Copyright (c) 2008 GoodMotorcycles.com
I don't know what it is about the BSA B25, but I love 'em, warts and all! The first B25 Starfire was introduced in 1968, an illogical prefix as it was an update on the C25, itself an evolution of the C15. The C25 was much more short-lived than the C15, the former lasting only from 1967 to 1968, whilst the C15 was initially introduced as the Star well back in the midst of time (1958).
The model actually goes back further than this, to pretty horrible things like the C10. The Star was bad enough and set the pace for future models. Designed as a very basic commuter, if the engine was ever used in anger the main bearings disintegrated in short order, and not much later the top end would give up the ghost. If you really wanted to pay a lot of money for a really terrible motorcycle you could buy a 1962 C15SS, laughably called the Sport Star, which, in typical British manner featured a tuned engine with the same crank as the C15!
The chassis on the C15 models was most certainly in the commuter camp, pretty horrendous things used to happen if you tried to do more than 50mph. It wasn't until the C25 Barracuda became available in 1967 that a decent set of forks and proper TLS brake were fitted to the 250 singles (although it is not a difficult job to fit these later items to earlier machines). The C25 featured lots of minor mods to its engine as well as a beefed up gearbox, the latter almost as famous as the crank for giving trouble in the C15 range.
The C25 was a reasonable bike up to about 60mph, beyond that its single cylinder OHV motor churned out enough vibes to make the contact breakers fall apart, but often not before they had had a chance to alter the timing sufficiently to burn a hole in the piston. The main bearings managed about 20,000 miles under mild use, less than half that when the throttle was wound on relentlessly. I have put 75mph on the clock of one of these beasts and lived to tell the tale! Handling was okay if you were young enough to take the stiff suspension.
Whilst I would consider spending a hundred notes on a C25, it's the B25 that really gets my blood flowing. The B25 was named after the successful trials bike, the 441cc B44, sharing with it many components as well as 12 volt electrics, albeit of a fairly basic kind. In fact, I have found the electrical system gives more problems than the engine on these bikes.
I actually had one bike catch fire when vibes caused the main ignition wiring to fall apart, short out on the frame, ignite some surface petrol which quickly spread to the GRP petrol tank (later bikes have a much safer steel tank, which should be fitted to earlier bikes as soon as possible). One moment I was happily thumping down the road, the next I had a fireball between my knees. I sort of stepped off the machine, watching in anguish as it rolled off the road, cartwheeling down a slope, bits falling off. There was nothing left worth lugging home.
The vibes really do get inside the electrical components. Even the alternator has been known to fall apart! Lights blow with tiresome regularity and the joker who fitted an ammeter in the headlamp must have been out of his mind.....it takes less than a 1000 miles to have the needle flicking back and forth madly. The rider is left sitting there wondering whether it's just the ammeter that's on the way out or if the whole electrical system is about to burn out. It makes the GS Suzuki series look like they have first class electrical systems!
My next machine was fitted with clip-ons and a full race Gander and Gray tuning kit. Top speed increased from a gut churning 85mph to an eyeball popping 105mph. With not much more than 300lbs to shift it was easily the fastest, nastiest 250 in my area. Engine life of this machine deserves a whole article to itself. I never got away with more than 4500 miles before a full, and I mean full, engine rebuild was needed. It once only lasted 2500 miles before the crankshaft started rumbling.
But it was fun, at the time I felt the ease with which the motor could be stripped fully justified its finicky nature. I only tired of the machine when the gearbox locked solid at 80mph! I was spat off the machine and scraped off the tarmac by the local ambulance crew. The bike was another write off with little left that could be salvaged. I went off motorcycles for a couple of years after that but was soon pulled back by a 1969 example in prime, low mileage condition. I just could not resist the sleek lines of the shining Starfire.
Even with the B25, the main bearings are dubious, you'd be a very lucky man to do more than 30,000 miles without replacing them. They rumble quite obviously when on the way out, getting noisier as the revs increase. Vibration also goes wild when the mains are worn, but as a good bike also vibrates fiercely at some revs you will need to have some experience of the breed to suss out a decent 'un.
