Sunday 20 March 2011

BSA 500 Twin

When I bought the 1960 BSA twin it was in a pretty rotten state. Never restored nor renovated, just patched up over the years when and where necessary. I could still tell from the lines of the bike that there was a class act somewhere under all the mess. The engine, some 87000 miles old, still grumbled into life. The whole machine was just far enough to the right side of being a rolling wreck to let me ride the 35 miles home.

One of the reasons I went for the 500cc version of the venerable pre-unit engine was because it was reckoned to be the sweetest running of the bunch. Not plagued, like the 650, with hand and foot numbing vibration. That was the theory, anyway, and it may have been true for a newish, carefully run in machine. My old crate rattled and vibrated, come 50mph, like there was something about to fail.

Combine that with suspension that was way past its best, the springs practically down on their stops, to deduce that by the time I arrived home I was not in the best of moods. The previously full oil tank was all but empty when I checked it out. The rapidly forming puddle under the bike explaining that disappearing act.

All that hassle and the bike had cost nearly a thousand notes. Even in the recession, finding anything that ran for that kind of money had taken nearly six months of hard work. I had come across worse bikes for twice the money! I knew it would cost heavy dosh to do a full renovation...... what I had in mind was a quick tidy up and doing the serious stuff as I went along. That was three years ago and the bike is just about completed

The first weekend I tore off all the bits of chassis that would come off. Every bearing in the frame needed replacing and the mudguards were revealed, by the way they fell apart, as having more rust than metal. The seat pan went the same way. Charming. Bearings from the local factor, some old guards from the back of my garage and a bit of metal bashing to the seat sorted the worst of it. Then it was just cleaning off all the corrosion and painting or polishing.

That took about two weeks to complete. Tightening up the engine bolts, adjusting the primary chain slack and setting the valves and ignition went some way to damping out the vibes. Nothing I could do for the oil, except grin and bear it. Rode the Shooting Star in this condition for about 3 months.

Top speed was limited to around 60mph by the combination of vibration and wallowing. Either on its own would've been annoying, both together made the bike a right bitch. Water also had to be avoided. The SLS drums filled up with the stuff, braking fading away to nothing. Not that the brakes could be called good, requiring hand breaking muscle just to produce minimal retardation. The water also got into the electrics, stalling the bike dead in potentially dangerous situations.

The easiest thing to fix was the suspension. All it needed was some stronger springs in the forks and a pair of Girlings I just happened to have stashed in the garage. The bike would still bounce about over rough going, but was generally stable, none of the nasty weaving and wallowing. The frame was heavy grade steel, thus strong even after 30 years of abuse. The bike was also good on tyres, taking to just about any cheapo, half worn rubber the breaker had on offer.

The ride was on the harsh side, neglected country roads giving my spine a real pounding. The slight slackness in the forks produced a nasty bit of juddering under harsh braking - but that only happened once a day because the front brake needed a good 24 hours to recover. The shoes and linings were not too bad, still some life left in them, I guess it was just the progress of time that made them seem really antiquated.

This honeymoon period came to an end on a perfect summer's day. The kind of day when you want to ride and ride down deserted country roads. I was feeling one with the world, doing about 35mph in top on a completely empty road. Then there was a mild knocking noise which rapidly turned vicious with very harsh vibes running through the chassis. My hand was already pulling in the clutch as the engine seized solid. So gravel rash time was avoided, although the long push to a telephone box was not. I cursed the heat of an English high summer.

Turned out both the roller and plain main bearings had gone into self-destruct mode. The remains of the engine that weren't mangled were worn out. Old age had finally caught up with the venerable BSA. Ever since I bought the bike I'd been courting an acquaintance with a lovingly rebuilt engine going nowhere in his workshop. He didn't have the dosh to buy a rolling chassis but lived high on the dream of one day reconstructing the machine of his fantasies.

I only got the motor out of his oily grasp by making the offer in the presence of his wife. One look from her when he was about to refuse 600 sovs soon changed his mind. This started out as a 1958 unit but had been so completely rebuilt that putting a year against it was utterly pointless.

Getting the old engine out was much more of a struggle than putting the new one in. Mostly down to seized in engine bolts. Perseverance and a wicked way with the lump hammer finally freed the beast. Whilst I was all fired up with enthusiasm I decided to rewire the bike, hopefully making it less suicidal in the wet. The wiring was a real mess, over the years most of it replaced with the wrong colour and grade of wire. Use of an ammeter and a bit of luck got everything working again.

In this state, the engine's 30-odd horses were good for 85mph on the clock, but not for long. The vibes were just as bad past 70mph, below that tolerable for a couple of hours cruising. Acceleration was on a par with a CD175, although there was enough grunt to dump the engine in third or fourth. Surprisingly, the gearbox was as smooth and precise as most modern Jap bikes. The action was heavy, though, not the kind of device that could be operated when wearing trainers. The way vibes limited speeding had a payback in economy (around 60mpg) and long lasting consumables.

Handling was fine up to about 75mph, thereafter the weaves were wicked enough to indicate that the frame might be bent. I had never fallen off the bike, despite the dreadful brakes, and the wheels looked like they were in line. Maybe if I splashed out on a brand new set of Avons the machine would be transformed at higher speeds, but the vibration made high speed such a rare occurrence that it never really bothered me.

The vibes (and the dreaded rust) eventually left me with a groin full of petrol. That was another summer's day, about a year later, and another long hot walk home. I took the hint, three months later, tore the whole chassis apart for a thorough renovation job. Most of the bearings I'd replaced before were shot again.....only about 8000 miles done. Did most of the hard work myself, picked up some rough guards and other bits to renovate along the way. The finished job is smart rather than immaculate.

By the beginning of the next motorcycle season I was ready for the road with a worthy bike. Since I acquired it, the motor has done nearly 12000 miles. No major problems but it does need a service every 400 to 500 miles. And I had one primary chain snap, wrap itself around the clutch with expensive results. I also had to buy a renovated set of forks as the old ones had so much slop I didn't think I could safely restore them.

The BSA is not my essential means of transport. If it was I would be in deep trouble. Anyone who thinks otherwise is living on another planet. I enjoy my weekends and evenings riding the bike in good weather. Takes me back to my misspent youth.

Pete Collings