It has to be said that BSA pleased hardly anyone when they named their last big single the Gold Star. I was pretty young at the time of this sad event, but my youthful ears were assailed by the sound of grinding teeth from those of my acquaintance who were fans of the long-gone DBD, etc. pre-unit bangers. I didn’t mind what BSA called the ultimate C15 derivative; I just thought it looked and sounded wonderful. I even liked the ‘lozenge’ silencer...

But oddly enough, I had somehow managed to avoid riding a B50 for the whole of the twenty years since they were current. Not sure quite how it happened, but there we are — must be fate! I covered a lot of miles in the mid 70s on a Blazer SS, the 250cc Triumph version of BSA’s oil-in-frame single, and apart from its in-ability to retain its indicators on prolonged M-way haulage my memories of it are completely benign. The opportunity to borrow a big bad B50 for a short spin was welcome, therefore.

A little history for you. The B50 SS Gold Star, which was apparently its catalogue designation, was unveiled in 1971, and limped along in production until 1973. Author Steve Wilson (who actually owned one for quite a while when both he and the bicycle were in their youth) reckons that ‘around 5700’ B50s were built in all, which makes it slightly surprising that so few are seen about today — in fact, I don’t recall seeing many about when they were current, either. Which is unfortunate, because they make good traffic bikes; if not serious highway haulers.

Perhaps the reason for their scarcity, then as now, is because so many were exported. Their styling, which to my mind still ranks as one of BSA Umberslade Hall’s better efforts, was intended for our Stateside cousins, after all, and the bikes I rode had both been recently repatriated.

Anyway, the single cylinder ohv pushrod design features almost square bore and stroke dimensions of 89 x 90mm, to give a capacity of 499cc. The all-alloy motor whacked out a gutsy 34bhp (the B50MX version claimed 38) which had no trouble at all in propelling the 310lb's of bicycle along at quite respectable rates for the time. In fact, as I was lucky enough to find myself on a far more recent XT500 Yamaha only a couple of days after sampling the B50, a thumbnail comparison suggests that the Beesa was the quicker of the two, despite its lower number of ratios and simple pushrods. I digress. Useable top speed was really about 80mph (and my old Blazer could cruise happily—well, mechanically happily, anyway — at 70, on a lot less power), although fitting higher gearing to the 500 apparently imbues it with ton-plus performance. Me thinks you’d need flat bars and a set of the optional gritted teeth!

The chassis for this rather clattery powerhouse was in line with BSA’s revamped twins of the time in that it carried its lube (all four pints of it) in its frame tubes. Bafflingly, although the 250s had a cartridge oil filter as well as the gauze strainer affair which screws into the bottom of the front down tube, the more stressed 500 does not. Ho hum. The front forks were the ‘slimline’ type which soldiered on with the 750 Bonnie until its demise and worked quite excellently, as did the conical hub brakes. I’ve never under stood why folk moan about those stoppers, they have always seemed OK to me, and contemporary road testers reported that they stopped the bike in 29ft from 30mph, which isn't bad.

A nice touch, and one which could have usefully been carried over to the twins, was the simple and accurate method of adjusting the final drive chain by using eccentrics at the swinging arm pivot rather than those horrid cheap screw-adjuster efforts at the ends of the arm.

The Street Scrambler (for that is what the ‘SS’ stands for) in also universally criticised for its light grey (Dove Grey, in fact) frame. People whinge on about how impractical it is for a frame to be grey. Yawn; when it’s clean it looks neat, in my view, and when dirty it just looks dirty. Whatever your views on its looks, the single downtube oil-bearing frame certainly handles well. And so it should, being developed from the chassis which John Banks scrambled so successfully in the mid-Sixties. The roadster engine’s poke doesn’t bother it at all, and you can bash about the blacktop with the gay abandon which is familiar to all who ride the large capacity Japanese trail bikes these days.

That was the problem, really: BSA were being perhaps a little adventurous in their marketing of their last single (which is perhaps odd when you consider how often they are accused for being pedestrian in their outlook). Perhaps British riders weren’t ready for the evolution of the dull-looking B44 into this spindly quasi trailster. Perhaps they really did prefer ‘sensible’ silencers and voluminous mud guarding. OK. So why did they rush out and buy Hondas?

BSA’s approach to their bikes’ electrical system was fairly novel, too. Not only did they stick a capacitor into the circuit so that the B50 could be ridden with its headlamp and battery removed (for those who really did want to ride off-road), but they developed a neat ‘black box’ electrical pack for the ignition coils, Zener diode and rectifier, and hung it under the nose of the petrol tank, where it could be quickly and easy serviced or removed. A far neater approach that scattering electrical bits at the ends of lengthy wires all over the bike.

Although the 500 engine looks just like a fat version of the 250, inside it was quite a bit different. Where the 250 had a plain bearing for a big end, the bigger banger had a needle roller big end assembly, which ran on three main bearings. Built to be robust, indeed. The handlebar switches were those familiar Lucas items which are great when you’ve got used to them, I never liked them, and have got fed up with pushing the wrong ones every time I’ve come across them. At night, when I wish to dip the headlamp, I get cross when the bike indicates left instead; when I want to toot the horn at an errant pedestrian, the engine cutting out is not a preferred option!

Riding

It would be wrong to suggest that I spent much time in the saddle of either of the two bikes I was offered. I didn’t, enjoying a sunny trundle through some sleepy Cheshire countryside and a couple of healthy blasts just to let the old warrior clear its throat a little. I was hoping to have more time on the bike, but once Gavin from Greenlooms got out onto the fields with it we couldn’t get him back! He just kept racing about in clouds of dust and a surprising lack of sound and fury. It’s the noise or rather the lack of it which is one of my abiding memories of the B50. Big singles especially quick big singles are supposed to sound rorty! What’s the point in cutting a dash on a British banger if you sound like Corporal Sensible on a Honda XL250? At low revs, the greatest noise is piston slap from the alloy barrel, coupled with an unhealthy pinking at wide throttle openings; at higher (50+) speeds, you are too distracted by the effort of hanging on to notice the exhaust at all. It really is very quiet for a Seventies motorcycle.

But if the B50 was quiet, then it certainly wasn’t smooth. Oh no. At low speeds you could feel every power stroke just like my old AJS and when cruising speeds were attained, I was reminded of the reasons why my old Blazer used to shed its indicators! But never mind.

The ‘conical hub’ brakes were pretty sharp, especially the back one, and the test bike’s (original 1971-looking!) Dunlop K7Os were sure-footed enough on the tarmac. It is a very nimble bike, with very quick steering - street scrambler is a pretty accurate description.

If the B50 had one glaring fault, it is its reluctance to start. This one was just awkward. Once its battery was charged and its plug clean, it would sometimes start straight away. Other times... well, let’s just say that it wouldn’t.

An acquaintance once said that there were two kinds of B5O: those that won’t start, and those that break cranks. I hope he was joking!

In the volume II of his series of books covering the British post-war motorcycle industry, Steve Wilson describes the B50 as ‘an instant rejuvenator’. I can’t better that, and I can only agree. If you want a short-hauler which will put a twinkle back where it belongs, this could be the one.

Prices

You don’t see that many B5Os offered for sale these days; there are certainly nothing like as many around as there are the earlier singles and late twins, for example.

When you do see them, they are offered at prices between £1000 and about £1650 (equivelant 2000 prices between £1600 and £2800), which seems about right. Spares supply is reasonable, as is insurance, and the BSA Owners Club is reputed to be a good one.