Although my machine was low mileage it soon started rumbling. This wasn't down to throttle abuse but the fact that the oil had not been changed. Judging by its consistency it had been there since new. The B25 has a Japanese like need for 1000 mile oil changes, the neglect of such even more violent and nasty in its manifestation than on small Hondas and the like. Oil leaks were also present on new bikes, let alone the ancient hacks that these machines have become. The crankcase covers are especially noticeable in the way they allow large quantities of oil out of the engine.
After rebuilding my engine from the crankcase up it did about 15000 miles with few serious problems, then needed a repeat dose of tender loving care. The B25 does seem to have been designed in a way that encourages all its bolts to come undone. Loctite works after a fashion, but the engine mounting bolts come undone regardless of how much of the stuff is spread on their threads - a daily chore is tightening up these bolts. Neglect leads to the engine jumping about, taking great chunks out of the crankcase mounting lugs.
Another vibration inspired problem is the petrol tank falling apart - the two halves are not welded very well, tending to gradually allow ever increasing amounts of petrol to seep through the seams. The first I knew about it was a wet crutch. Not wanting to have a repeat performance of the earlier's machine passable imitation of a fireball, I bought a new tank. It took only 7000 miles for the same thing to happen again. Feeling brave I pointed the welding torch in the direction of the old tank, which solved the problem.
By way of contrast, the chassis gives few problems, is still up their with the best in terms of chuckability and stability and hasn't even cracked up under the fierce vibes it receives. The engine growls out its 25 horses in no uncertain terms, revving all the way to 8500rpm with little reluctance or plodding along in top gear at 30mph with no hesitation. Once used to the vibes the Starfire really is a delight to ride on any road other than motorways.
The swinging arm has grease nipples which needed pumping full of the thickest grease available every time the engine oil is changed. Apart from that it's just a case of keeping the tyres in more than 3mm of tread. Bald tyres make the bike do really lurid speed wobbles and it is also dead easy to throw down the road in the wet in such a state of neglect! Tyre wear is over 15000 miles, fuel consumption in the 75 to 85mpg range and chains do about 10,000 miles. If it wasn't for the yearly engine rebuilds it would be an exceptionally cheap machine to run.
I now own three machines that are rideable, one of which is really immaculate, the other two are useful hacks. I've got the bits to make another six, but have no intention of doing so, they are just my ultra cheap source of spares. I've never paid more than a 100 notes for any one machine. They used to be ridiculously cheap, but even now it's possible to buy a very rough one for about a hundred quid.
I can't really explain why I like them so much. I'll be the first to admit that the engine is far from reliable, but I derive a huge kick from riding my machines, chatting with other BSA owners and, I guess, going against the grain. If any readers want to swap engine parts for chassis components I'll be very happy to hear from you (write via the UMG), as I have an excess of the latter, including some straight frames. I aim to have enough spares to keep going well into the next century!
Derrick Davies
I bought a B25S Starfire (BSA not BSI as the lady in the insurance suggested, sweet young thing that she was). I travelled four hours up the motorway in a car I thought might break down any minute to see it. It was beautiful, the white paint gleamed, the chrome sparkled, the shape of the engine.......so, veiling my enthusiasm I started to go over the bike more carefully.
The forks shook about; slack headraces at the very least, but the bike was only £140 and then the nice man gave me £10 back towards petrol, which I thought rather generous.
Back home, I found I couldn't start it. Tried kicking it over, no good; it just lay on its side and grinned up at me. Seriously though, lunging on the kickstart either before compression or after did nothing. The seller had started it with ease but it took me ages. One of the perils of owning a highly tuned OHV single that BSA hadn't fully developed.
The sparkling chrome, however, was simply not there - the front rim was painted over rust and the rest was pitted quite badly. I consoled myself by patting the spare petrol tank and stripped the front end. Then I took a closer look and tried to work out what else I'd need to do. I knew it needed a new loom (excuse me whilst I wax lyrical about the simplicity of the wiring, no indicators, no block connectors, not a microcomputer in sight). I needed a new rear tyre as the old one had cracked sidewalls even though it had plenty of tread. Everyone called the front one a Slidemaster which wasn't very reassuring. I decided on new tubes and a Roadrunner which has behaved impeccably. Also, a new battery - I was told that batteries made in Britain were not available - and bulbs. The headraces were knackered and the fork bushes and seals had seen better days.
