My initial reason for this brave act was to replace the leaking head gasket. I found things in such a bad state that I doubted if I could stick the head back on and start the beast again. Both exhaust valves were heavily pitted, the rockers were loose and the piston heads were heavily scored. Removal of the cylinder revealed broken oil rings and bores with deep groves. One of the pushrods was bent. The crankshaft wobbled on its bearings. The more that was revealed the more I began to wonder just how the BSA had run before. I decided to get serious and perform a full rebuild.
Having access to a friend's workshop (equipped with a lathe and milling machine) meant I was able to do most of the work myself. In fact, I became so enthusiastic that I ended up improving the engine rather than just replacing bits out of the parts catalogue.
I also acquired a box of bits, which had new barrels and pistons and various other useful bits. I replaced the weak main bearings with a couple of roller bearings. This required boring of the crankcases to take the heftier bearings. The crank, itself, was still in good condition, and as I had no intention of tuning the engine, I left it well alone, except for cleaning it up. A new gasket set combined with Hermetite were used to stem the oil leaks. I bought new bits for the head and a set of lightweight pushrods. Everything was polished up with Solvol, then oiled and thrown together, a process that turned out to be surprisingly easy. This left me with the engine complete and a rattly primary drive. I also wanted to replace the horrible dynamo with something more modern.
I decided belt primary drive was needed but didn't fancy paying out £300 for a conversion. The amount of space available made fitting in the width of a belt difficult, but by redesigning the clutch basket I was able to just fit in the narrowest belt I could find that would take the BSA's 40hp. I don't recommend this to DIY enthusiasts as it took three attempts to get the engine sprocket right and two attempts to make the clutch body. I had to have the grooves for the belt made by an outside specialist. Total cost, including wasted alloy billets came out at £145. But it works > and makes the engine both quieter and smoother.
I managed to find a fairly small Lucas alternator but couldn't mount the thing. I ended up gutting the dynamo, machining a new body to take the Lucas bits and combining them with the drive from the dynamo. If this sounds difficult, I can assure you that it was, but I was unemployed in this period, so could spend lots of time solving various problems. Unfortunately, when I had it tested at the local auto-electricians it didn't work. But this was found to be caused by a duff Lucas rectifier (they stick 'em inside the alternators on cars). The gearbox was left alone except for new, thicker oil.
The carb was new but stock and a set of pattern pipes and silencers were bunged on. It took seventeen kicks to start, and the tappets sounded like they were a hundred years old. I had set the exhaust clearances much too big. Fixed that and it came to life first kick.
At that time, I didn't do much to the cycle parts because I wasn't so sure how the engine would perform with the modifications - I just cleaned them up and patched up the rust spots. After five thousand miles and no big problems I decided to smarten up the old girl with the aim of making it look as stock as possible, a bit of a street sleeper. As I didn't want the bike off the road for long periods I renovated the cycle parts one at a time, using some of the bits I had laying around rather than tearing the bike apart. This caused the odd problem when I came to fit the renovated piece as it wasn't exactly the same as the old bit and I didn't like whacking a newly painted surface with a hammer. I soon learnt to check that the spares fitted before working on them. Anyway, after about 6 months I had a bike that approached showroom condition. All the new paint and chrome even made the bike seem to run much nicer.
Starting, aided by a brand new magneto was relatively easy as big vertical twins go. If the weather was mild, it'll come to life first kick (or rather bodily lunge on the kickstart). Very cold weather needed three or four goes, The mildness of the cars and ignition timing means it rarely kicks backs (just check the magneto timing every 2000 miles), but you do have to get the engine just past compression before making the kick. I did lend the bike to some youth who had only started two stroke Jap bikes, and he actually came limping back without the bike. His ignorance had allowed the bike to kick back and he received a bleeding and bruised shin.
Indeed, amongst local bikers all kitted out with this Jap crap the Beeza rather stood out and despite its relative slowness, the occasional young girl insists on going for a spin on the pillion. Unfortunately, the better half rather frowns on this kind of socialising and threatens to dump two pounds of sugar in the petrol tank if I venture beyond strictly defined limits of propriety. Still, what the eye doesn't see...
The valvegear still clatters loudly enough to fail various noise laws, but this becomes lost once the bike gets going as the silencers are rather misnamed, but the noise isn't that offensive, compared with two stroke howl or four stroke four wail. Rather like Morris Minors, A10s bring out past owners, who witter on about the good old days and the police don't come on nasty, even the cop on a BMW who found it very hard to keep up with the BSA on my local country lanes. I forgot to mention that I'd the fork internals with stiffer springs and used better shocks than standard, when he stopped me he was quite shocked when I told him it was a stock '58 bike, and didn't book me for speeding.
