BSA made more than 500,000 Bantams over the years - yes, wasn't the British motorcycle industry big not so many years ago. Compare that to all the cries of joy when the new Triumph company shifts 5000 bikes in a year. Not that you'd believe the past achievements from the number of Bantams still left on the road, a crying shame to my way of thinking.
In recent years, except for my hard working D175, the only one I've see is an early 125 version with rigid rear end and L-plates! The fellow had the audacity to fit long forks and paint it bright pink!
I dare say there's an owners' club somewhere but the last time I joined an organisation the Boy Scouts still stood for youth and innocence. Days when men knew what their right foot was for and anyone riding a Japanese bike was laughed at, they looked even funnier than Mods in parka's on scooters. I never had the chance to beat up the Mods and now two-wheelers are so scarce that we all have to be friendly.
By the time my 1969 D175 was manufactured BSA had put in 20 years worth of development from the original D1, itself closely related to the German DKW design. Similar engines were to turn up in the Eastern block, the design relatively easy to build and assemble, but none done as well as the Bantam.
Power was mild for a two stroke single of 175cc, 13 horses at 6000 revs, but many were the tuning options - often a quick way to ruin the reliability. The D175 benefited from a heftier crankshaft, better designed crankcases and a slightly lower compression ratio than other models at 9.5:1. The four speed transmission was a bit of a throwback to earlier days.
I have tried a high compression piston and running without the baffles whilst advancing the ignition. RD fans might wax lyrical about the resulting noise and laugh derisively at the mere 85mph top speed that resulted, but the engine became very finicky at lower revs. It was also possible, mandatory amongst youngsters, to take a file to the ports. Unless done with the kind of finesse and precision possessed only by the top tuners the piston could measure its life in hundreds rather than thousands of miles.
Kids will be kids, and many were the engines destroyed before their time. I can recall one youngster with the Bushman version of the Bantam, what could loosely be described as the leading trail bike of the day. He was desperate for more power, spent days taking the engine down and fitting go-faster bits. By the time he'd finished with the barrel there was more port than bore surface.
On the first day, without even bothering to run the components in, he speed tested the Bushman on a newly opened section of motorway. He reckoned he did 90mph before the engine seized the first time. After half an hour's cooling she freed and started up. The second seizure was at 50mph, the repeated violence on the transmission causing the clutch and gearbox to break up.
The locked back wheel threw him down the hard shoulder and left the Bantam to be flattened by a white Ford Anglia. I know it was white because I spent hours dismembering its bonnet from what little was left of the Bushman. The rider escaped with minor bruises and cuts, was soon repeating his hard earned experience on a Suzuki T200. A machine that repeated the Bantam's seizure at even higher speeds and with a similar result. This time I didn't offer to buy the bits off him.
The weakest part of strokers of this era was the simple lubrication system but as long as the throttle was restrained the piston and small-end refrained from seizure. I was always reassured by the haze of burnt oil, at least I knew some oil was getting through to the engine.
I preferred to keep my engine stock, both for longevity and ease of running. I didn't rate the transmission very highly. A high state of tune resulted in much cog swapping and clutch abuse, especially in town. That was only okay if you didn't mind a chaincase full of broken clutch plates and primary chain rollers.
Invariably, high mileages of over 20,000 would wear out most of the crank's bearings as well as the piston and bore. I did manage 35000 miles of mild riding out of one engine, with a decoke and new points every 5000 miles. A good helicoil kit's essential on machines of this mileage, as threads do tend to strip. The bike being more of a commuter than the preserve of enthusiasts, resulted in many being dumped after a few years of life when they failed. Hence the rareness of the bikes.
Who remembers all those Post Office Bantams? Me, I've got a couple in trillions of bits at the back of my garage. My brother actually worked for the PO for a while and had the undoubted privilege of riding around on a Bantam all day long. I tried to get a job there, too, but was told I had the wrong kind of attitude. All I said was that I wanted the job to ride around on bikes all day and, of course, for the money. My brother reckoned I was well off out of it as the bike was very tiring to ride all day, not having very comfortable suspension and cheap tyres that turned wet roads into ice-rinks.
The chassis was good enough to house the Tiger Cub's engine in the last days of that model's reign. Suspension was inspired by that fitted to bigger BSA's, actually being damped and tautly sprung, a rarity amongst both Japanese and British commuters of that time. Most Japs had such naff suspension that they waggled like irate ducks when chucked through the curves. In the cut and thrust of the bends I could take them easily despite their speed advantage.
The frame's more than adequate for the 75mph top speed. Comfort was just acceptable on bumpy modern roads as I'd had the seat filled with high density foam and upholstered a couple of years ago. The suspension's been rebuilt a couple of times but is basically stock. I was bought up on this kind of bike and don't like the remoteness from the road of modern machines - I will readily admit they have a much more sophisticated ride, but who cares, the bike still gets mewhere I'm going. The years have toughened up my body. Mileage now stands at 86000, with three engine rebuilds consisting of new crank bearings, pistons and
barrels, plus the transmission. I was lucky to buy the bike in 1975 when they cost next to nothing, buying up lots of broken engines for a few quid at a time. Rebuilds are not expensive, only new gaskets needed as I have enough engine parts to open a shop.
The D175 weighs only a few pounds over 200lbs, its taut, lithe chassis great fun around town or out in the country. As long as I didn't have any trouble with the electrics, which always appeared a bit dodgy. On a rare day, the alternator might pump out 60 watts but little of this power found its way to the lights. The coil ignition gobbled up whatever power came its way, leaving a murky glow that might just attract the more desperate moths. I have got the ignition working directly off the alternator via a big capacitor, so it doesn't really matter about the rest of it.
These days a good Bantam costs about five hundred quid which seems like jolly good value from where I'm sitting. As well as being a potential classic they are still useful commuters, if you can take the lack of electrics, brakes and suspension travel, enjoy the sure-footedness and low running costs. As a first British bike for a learner the 125 version would be highly entertaining and have as much pose value as a Cagiva Mito.