Once back in one lump I had a test ride and discovered it needed a new alternator. The new rotor had six magnets and was larger than before and the stator had nine coils, but the bike had only a two phase rectifier which may or may not burn out some of the coils. Still, it worked brilliantly, or so it seemed to me as I've always had 6V electrics in the past.
It came with a TLS front drum which led me to wonder why they ever fitted discs. Once set up properly it was ace. I bought a 12V coil, some nice drop bars and some Smoothrite for the frame.
After the test ride it seemed to be knocking and a strip revealed a 23 thou undersize regrind on the crank instead of 20 thou to suit the shells, so I had it taken down to 30 thou and fitted new shells. It needed loads of helicoils, too. A new gear lever and shaft completed the engine rebuild after a pattern part didn't work and the reclaimed BSA part was a little short. I painted the spare tank quickly, saving the old one for a decent respray, and took it for an MOT. Joy of joys, it passed and soon I was running in the new big end.
Eventually, I reached the magic 500 miles and eased open the throttle. Down the local bypass it was that fateful day, 60mph came up, then 80mph, then the ton and still it pulled. Seriously, though, it did do about 70mph and all on a 14 tooth gearbox sprocket (16 being stock). The wrecked and pot-holed roads showed just how these old Brits got their reputation for fine handling - it would hold its line over rough going but part of the reason for such accuracy was taut suspension that not even age and mileage had done much to diminish. Still, comfort apart, I was well happy with the way the bike held its line and could be flicked through the curves.
But afterwards a glance revealed oil all over the engine, so new oil seals were ordered and a plastic tube fitted to the gearbox breather. Another thrash and the top speed was down to a ring smashing 60mph flat out with a smoke trail to rival any two stroke - the exhaust valve guide had worked itself completely out of the head after the bottom lip had disintegrated. Luckily, OTJ supplied an oversize guide and I replaced the valves as the stems were both worn. The breather tube solved most of the oil leaks - perhaps I shouldn't have added STP to the gearbox.
Two days later, the gearbox refused to change out of fourth and I had to ride straight back from town cancelling my visit to the shops. The strip revealed a broken camplate spring, which I suppose must've been original and I had to fit Cords rings as OTJ didn't do ordinary +60 rings. These Cords do give excellent compression after a quick blast to bed them in, though a bit more expensive.
A local engineering firm charged £11 to ream the valve guide hole and it turned out it was oversize at the top. I also added a decompression plate under the cylinder to bring compression ratio down from 10:1 to about 9:1 as it was pinking on four star unless I added octane booster. Longer pushrods to match and I copied an idea from Classic Maniacs and turned the front, left-hand crankcase timing plug into a breather. I didn't go further and fit oversize valves and have the cam ground down to lower overlap and increase lift, but if anyone has I'd love to know how it performs.
The original design of the bike was quite good, let down by the usual lack of attention to detail and production quality. Even brand new these bikes were rumoured to self destruct rapidly, so the problems with my used and abused example are pretty common stuff, although all the engineering skills already exist to turn the B25 into a reliable device; indeed, the bike was uprated and updated in CCM form and many superior bits from this engine can be employed if you've got the money to spend!
Now, I can't say I've been completely faithful while all this has been going on. I've dreamt of a Morini 350, I've lusted after a YPVS and lately a CBX has seemed like a good idea. The B25's kickstart was becoming a bit lazy in returning so I ordered a new spring - as the suppliers are having some more made it didn't arrive in time for the rebuild, so rather than wait I put the bike back together. Sure enough, three kicks and it broke; temporary replacement, a bungee cord. Patience is a virtue.
Tips: A 100 link rear chain just fits with a 17 tooth gearbox sprocket (47 rear) and that's after using the chain for 400 miles - I'll have to prestretch the next one, but the bigger gearbox sprocket gives the bike a much better feel and a higher top speed - there's little point revving the balls off the engine as it either breaks or causes bodily harm from the vibes, when anyway it pumps out torque at reasonable revs. Why are Reynolds chains so difficult to buy, the other stuff isn't hardened?
