OWNING A Commando

For me, becoming a Norton fan all started in Toowoomba in 1977. I bought a basket case Commando. Can’t remember the model year but it had Dunstall livery. Took me 6 months to build it and start riding, including a couple of Toowoomba winters. Everything needed some repairs as baskets always do, they wouldn’t be baskets otherwise. For the most part all went well until I tried some Mikuni carbs, in place of the worn out Animal carbs. It took a while but I got it to work OK as they were off a 2 stroke. Way too rich. Rode that around and eventually did a Bathurst trip, a Tassie trip 2 up and a few years later a trip to Cairns. I sold it and then came a fastback and then a Roadster and then an Interstate. Each one got a full going over, of course, they too were baskets. Now there are a few in the shed, mostly funded by building and selling lots of baskets, mainly Triumph and Norton over 40 years. I’ve been trying to build one of each model for a while now. I have on the build, a 1968 Fastback, a 1969 ‘S’ Model, a 1969 ‘R’ model, a 1972 ‘SS’, a 1971 Highrider, Nortons answer to the chopper craze, a 1971 Long Range Fastback, a one year only model, using essentially an Atlas tank before the big tank Interstate. Also a 1972 Combat Roadster, a 1973 Interstate, a 1974 Interpol, as best I can figure and a 1975 E Start Roadster, maybe I’ll finish it this yr, a button for my dickie knee. I have the makins of a 1974 JPN not a real one but something close, it’s a Norton, with all aftermarket glasswork. Half are done and half are still happening. Also in the lineup is a Dunstall 1972 810cc, I picked up most of the bits from the Dunstall catalogue over 30 years at swaps and built up the rest of the bike from Commando bits found. A 1974 Norvil, most of the Norvil stuff to dress up a Commando is available new, unlike Dunstall. The last one of the period cafe bikes is a 1971 in Gus Kuhn body work. Basically the big 3 of cafe era.  Only about 6 of the Commandos I have are matching numbers. I have also built a few specials and of course they are built from found bits, not even a basket. I have a problem I know.

When I go through a Commando I like to pin the swingarm at the cradle to remove any slop with the pin which wears in the cradle not so much the bushes. Norton finally did this in ’75. I sometimes fit the later model Isolastic adjustable kits but it is not a big issue for me. The front mount is easy to drop out and reshim. I like to make sure all the engine bolts are very tight when assembling and will use a rattle gun. The bolts around the back of the engine can and do come loose, causing holes to elongate, affecting the handling. Not good for the primary case either. Keep an eye on them. Many times I have seen damaged primary cases because someone has not shimmed behind the inner primary to the centre bolt. Take your time and get it right. If you have it down to the frame I suggest you add triangular gussets to the back loop like the later 850 if not already fitted. This was to try and stop the loop bending when loaded with a pillion. Especially when dressed as an Interstate as the tank is longer and therefore the passenger is further out over the back wheel. I tend to fit A65 63-70 shocks to any Commando I ride as they are ¾” longer and make the bike steer a bit better, a handy mod if you pillion. Again, if the frame is stripped, fit 30205 taper roller bearings to the steering head. A direct replacement for the ball bearings and spacer tube. Tightening the original ball bearings will do nothing. With the tapers you can give them some preload and minimise head flop which may cause a high speed wander. Norton forks work well mostly, if the trees are true. New better damping tubes can be had for the knee dragging crew but I find Norton Roadholder forks do just that. I use auto trans fluid. Every bearing in a Commando can be had at the local bearing supplier. Double sealed for the wheels of course.  6203 for the single row and 4203 for the double row.

