Wednesday, 28 March 2018

Norton Commando

A brief faltering in forward motion led me to halt and park the bike, a bored out 920cc Mk5a Norton Commando. Erratic reliability is not uncommon with British vertical twins, I thought to myself. My angst on this occasion was unfounded because smeared around the rear wheel rim were deposits of German salami. Said item had fallen out of the various packages adorning the rear of the bike which could only loosely be described as luggage equipment.

Huge panniers and excess weight at the rear do upset handling and if you want a really exciting time, fit a handlebar screen as per the Highway Patrol. The only other time handling was truly thrilling was due to 6lb tyre pressure in the front. I have fitted an Interpol type fairing and things are generally OK with this. Handling is fine with loads of ground clearance with only slight vagueness from the front end on long sweeping bends at high speeds. Whilst not in the Featherbed class, it does track around bends well - usually, I find that I lean more than is needed.

Early UJMs are nicely gobbled up in any swervery, the last being an XS1100. The state of the art race reptiles are another matter and put me in the moped class! There is much debate amongst owners on handling and Commandos do seem to vary a lot... my engine is not shimmed especially tightly in the Isolastic mounts, the tyres are ribbed Roadrunner at the front and the standard one at the rear - I've never come close to a tank slapper. Strange, that the bike can keep going so well in the wet, when riders of more modern bikes are backing off the throttle and fretting away not sure when the tyres are about to let loose. 

Most British twins are like that, designed to be ridden in all weathers (tested as they were in merry old England rather than arrid Japan), the combination of torque inspired power and surefooted roadholding meant the rider was usually aware of what was happening between tyre and road. It would be interesting to see how well the latest tackle went on old fashioned tyres... worth trying if you have a death wish.

If only the hassle free handling was matched by the engine! This is definitely not a fit and forget component, the latest little foibles being a broken timing chain and a blown head gasket. To be fair, these malfunctions can be attributed to an engine rebuilt by a cowboy. Split link timing chains should not be fitted to Commando engines and the gasket should not be copper (fit composite ones). No problems since. The Commando engine had an initial reputation for rapid self destruction that was only cured when specially made Superblend bearings were designed for the crankshaft. There can be few bikes left that have not been converted by now. The other problem was a weak contact breaker and advance/retard mechanism that used to vary the timing in an amusing manner - electronic ignition solves this one.

So why was I slicing salami on the Kent coast at 7am on a wet October morning? Well, I'd just rolled off a trans channel special after a trip to Germany. You might well consider this to represent boundless optimism combined with stupidity. Certainly, the German lorry driver I shared a layby with somewhere in the Ardennes would have agreed. He watched as l attacked the exhaust pipe lock-ring with a brick - a well known Commando vice, loose exhaust nut clamp rings. Usually, a special C spanner does the business but the threads in the head were dodgy. something to watch when buying. Otherwise, regular checks with said spanner are in order. Cracked exhaust pipes, especially those with balance pipes and/or not made from the stronger original steel, are quite common. Stainless steel items are not a bad if expensive idea.

Anyhow, having demonstrated the superiority of British engineering, I continued with a memorable ride along the sweeping bends through hilly woodlands at a steady 80-90mph on nearly deserted roads. With the rev counter showing 4500-5000rpm, the engine felt bullet-proof, but this, of course, was a grand delusion produced by the lack of vibes and the sublime confidence of its exhaust note.

The euphoria ended somewhere in Northern France with a stall at the traffic lights and a subsequent refusal to restart. RIP killswitch, which after disconnection allowed further progress to Calais. The latter stages were covered in the wet at night in company with a crazy Renault 5 driver. Honour was satisfied, but only just.

This highlights the passage of time. When the bike was built it could happily burn off Avengers and Cortinas. but these days it has problems with modern cars on motorways. True, even now, it will stomp away from most vehicles up to 90mph, but then it all quietens down, with the bike struggling past 100mph. Prone on the tank restores some speed but it makes you look like a right prat.

Rubber engine mounts take out most of the vibration. It is, after all, an old design from the fifties with two huge pistons moving up and down together with no silly balance shafts. What is left is various strange sounds, shakes and rattles sub 2000rpm... l feel it is an acceptable price to pay for the relative smoothness of what is an archaic British vertical twin. A 21 tooth gearbox sprocket (bigger strains the gearbox) gives a cruising speed of 80mph at 4500rpm with some reliability. Sustained adventures beyond this and, say, 6000rpm through the gears guarantees a super quick wear out rate!

So my 1200 mile trip to Germany was not without incident, but the bike was good fun and it’s something a little bit different (though 50000 were made). The haul up the M1 at night to the Midlands was a real drag, something not helped by the alternator deciding to fade away, with the charge light only going out above 4000rpm. Eventually, I only reached home on the pilot light with the engine popping and banging away. Main beam was a good killswitch. A new rotor and stator cured that problem, but you have to pay attention to the gap between these items. The later, welded type, is rather more reliable than earlier alternators.

Mechanical competence is not a strength of mine but fortunately help is at hand. The spares situation is excellent with many parts better than the original ones and the bike is generally easy to work on (though, someone who tries to put the cylinder head back on for the first time might not agree - those pushrods). Most components, such as the electrics and gearbox, can be uprated and beefed up, as well as harder camshafts and various improved bits. At a price, they are no longer in the cheap and cheerful bracket, something which goes for the purchase price as well. There is also loads of literature, service notes and an owner's club. If you're over 25 you get excellent insurance value through the VMCC.

To be honest, the bike is a bit of a black hole given the money spent on it, with most major components having been renewed. As stated, this is the result of thrashing it. Treat it as a gentle tourer with perhaps the occasional thrash and active life is prolonged with much less cash. The amount of money and time I'm willing to expend on the bike says a lot about the rewards of its riding experience - oh yes, a days ride on a Commando leaves you with a lot to think about.

To finish off, here is some data. Top speed around 100mph (sitting up). 55-60mpg with an SU carb, 48mpg with a single Amal and under forty with twin Amals. 0-60mph in around five seconds on a good day. Front tyres last around 20000 miles. rears 7000 miles, chains about 8000 miles and primary chains 30000 miles. Boyer ignition is excellent and trouble free. save for a loose wire on the back of its mounting plate. The crankshaft assembly is original at 50000 miles, but Superblend bearings were renewed along with the camshaft and gearbox layshaft bearing at 41000 miles. And just like the Japs, it needs an oil change every 1000 miles. You see, you've got to work at it.

Michael Jansen

No comments:

Post a Comment

Note: only a member of this blog may post a comment.