Torque Seal secures the alternator rotor if used on a third of the shaft; too much and the puller damages the rotor. Using a Jubilee clip stops the puller slipping off and also makes a reasonable ring compressor. Don't reuse paper gaskets on oil filled cases unless you lust after major oil leaks. Silicone rubber makes for oil tight engines and Blue Hylomar stops petrol tank tap threads leaking. Pet Seal is good for temporary repairs to tanks. Oh, don't knife edge the bottom of the piston or the skirt doesn't get lubricated properly.
The bike has now cost about £650 including a metal petrol tank (as the painstakingly resprayed one leaked), so as cheap transport it has failed. But it handles beautifully, if rather firm in the springing, looks great in Hammerite blue and black, and only needs a front rim, a five plate clutch hub and a tacho to finish it off. Unless I find that CBX first.
Jim Marston
Over the years I've had the lot. The full range of post war BSA pre-units singles except for the B32 and B34 Gold Stars. Many in the know would argue that the Gold Stars are the only ones worth having, but with current prices of £5000 upwards, I'm never likely to find out. I've owned some of the later unit construction singles - C15, B40 and the like but the less said about them the better - they just give British iron a bad name.
So what's the attraction of ageing dinosaurs from the days when BSA was the largest manufacturer of motorcycles in the world? What gems or horrors await the hardy souls daring, or foolish, enough to venture into this Belstaff wearing world? I was going to say Barbour wearing but that firm's excellent jackets have been usurped by chinless yuppies in Suzuki jeeps accompanied by their elegant ladies and smart dogs (sometimes it's hard to tell them apart).
The range had five models, all in a state of constant development (no, that wasn't a joke). There was the M20, a 500cc side-valve sluggard mostly issued to squaddies in the war. With the opposition on BMW's it's a wonder we won! Then the red hot technology of Birmingham developed the M21, a 600cc side-valve engine with an insatiable appetite for exhaust valves if pushed to dizzy levels (over 50mph). Most were attached to sidecars where the lack of top end performance helped to keep their intrepid rider in one piece. If you broke down, the AA came to the rescue on a similar mount.
Side-valves were cheap to produce but limited in potential, so progress couldn't be halted and overhead valves arrived at BSA with the B31 and B33 350 and 500cc singles. For solo riding they were, and are, the best of the bunch. Back in the late forties and early fifties they started out with rigid frames, progressed to plunger back ends and reached the modern era with swinging arms in 1954. The final post 1958 models even abandoned magnetos for alternators and coil ignition - whether or not this was progress is somewhat doubtful. It just meant that instead of being an optional extra, added to impress policemen, batteries became essential.
My present bike's a 1950 B31 which, as those who've been paying attention will know, is an overhead valve 350 single equipped with a sprung saddle and a rigid frame. It looks and rides like something from a different world. Handling, on smooth roads at least, is surprisingly good! No flexing swinging arm with clapped out bushes or complex suspension linkages to pick up grime and grit; in fact, no swinging arm at all.
Of course, your spine has to take a while to adapt to rough roads and potholes. It's all down to what kind of machine you're used to. I admit, that the B31 could come as a great shock to the system to a British bike virgin. It's only when you hit bumps and potholes halfway around a bend and the rear end starts skipping across the road, that you begin to understand why rear suspension quickly took over the world when it was introduced. Under normal conditions comfort is actually better than you'd expect, thanks to the well sprung seat. Admittedly, an old saddle will have you wobbling about all over the place.
Seat height is only 30 inches so you don't have to be tall, although life for a pillion's close to hell, but that is someone else's problem. The peg/bar relationship could teach some modern cycles a lesson, although it is a slow bike and I've fitted a protective half fairing in white to confuse car drivers. They hear and feel the single cylinder thuds before they see the bike as a flash of white which could to their panicked minds be a plod motorcycle.
The brakes look pretty minimal, half width SLS items, but in the context of slow, sensible riding they are able to cope with the stopping of the 350lb bike. Forget all the stories about old British bikes having poor brakes, if they don't work properly, something is probably wrong with them - poorly adjusted or worn out shoes, seized up filthy cables or oval drums are the most likely culprits.
Starting is no problem once you know how. Tickle the carb to flood it a little if it's cold, retard the ignition, use the valve-lifter to ease the piston past compression, release the valve-lifter and jump on the kickstart. All things being equal, it’ll start first time. The ignition system's totally self contained. A magneto feeds the spark plug, that will work if the battery's dead or not even fitted! The brushes do wear out eventually but it's easy to service; the same technology used to be employed in aeroplanes and it was only replaced because the alternator and coil system was cheaper. Of course, with any big single it's possible to muck up the kick and be thrown through the air; a useful anti-theft device!
Fuel consumption is excellent, 70mpg easy to achieve and more than 80mpg possible with a little care on the throttle. It will break the 70mph limit but only just. Top speed by modern standards is a joke. Still, at least it's impossible to get a speeding fine! In any case, no-one buys a forty year old 350 to go fast on.
Forget, also, tales of unreliability. Used as intended, that is for plonking along at 50mph, with the occasional short, mind bending, burst to the dizzy mid 60's, the machine will probably go on for another forty years. It was only when the faster Japanese machinery started to arrive and British manufacturers responded by trying to squeeze extra power from obsolete designs that reliability went out of the window.
Bikes of the fifties and early sixties were, and are, very reliable. That must've been part of the problem. Once Joe Public had bought one he probably wouldn't need to replace it for twenty years. If anything does go wrong, spares, for this BSA at least, are plentiful and cheap. Try getting a piston complete with rings and gudgeon pin for your Kwackazappy for £25.
Getting MOT's is fun, too. You have to find the right garage. I was once failed by a tester who said he couldn't pass the rear shocks because he couldn't find them. With a sympathetic tester I just spend 30 minutes chatting about bikes and after one glance I'm away for another year. There's nothing much to test, anyway - no swinging arm bushes, rear shocks, indicators, brake light.....
Still not sold on the idea of an old BSA? Take one out in the country on B roads or smaller, plonk along in the sunshine, watching old codgers' faces light up as you thump by and stop at a pub to be greeted by half of the locals with, 'I had one of them when I was a lad.' They still turn up hidden in the back of barns and garages if you don't want to pay Classic Bike prices.
Alan Frost
Sometimes life takes a curious twist and goes down unexpected avenues. Back in '89 I'd crashed my CB900 four into the back of a car at a closing speed of about 50mph. I'd blinked and what had been an empty road suddenly had a cage tottering along. Blind, frozen panic was my far from useful reaction. I could quite easily have been killed but apart from shock and some bruises I'd escaped with my full leathers being reduced to rags.
Both bike and car were complete, utter write-offs, although the fusing of the two could, to my mind, have made a neat bit of modern sculpture. The aged car driver was led away babbling incoherently whilst I almost came to blows with the ambulance men over my refusal to go to hospital. I was still in a state of shocked confusion, some five days later, when I bought a 1967 BSA B44, an 441cc OHV thumper.
'What the f..k didya buy one of 'em for, you daft bugger,' was the general consensus of opinion amongst my so-called mates. I just shrugged my shoulders and looked more gormless than usual. The usual tirade of abuse followed when the B44 refused to start whenever an audience assembled to view the fearsome sight. The noise out of the open megaphone and a chassis that jumped about like it wanted to take up rock and roll promised performance on a level with a turbo-charged Kawasaki Z1, an illusion that was shattered the first time the engine was used in anger.
The B44 had its roots in a trail bike, what I think were then known as scramblers, its power was of the soft, though far from svelte, nature made for going up mountains over muddy terrain. The street version ran taller gearing and different cams, a combination that all but eradicated any chance of wheelies - it was possible with a lot of clutch abuse but that was more likely to lead to a chaincase full of clutch bits than true highway happiness.
I was quite dismayed to have to really abuse the throttle and gearbox just to keep urchins on 250 Superdreams in sight! The effect of revving the bike through the gears was to turn the whole landscape blurred as the vibes wrecked my sight and left my extremities shaking like I was having a fit. No, no, no. The B44 has to be ridden in the context of a lazy, laid back thumper when it begins to make some sense.