Handling is stable up to 70mph, a mild weaves intrudes for the next 20mph, then it becomes stable again. The weave gets no worse even on very worn tyres. Indeed, you can fit just about any tyres without upsetting stability. Weighing a little over 400lbs and with a short wheelbase, the bike is no slug when scraping the stands or frightening car drivers in town. Some young whipper snapper on a RD350LC once took me on the inside of a long bend, but he ended up on the wrong side of the road and I then took him on his inside - it was better than choking on all those two stroke fumes.
Such is the low speed torque that it'll hold that speed up hill and down dale. There's also plenty of engine braking, which is helpful because the SLS drums aren't much use above 50mph. I did fit a TLS front brake, from an A65, but this juddered and didn't stop the bike any faster - I think the drum must be oval. I'm on the look out for something better but it has yet to turn up. The front SLS brake is very progressive, it's just that after a 70mph stop it becomes too hot and the next application results in rapid fade. Changing down through the box ‘helps, but at least the bike can still be manoeuvred during braking. A go on a Kawasaki GPz550 soon convinced me that there was a great deal of room for improvement.
Leaping back on the BSA, half a mile later I went into the side of a Fiesta when I forgot just how much room the BSA needed to stop. The A10 had a scratch or two on the front mudguard whilst the car had a large dent in the door, door frame and sill. Nice of these car companies to make their cars so that they absorb all of the shock. Another advantage of riding a BSA is that you have to dress the part, which together with the noise and brutal nature of the bike means Joe Public is shaking in his boots after he's been foolish enough to put his car in your path. I soon convinced the Fiesta driver that he had bent my frame and should hand over a hundred notes to facilitate repairs - he had admitted to having no insurance himself.
Maintenance is relatively easy and requires no special tools. The rebuilt BSA engine doesn't shake itself to bits. for the simple reason that I Loctited every nut and bolt on the engine. I check over the valves, ignition timing and carb every 1000 miles, but more often than not they don't require attention. I replaced the belt primary after 25600 miles, and the new one has done 15000 miles without any problems. That's a total, so far, of over 40000 miles with no real mishaps, since the rebuild.
Fuel averages 60mpg, but I do 80mpg if the money's short or 50mpg if the right hand is hungry. Oil consumption is a pint every 250 miles and, shock, horror, it doesn't leak any oil (well, OK, a small drop from the gearbox casings but I haven't stripped that yet).
The rear chain is a real scraggy item, which when I summon up the money and enthusiasm I'll swap for an O-ring item (it means getting someone to make new sprockets to suit the chain). It only lasts for eight thousand miles - I fear that sidecar trauma past has left things a little out of alignment (the pulling to one side, however, mysteriously disappeared after I'd taken the chassis apart) leading to the need for constant adjustment. I could obtain longer life by taking out a link or two, but to my mind when a chain has reached that state it's due to break at any moment.
There are still some annoying habits. The footrest rubbers vibrate off however I try to glue them on. The Amal carb also becomes upset by the vibes and deposits petrol over the engine. The bike can be blown way off line by strong side winds. And the exhaust clamps come undone every 500 miles. Although the engine polishes up nice, most of the chrome on the pattern parts is lacking in staying power - I have to spend more time polishing these bits than on routine maintenance.
The stock bike with chain primary drive and dynamo vibrates more and has absolutely pathetic lighting - the kind of stuff that knocks 50% of speed off when riding in the dark. Try tuning a standard bike and the mains will be shot, the vibes become really nasty and the whole gentle character of the A10 will be lost. You have to forget all about those stories of British twins ruling the roads. It's just not on these days, the poor old A10 is hard pushed to keep up with a good 250. That's in the short run, in the long run with a couple of sensible mods the bike keeps going long after the Jap stuff had dissolved in its cheap alloy (is it easier to repair a Brit crankshaft than a Jap cylinder head ? Ed).
My hairiest moment came when the rear wheel disintegrated. This, I think, was caused by its abused past when it had to cater to the stresses of a sidecar. Anyway, I was running along at 60mph when a wobble appeared at the back of the bike. I thought it was just a puncture and lost speed pronto. By the time I was down to 30mph, the whole back end locked up solid and the bike slewed to a halt. The seat height had been drastically reduced and I had quite a shock when I glanced over.
my shoulder.
The rim was a funny square shape and the squashed spokes were sticking outwards. I was fifty miles from home with no idea what to do next. Just as I was about to dump the bike in a ditch, a van pulled up, the owner recalled that he used to own one just like it and he knew a Brit bike shop ten miles down the road. We dumped the bike in the back of the van, drove to the shop and, yes, they had a used wheel. An hour later the bike was back together and I was £20 poorer. That's British biking for you.
Cliff Hutchings