I have owned, ridden and played with many a motorcycle in the last twenty years. The only one that has stayed the course all that time is a 1971 Dunstall 750 Commando. I bought the bike in 1975 with just 4000 miles done. Cynics might suggest that such a paucity of mileage was caused by the Commando engine's liking for self destruction, early examples being reduced to mechanical wreckage well before the warranty expired. But they would be wrong, at least in this particular case. The motor had been carefully rebuilt by the Dunstall crew, fitted with mild cams, low compression pistons and a single carb. The one owner was aged and obviously had trouble draping himself over the large tank on to low clip-ons.
Commandos, at that time, had received lots of accolades from the press and only had to deal with wimpy Honda 750 fours and insane Kawasaki triples. I had just tired of a Honda CB500 four, which although civilised was bland to the point of boredom. Which certainly couldn't be said of the Norton, it had all the character of a particularly crazed baboon, leaping about at tickover like the engine was about to pop out of the frame, whilst chattering along at 5000 revs could in no way be called relaxed. The Commando was part of a brash, brave new world where the maximum amount of enjoyment had to be extracted for the least amount of effort.
That may seem a wild thing to say about a big Norton twin, but the 750 was in such a mild state of tune that it could be bunged in fourth and rolled off from anything but a standing start on the throttle. Not that the angle of the clip-ons nor the heaviness of the clutch encouraged you to play around with the heavy, slow gearchange. The trick was to lurch the brute into fourth at the earliest moment and let the torque slog it out against the 400lbs of steel and alloy. Riding most other bikes after the Norton, was like being forced to have sex with a condom after enjoying the real thing.
In those happy days, with loads of money coming in and nothing much more than motorcycles to spend it on, I usually had a couple of machines in the garage. Which will explain how the Dunstall did less than 30000 miles in the next ten years. Apart from regular vaive checks and oil changes every 2000 miles (the bike had electronic ignition) in that time I did not even have to tighten down the head bolts. Starting off with an engine that was put together properly and in a reasonable state of tune obviously helped longevity.
The Isolastic mounts did a lot to help damp out the ferocious vibes that a British twin of this capacity would normally produce. The Norton was never actually as smooth as a similar capacity four, but most of the destructive effects of the vibration were successfully absorbed by the mounting system. Any engineer, except those working for Norton, would have isolated the motor rather than both the engine and the separate gearbox. Given that you have one of the few pre-unit engines still in existence it would have been the obvious thing to do. Norton, however, decided the whole unit had to be isolated, leading to an arcane shimming system at the swinging arm.
This piece of engineering malpractice needs attention every 1000 miles or so and leads to the owner going bald, kicking the shit out of stray cats and becoming generally anti-social. Failure to attend to the shims, or, worse still, get the clearance wrong, leads to either excessive vibration or a chassis that weaves and wanders all over the road like a decrepit dhow in heavy waters.
Handling is generally par for the course for a British twin when the shims are set up properly. The Norton doesn’t change line as fast as a Bonnie, but weaves less in rapid curves and has a bit more suspension movement, which helps over modern, rutted road surfaces. The Dunstall comes with twin front discs that are harsh enough to twitch the forks and cause a few moments of concern on wet roads when their hesitancy is often quickly translated into a locked up front wheel. The age of the machine is revealed by the way the calipers are mounted in front rather than behind the fork legs.
The Dunstall’s seat is a gratuitous piece of violence on the rider, going hard after as little as 25 miles. Placing a heavy pillion on the back had the seat buckling all over the place, the GRP base finally deciding it'd had enough, snapping off and throwing the poor old passenger off the back. The way he was jerking around with all the elan of an ace kendo artist indicated that something was seriously wrong; he didn’t fall off until I'd got the speed down to 25mph!
I carefully picked up what was left of the seat before I went to his aid. I had to phone a friend to come to collect him, he so dazed that he was wandering around in circles muttering something about it being time for tea. Poor chap, refused thereafter to go near anything with two wheels. The seat was repaired with a bit of steel plate for strengthening and some GRP. As the unit contained the rear light and a useful space in its hump, it would not have been so easy to replace. I did add some foam to the seat but it was basically too poorly shaped to help cushion one’s weight. Also, so high that it left me perched atop the bike looking rather ridiculous, whilst the big tank spread legs in a way that only some decadent young lady would enjoy. I usually had other bikes that would serve as long distance cruisers, so it was no great loss. I usually enjoyed myself immensely carving through country roads on the Norton.
The Commando is one motorcycle that could never be called epicene, its character more macho than the most egotistical of Essex men. Even painted azure blue by the past owner, it was not the kind of motorcycle you could easily dismiss, the cement mixer exhaust note made damn sure of that. Even in its mild state of tune it would still put 120mph on the clock, doubtless aided in that feat by pulling very tall gearing and having a svelte half fairing that allowed the rider to crouch out of the wind.
Any wimp who got close to the Dunstall would soon be put off the idea of ownership by the amount of effort needed to fire up the motor. Even with electronic ignition and mild compression ratio it steadfastly refused to come to life on anything less than three gut churning kicks. Sometimes it took as many as ten kicks and you always had to be a licentiate in the language of gentle encouragement. Any belief you might have in this kind of heavy metal being a living, breathing creature was confirmed by its need for endearments every time you went near the kickstart. Swearing. or cursing at the Commando would result in one solidly dead motor.
I soon grew used to the mechanical patios needed to keep the machine going. If neglected on a run, it would stutter, threaten to stall on you, until some words of encouragement worked their magic. Call me mad if you must, all I can say is that it worked for most of the time. The Norton grew most distressed when subjected to the usual deluge of water. In the early days it would often grind to a halt, sit their sulking whilst I swore my head off and threatened it with the largest spanner my tool roll held. I knew it was a narcissistic brute that would not at all like having its shiny surface dented. Actually, all it really wanted was some decent HT caps, relocated coils and the occasional dose of WD40.
In 1984 and 1985 I was deeply involved in an affair with a cafe racer Z1 which had a turbo charger bolted on. The frame had been much strengthened and the boost from the turbo was even more exhilarating than the low speed torque of the Norton. Consequently, the Dunstall was rather neglected for these two years, its once shiny alloy oxidizing in protest to a degree than would shame a 20 year old Honda. It indubitable character had responded by refusing to start unless the motor was kicked over at least 30 times - I usually gave up after five and caressed the Z1 into life on the button instead.
When the Kawasaki finally blew its innards every which way I had to reluctantly convince the Commando that it was once again the centre of my attention. It didn’t respond until I'd cleaned up all the alloy, given it a new coat of paint and fitted a set of spark plugs. Although it started OK after that, a bout of punctures had me cursing and swearing again.
With nearly 35000 miles done, I was trundling along in town in second gear when some jerk in a Volvo slammed on his brakes. As the road was clear the only possible reason he could have for such an insane act was to make me fall off. I braked harshly then threw the bike around his hideous auto, letting loose with the throttle. If nothing else, the exhaust noise would blow his eardrums away! With a large grin on my face, I held the throttle wide open in second. With the rev counter flirting with 8000 revs a tremor ran through the machine with such intensity that I backed off instantly and fingered the clutch lever.
The bike still ran but it sounded really sick, so I gingerly rode the two miles home, looking out for a Volvo to kick. I whipped the valve covers off but couldn't see anything obvious. Off with the head for the first time. Bent exhaust valves, ruined valve guides and a cracked piston. Could be worse, I consoled myself. Unfortunately, it was. Took off the cylinder to find that the small ends were gone, the pistons were scored and the bore worn heavily at the bottom. Then I noticed that the con-rods were a bit loose on the crankshaft and that, er, the crankshaft itself rattled about on its main bearings. Bloody hell!
I knew the bike was down on power a bit, that it had rattled and knocked somewhat more than I would have liked, but I would not have guessed that the engine was so worn out from the way it had been running. That night I had to be physically restrained from going around the town battering Volvo cars to death.
This was the one time in my life when I didn’t have a running machine in the garage. I‘d sold what little was left of the Z1 off for a pittance and had been laid off at work. Norton parts were readily available new but I would have to spend a few hundred quid to put my machine to rights. The small ads in Classic Bike turned up a good crankshaft, con-rods and pistons, so I only had to pay out for new valves, guides and a rebore.
Nothing is straightforward, though, I managed to get the valve timing way out and was lucky not to have ruined the new valves. The engine didn’t actually start, so I was able to save the day. Old Brits have to be carefully run in when rebuilt, so a gentle saunter up the Welsh coast seemed ideal. As it was high summer the roads were chockablock with caravans; I don’t know who felt most disgruntled at our slow pace, myself or the Norton. I had to lope along in second with just a hint of throttle for most of the time, which meant the engine shook in its lsolastic mounts like a pneumatic drill.
I was overcome with neuritis after the first day. When someone tapped me on the shoulder from behind I jumped about a yard and I was shaking like someone in the throes of an epileptic fit for the rest of the night. For some reason, this recreated engine, even when thoroughly run in, never achieved the levels of smoothness of the older bike - perhaps the Dunstall had its original crankshaft dynamically balanced.
For the next two years the Commando was my sole machine, doing 18000 miles in that time. Riding more than a 100 miles in a day was certainly no picnic. The hard seat, harsh vibration and crippling riding position combined to make me lumber around like a woman about to have a miscarriage. The suspension had also started to flop about, so I'd bunged on some really harsh Girling shocks that were trying to live out the rest of their life in a quiet corner of my garage and put about a pounds worth of steel washers in the front forks. I was thrown about like a jockey doing the jumps on a particularly violent horse.
A new job meant a fast commute across town was necessary, something the Norton objected to as the gearbox was playing up and the clutch had become so stiff I needed to keep on a course of steroids to cope with it. A test ride on a GS125 revealed a whole new world of smoothness, civility and pavement hopping, so I borrowed the bread from an ever compliant bank manager, this before the feud broke out between banks and their customers. The Norton was sidelined to the back of the garage during the week, only’ seeing the light of day on sunny weekends.
It objected to such ignorant behaviour by burning the whole electrical system to a frazzle. The battery usually only lasted for a year, anyway, and was due for replacement. The alternator was a charred mess, as was the Zener Diode, rectifier and large capacitor. The wiring had melted to an extent that made me lucky the bike had not been consumed by fire. All this happened sixty miles from home. I had to push the bike two miles to a farm, convince them I wasn't an Hell's Angel about to rape and pillage the place, leave the bike there whilst I hiked and bussed back home to convince a mate that it was his duty to take his rat Bedford van on a perilous journey to collect the Norton. He broke down on the way back, but was in the AA, so the mechanical duo were safely carted back to our town.
The Norton was left to languish for nearly a year. I even took the GS on some long runs, quite amazed at the way it coped with such distances in a comfortable, quiet way. But | could not quite bring myself to sell the Norton, I had too much of a sentimental attachment to this machine even to be moved by the large amounts of dosh they were beginning to fetch. I slowly picked up the necessary electrical bits over the months and eventually rewired the bike.
That was three years ago, the bike now has just over 62000 miles on the clock and is still running OK. It’s had a new exhaust system, oil tank, some better suspension and the rear wheel re-spoked as it started breaking up. It won’t do better than 50mpg or 105mph, these days, although that lovely wide burst of torque is still there for the taking. I took the gearbox apart to find some teeth missing off the cogs which were replaced with good used ones. A new, nylon lined, clutch cable has lowered the amount of hand muscle required.
I also reluctantly ditched the fairing and put on some more comfortable bars that don't threaten to wreck my back or kill my wrists off. With a better seat the machine would just about make it as a useable tourer, but the way the engine rumbles past 70mph in top means it’s really no faster than the little GS125! To be honest, the machine is way past its prime and probably due for another major rebuild before it gets to 65000 miles. It says a lot about the sheer character of the beast that I’ve already got all the bits waiting for the moment of decline!
Dave Crutchly