With a weight of around 300lbs, about 30 horses and the compact dimensions of a Japanese 125, the BSA was easy to hurl around town and country roads, kept in third gear below 45mph there was no need to slip the clutch or chance a broken left hand by excess abuse of the lever. Once I became used to having the gearchange on the wrong side, the box turned out to be quite slick except when a couple of hours' town riding on hot days overheated the engine. Then it rattled, locked up or turned out a plenitude of false neutrals. Clutch drag would also rear its ugly head with consequent stalled motors at junctions.
Starting a hot engine required judicious throttle positioning and a brave kick that often snapped back with ankle breaking intensity. Okay if you're ready for it and wearing heavy-duty boots but very nasty when an innocent in trainers tries a half-hearted prod. Cold starting needed a flooded Amal and about four kicks before the engine made encouraging noises if not fired. Several times physical exertion, in the form of a bump-start, was necessary.
The lack of dragging disc brakes and low mass made this easier than expected. The combination of TLS front and SLS rear drums, given its 90mph top speed, was more than adequate for the kind of limited riding that the vibrating motor permitted. A useful bonus was that the brake shoes didn't seem to wear at all (as well as being brilliant in the wet), although shagged rear chains in less than 6000 miles more than made up for such frugality.
Similarly, heavy oil consumption more than made up for reasonable fuel economy. About 75mpp and 65mpg. A lot of that oil leaked out of the engine joints even when the bolts were tightened down with such intensity that they threatened to pull their threads out......they kept coming loose, needing attention every few days! Some kind soul had fitted electronic ignition, so maintenance was merely adjusting the two valves every 1250 miles and playing with the single carb's idle settings whenever I felt really keen.
Despite forcefully expressed doubts by my mates, the B44 ran rather reliably on the road, able to do 250 miles in one sitting before I had to go over all the loose bolts. The intensity of the vibes rose exponentially once over 5000 revs but relatively tall gearing made for a relaxed 70 to 75mph, with a gentle thrumming running through the machine that was more invigorating than tiring. First time riders did express doubts as to its mechanical integrity but they had been spoilt by a surfeit of sophisticated Japanese machines and wouldn't recognize true character even if it hit them between the eyes.
I managed to extract 22000 miles in three years of joyous riding before the engine began to complain. I think it rather took exception to the time I ran it along at 85mph for half an hour when I'd strayed on to what was supposed to be a motorway but judging by the general traffic speed was some kind of race track. Everything started to wear out all at once - bore and piston, valves, chain primary drive and even the big-end as well as a gearbox that decided once it was in third gear it didn't want to come out again.
The chassis was fine, generally competent with no hidden nastiness and would probably have taken rather more speed than the motor was capable of producing. I liked its looks as well, with the tank in fern green and black, the outline enhancing the butchness of the motor.
Now, B44 engine spares are not exactly abundant or cheap (many CCM bits can be used) but spurred on by all the tales of self-destruction I'd read and heard, I'd managed to pick up some major components over the years at reasonable prices. The rebuild was just a matter of fitting these components into the disassembled motor and hoping that all the tolerances went the right way - some of parts were built to such a low engineering standard that the tolerance build-up could leave massive clearances in moving parts, with subsequent poor performance and excessive vibes.
The gearbox selectors proved rather elusive but turned up just as I was becoming desperate. An engine with practically new components was finally assembled, polished and sealed with the latest in liquid gasket technology. When it started on the third kick I knew I'd done a good job. 2000 miles of running in followed, which turned up no major problems and revealed a motor significantly smoother and faster. The screws didn't come loose any more and I could cruise at 75 to 80mph, with a 95 to 100mph top speed. Oil leaks were minimal!
If this was how they came out of the factory then BSA had a winner on their hands that they were silly not to develop. During the next two years I did 16000 miles without major incident. Then, just a week ago, I smashed into a car again. This time it certainly wasn't my fault as the auto had sped out of a side street at warp speed, driven by a juvenile who could barely see over the wheel. The police were on his tail and helped me up off the ground after I'd summersaulted over the car and down the road a few times. Car and bike were once again coalesced and I refused to go to hospital despite what felt like a broken neck. Two accidents in five years isn't bad going, I suppose, but I think it's about time I bought myself a nice safe tin box. Maybe!
AG