                                                                                                                                                    I never bother with double roller bearings on the crank. I use a 6306 ball on the timing side as it has a dynamic rating almost as much as the roller on the drive side. With this heavy duty ball which has 10 or 11 balls, when fitted, captures crank end float, job done. If you are going to race you may wish to piddle with 2 rollers. The T140 Triumph and pre ’72 Nortons used an 8 ball 306 T/S bearing, not the heavy duty 6306 and some failures did occur. The early Commando used Atlas type pistons which had a shallow oil ring groove, difficult to fit and one could easily roll one of the rails into the bore introducing an unwanted groove in the bore. Trust me I know and rode my Norton to Cairns and back. Smoked a bit but went there and back quite well. Nowdays, pistons and rings are no problem for all the Commando 750 or 850s. Cast piston sets by  Hepolite or Emgo both made by JCC are a good thing. Hepolite rings are now made in the UK and are a better type. There are a few forged jobbies available also for a few dollars more, for the knee draggers. Nice chrome moloy steel conrods are available if one wishes to replace the aging stock aluminium rods. Good insurance. This would necessitate a rebalance, as would using forged pistons although checking the weight of the new against the old might see little weight difference so no need to rebalance. A dynamic balance factor of 52-55% depending on which expert you currently listen to, is a good ball park. The cylinder head is generally considered a goodun, reasonably narrow included valve angle and low combustion chamber, working with flat top pistons. The 750 uses 30mm carbs and the Combat 750 and all 850 models use 32mm carbs. The seats for the valves are cast in and made from Stellite, which are much harder than those found in Triumphs.  The valves are the same for both but the guides differ. Rarely if ever have I seen a loose guide in a Norton head, can’t say the same for Triumph twins. Generally new aluminium /bronze guides and black coated stainless valves are a good upgrade. These are available in oversized heads but I try to only go oversize on the exhaust valve if the seat has been cut a couple of times. There is not much seat area and using a 1mm or 1.5mm bigger valve head can restore the seat and installed height. The inlet is fine and I do not recommended  using oversize options  on both valves if a non standard cam with higher lift and longer duration is being used. They may tangle/clip during the overlap period. Hard to rectify with a single cam type engine. I had a cylinder cut open to see this. The short lived 750 Combat engine models were introduced for the American go fast market in 1972 but strangely they did a lot of them with the new Interstate touring tank, ummmm. These engines had higher compression and a performance cam necessitating the use of higher RPM. The newly introduced double roller main bearings sometimes failed in the race, from the flex of the crankshaft induced by the higher RPM. A fix was introduced with the Superblend roller with a slight taper to allow some flex and reduce race damage. As I don’t use the maximum 6000rpm recommended for the long stroke but short rod engine myself, I find a ball and roller pair is fine. Be odd to find a Combat engine with all the original internals. There are all sorts of performance upgrades for these engines if you purchase one. Primary belt drives, Mikuni single carb kits, long conrod conversion for more torque and more.                                                                                                                               As I’ve mentioned before, Electric Start kits can be had for pre MK3. The MK 3 from 1975 and ‘76 had US mandated left shift so the factory added a rear disc and a button. The button is a bit weak but can be upgraded to 4 pole – 4 brush which I did for Judes Commando, a bike made completely from scrounged bits of mixed years, with info on upgrading the starter.  British Bikes by Brian. In this video I showed a modern starter motor by Madigan. I recently fitted this to Judes bike after problems with the old original rebuilt starter surfaced after years of good service  and amazing things happened, stars shot into the sky, pixie dust falling everywhere, things went wiz and the bike was sitting there idling like magic.

With the gearbox some upgrades can be worthwhile if a look inside is needed. Circlipping the hi gear both ends to prevent the  bush moving,  if replacing the bushes with one long bush or an extra short bush and replacing the layshaft ball bearing with a roller. Some end float correction may be required if doing this. So find someone with a lathe to part off a steel shims for you, it would fit between 1st gear and its bush in the kicker shaft. With layshaft, 1st gear and kicker shaft in with gasket, measure the kicker end float. This also makes 1st gear engage better. Maybe a final drive gearing change. This depends on the use you have in mind. Wheelying around the streets or cruising on the highway. You can fit an Atlas gearbox shell in a Commando, I have 3 bikes in the shed so done. They are the same shell except the Commando top mount is narrower to allow easier fitment in the cradle. A spacer is then required. I have seen this spacer left out and just tightened up bending the cradle without really tightening the gearbox. Same bloke who doesn’t shim the primary no doubt. If there is a shim or spacer, like most Brit non unit type bikes, someone will leave it out and damage the primary or engine plates, for sure. The first few years of the Commando didn’t have a cush drive and one can sometimes see a bit of wear on the gears. Not a real problem though. The Commando clutch is a big pressure plate held by a big circlip. A tool is definitely needed to avoid personal damage. Remember to remove the clutch pushrod before fitting the decompressor.

The 1972 year saw the first disc brake and stainless guards used until the last model. The front guard was wider than the previous years which were chrome and now hard to come by. Replacement S/S guards are reasonably priced.  Dunlop 4.10 x 19 were fitted Fr and Rr with these wider guards. I prefer the 3.60 x19 front with the 4.10 rear, if staying with a 19” rear. A respoke to 18” rear is a fair option given the better tyre choices one would have. The brake can be made better and I think in 1972 as it was their first disc, Norton dumbed it down. Upgrades can include braided lines, better pads and a small bore retro fit kit for the master cylinder, increasing pressure. Many Norton riders fit the Triumph caliper with an available adaptor plate. In the UK there are some incredible floating single and twin disc front ends for them.

Keeping the exhaust on is something the factory didn’t waste to much time pondering. The Xover tube from ’72 helped but one has to be careful as the available thread for tightening is halved. Often there is a tang clip that will stop a nut from unscrewing out but the nut can still loosen some, vibrate and wear the thread. I suggest at least adding a cross brace between the muffler clamps and maybe some sort of spring to keep the exhaust nut from undoing. I normally fit a clamp on the pipe and an ‘L’ bracket to the front engine mount, Triumph style, bit rough? but the pipe stays on. The main thing is to buy a decent exhaust nut tool, I use a 2 finger BMW type and it is the best. A pipe wrench or hammer and punch seem to have been the preferred tools in the past. The shim guy again. The frames changed in1971, different fork yokes and steering stops on the frame and different centre and side stand arrangement to name a few.  Frames were basically 68-70 then 71 to 76, with minimal changes. The first in ’68 had recalls as the factory design was without a gusset tube at the steering head. Some frames broke. Seen two, have one. Lots were replaced and some repaired but some may still be out there. Check carefully if looking to purchase a ’68. You can make anything work really, so the whole Commando era is interchangeable, kinda, with work. The ’71-’76 period  allows easy body changes given the guards are stainless, so a Fastback, a Roadster or an Interstate, all with one basic bike.

Anyway this could go on and on, I think they are a good thing and are very capable machines especially if a few upgrades are done.

Cheers,           

Brian