Buyers' Guides

Thursday, 14 January 2021

DIY Brits

Could you build a bike from a box of bits and end up with a good looking and reliable motorcycle? Well, there can't be many interested in British machinery who haven't played with the idea at least once in a while.
Understandably too. For those wanting a good example of Britain's finest without paying the inflated prices of the "vgc low mileage classic" or the "very reliable one owner from new," it certainly has its attractions. The potential savings are enormous when buying a basket case or just a non-runner.


But, can the novice really be expected to build up his own Brit bike to the right spec and the right price? Well, despite all the warnings from those who are in the know, and their grisly tales of financial and mechanical disaster, there are an ever increasing number of successful projects being wheeled from the garage by first time rebuilders.


So don't be put off by the horror stories, and remember, if I can do it, anyone can... I first saw my “box of bits" in the pub car park. It had been cleverly disguised as a motorcycle and was parked half blocking the entrance, so that no-one would miss it. Inside, the middle-aged enthusiast and his chums were bellied up to the bar; the air thick with big valve heads and racing camshafts. My wife and I swapped knowing looks with the landlord, and headed for a quiet corner just as junking the air box raised another cheer.

Later, we accompanied the boys outside to give the bike a once over. The owner told my wife it was an eight fifty Commando, ex police and therefore very fast, luv. He'd just been for a spin round the Lakes on it this morning. He started up the bike, valves clattered, pistons slapped and exhausts smoked. I doubt if it had been further than the end of the street that morning. A few months later it was mine,albeit in a slightly different condition.

Lesson one for novice rebuilders: Strip the engine. Regardless of what the vendor tells you about it just having been rebuilt, or not requiring attention. I had been assured there were no longer any problems with the engine. During the strip down, however, I couldn't help noticing knackered rings and heavily scored pistons and bores, worn out valve stems and guides, one lobe seemed to be missing from the camshaft and all the nuts holding the crankshaft together were, er, loose. In the unlikely event of the engine running in that condition, those loose nuts could have caused a serious accident. Which if not to the Emergency Ward then would certainly lead to the point of lesson one: Putting anything other than a thoroughly checked engine into the rebuilt chassis is very dumb.

A friend put me onto the machine. He knew I'd gone all soppy over British bikes, and, in his usual confidence inspiring way, he whispered that the owner might be willing to let it go - "The bike's all ready for putting together but he doesn't have the time, pressure of work and all that, you see." (Some of you may have heard that before). Barring an exhaust system, most of the important bits appeared to be there. So I took it for three hundred quid. When it turned out that a fair amount of work on the engine was, in fact, needed the next thing was to get hold of the right parts for the job. This also involved the learning of lesson two: Buy your spares from someone who knows what they're doing. If they are not familiar with the machine and you haven't much idea either, you can expect to end up wasting a lot of time and money.


The shop I visited first had been recommended by my friend. He let me know they had most of the bits I required, and of course they knew all about old Brits. I was later to discover from his wife that my friend has never actually ridden a British bike, let alone owned one. In fact, he only noticed the shop when they were towing the caravan up to Scotland for the summer holidays. I asked for chrome stemmed valves and cast iron guides, which is standard for my model, and was fairly chuffed when they were ready to hand. Not so chuffed later though, when the valves turned out to have just plain stems and weren't a very good fit in the guides. But here comes the best/worst bit. When I took them back the bloke snarls at me and says, don't be bloody stupid if they put chrome on the valves it'd bloody peel off

Somewhat disappointed with the chap's lack of manner and technical knowledge, accepted a refund less the customary 10% (for doing business with blockheads). I rushed home to telephone the order for the right stuff to a reputable shop in Gateshead. Ordering from the specialists must be the best way to obtain those crucial spares. And these guys who're happy to give you all the advice you'll need, can usually get the bits to you in a couple of days.


Once the right parts started to arrive the engine rebuild started and my enthusiasm was rekindled. Soon I was in the mood for a trip to that great institution of the British biker, the auto-jumble. I'd never imagined there were so many different shades of brown. There were thousands and thousands of used parts set out on the stalls, and damn near every one was rusty. The grand auto-jumble at Belle Vue was totally overwhelming for a first timer like me. And after an hour or so of gawping at all that brown, I was suffering chronic brain fade and had all but forgotten what I was looking for. Which is probably why I snapped up the pair of chrome headlamp brackets, which were one of the few things I could see as being right for the Commando. The asking price was £7.50 and they looked in good nick, especially amid a sea of dead chrome. I pulled out some money and they were quickly wrapped up in newspaper. You've guessed it, when I unwrapped them at home the good finish was on one side only. The lesson here is quite obvious, but it's nothing new, indeed it's becoming traditional for first time jumblers to get ripped off. If the price of experience really is failure, the novice would be well advised to leave his fat wallet at home until he's made a few mistakes of his own.

I had gone to Belle Vue in the hope of trading the police chronometer speedo for a pair of original type clocks. And maybe pick up an Interstate tank. However, it wasn't until my seventh or eighth jumble that I finally found what I needed. The one and only Interstate tank I came across was a bit scabby and not cheap at twenty five quid. But a pair of unused Smiths clocks were a snip at twenty quid plus the chrono.

A friend did his usual unapproachable job on the tank. After rust removal and dent filling, he used a twin pack paint to quickly and easily produce a deep lustrous finish, which doesn't show up irregularities the way cellulose does. Meanwhile, back at the ranch, armed with a Black & Decker, industrial mops and grits (those hobby kits are a bit crappy), the alloy was cleaned up to something like showroom condition. With the rolling chassis prepared the engine and gearbox were slipped in with a nice new set of Isolastics. In short, the box of Interpol bits had been transformed with not too much hassle into a fair looking Interstate.


One dark Friday night, after learning to start the thing in two or three kicks, I crunched into first and we were off. First gear was very tall despite dropping to a 21 tooth gearbox sprocket. To modify the AMC box (originally designed to handle a 30hp five hundred) Norton had done little more than slip on a bigger sprocket every time they upped the engine size. Owners will know that this did little for the longevity of the layshaft bearings, the 22 tooth sprockets beat the hell out of them.

A clutch which alternately slipped under load and dragged when I tried to change gears was something new. But the carefree pogoing of the rear end was all too familiar, yet another pair of DOD (devoid of damping) shocks. After a few minutes, when the engine had begun gassing up on small throttle openings, I returned to base for some adjustments. The clutch didn't improve and the plugs revealed a massively over rich mixture.

Over the next few days problems came and went. Inspection revealed the bronze clutch plates had acquired a thin coating of burnt on oil, but they responded to scrubbing with solvent. Installed with a mug full of 10W40 in the chaincase, subsequent operation was just fine. The rich mixture was not so easily solved. Engine vibes had enlarged the needle jet in the Amal carb. If you don't know that the average life of such a jet is a mere 10000 miles it does take a while to suss it out.

But after all this, I have an excellent condition, reliable British classic; which goes rather well with a black helmet and flying jacket. All for a total outlay of £850. I've enjoyed myself so much I think I'll do a Bonneville next. Unfortunately, this probably means the Commando will have to go, although my wife does have an apt solution. Arrange for it to be exported to Japan is what she suggests, they seem happy to pay top money for good quality Brits. And what's more, Tojo isn't going to come round knocking on the door wanting his money back when it breaks down. Anyway, if he does I'll want a word with him about my Honda camchain...


Malcolm Ingham