesessors): the threads in the exhaust ports can strip. The deeper you can wind your exhaust roses in, the less the likelihood of this occuring, so the 750 system would seem preferable. Fortunately the unbalanced 750 system will go straight onto an 850 head, but you'll need the 750s exhaust roses, with their deeper threads to do this. They are more expensive than they ought to be - about 15 pounds, over here, as I recall. The unbalanced system is a little louder than the balanced system and a bit rortier-sounding.I think it looks better, as well.
Lots of other modifications exist, and the range of improvements is
almost limitless. My own bike has:
Best of luck. Whatever bike you get, you'll enjoy riding it.
Commando Dan
Date: Sun, 30 Jun 1996 02:49:53 +0100 (BST)
From: D.J. Walker
Dear All,
Further to my message of Friday about Commandos, etc. I thought I'd send a wee correction, regarding carbs. I said the standard system was two Mk2 Amals, when in fact it was, of course two Mk1 concentrics. I have no idea whether this has been commented on by anyone since then, as I've had nothing from Brit-Iron since Thursday night. Indeed the note I sent entitled "Commandos (long, long note)" was bounced back to me by Owner-Brit-Iron on the grounds that someone's mailbox was full somewhere between me and Indiana. God knows where: I only have one PhD, which is not enough to decipher the three or four pages of useless junk you usually get attached at the begining of bounced e-mails. Is everyone else getting their Brit-Iron as usual? Is the whole world conspiring against me as usual? I hope so, as any change now would be catastrophic for my daily routine.
Please could the individual in the Chicago bay area who mentioned my messages regarding my local Outlaw Chapter to their own local Chapter please stop doing so, as I was taken to task by my local Chapter president for - I guess the phrase is: "compromising his annonymity". What I actually said revealed no more about the bloke concerned than what reading several issues of BSH might tell you, but he is of the opinion the Internet is swarming with coppers (by which I mean Peelers, y'know, bobbies, fuzz, boysinblue, pigs). It is certainly true that the global village is a damn sight smaller than some of us are yet aware of.
I might, for instance, bad mouth a totally hypothetical parts-supplier by the name of "Mick Jennings", whilst still seeing fit to buy certain non-critical frame parts, such as, say, exhaust mounting rubbers off him (we're speaking of a totally imaginary situation, of the kind which is, of course, unlikely to have occured at any time during the last two weeks).
Commando Dan
Date: Sun, 13 Oct 1996 02:03:18 -0400
From: Mike Taglieri
>Ever since high school, I have coveted the Nortons my friends rode.
I would
>like to buy a "daily driver" 73-74 Norton 850 commando between now
and next
>spring. I seek a low mileage bike which I can slowly clean up and
improve.
>
>I also seek wisdom from the list:
>
> what are clean Norton's going for?
> Are there any "achille's heels" I should look for when checking out
a
> used Norton?
Wise idea to limit it to those years, since most of the "achilles' heels" were in the '72 and earlier. There are no probblems in Nortons that can't be fixed, but generally the later the better. I've reposted below a long post I wrote a couple of years ago on what to look for. It also incorporates some corrections other people added to it then.
Incidentally, I often tour on my Norton. Maybe you meant you're just sick of touring, but if you get a British bike and fix it up carefully, it should be reliable enough for touring.
Mike Taglieri
Raul -- '72 Commando Interstate
Date: Wed, 18 May 94 23:42:41 EDT
From: Mike Taglieri
>Saturday I am going to go look at a '73 Norton 850 Commando,
>excellent condition, 6000 original miles, $2500. Ex. cond., low
>milage, Where could you go wrong. Ah! There's the question. What
>should I be looking for in the inspection? Does this bike have a
>favorite place to blow a gasket, crack the frame, rust solid,
>etc. Any advice would be welcome.
Unlike brands that had years of flawed frame design and other major problems, all Commandos are basically similar, and there's nothing you can't fix. My '72 Combat, for example, was from the absolute worst year in terms of reliability, and arrived DOA with 3 burned valves after only 6000 original miles. The '73 already has most of the improvements I've added to my '72, including the box-section head steady, camshaft bearings that bits won't break off from in the engine, a real spin-off oil filter, and above all, Superblend main bearings.
Therefore, you're really looking for things you'll have to fix, not some hidden doomsday fault that can't be fixed. Here's some things I'd check (some of which are the same for all britbikes, not just Nortons). You should also take a look at the INOA Tech Digest, which lists the improvements made every year, though by '73 they mostly had been made: