No-one else makes vertical twins the British way. Yamaha, perhaps, came closest with their XS650 and both Laverda and Benelli gave the dice a throw, but all three big twins lost the point with their excess of mass. The Japanese make modern vertical twins but don't put much effort into them, the GPZ500S and TDM850 the only ones that come close to being interesting. But British twins are as intrinsic to this country as some resolute old dowager, and just as firm in their constitution.
Take two big flywheels, a couple of puny bearings, hang off a pair of con-rods and the biggest pistons you can get away with. Keep everything as simple and cheap as possible - pushrods, chain primary drive and a minimal amount of metal in every possible component. British designers grew up on postwar days of steel rationing and never quite got over the shock!
The result of these machinations, a 650cc twin weighing 350-400lbs, capable of putting 110mph on the clock and flying through the bends. Some were better than others. Norton had the best frame in their Featherbed design. Triumph had the strongest and least vibratory engine. BSA's handled better than Triumphs, were less vibratory than Nortons. Royal Enfield were more advanced than anyone but that didn't stop them gushing oil. AJS and Ariel never really made the grade but time has been kind to their status, rareness working wonders on their credibility. In fact, most of these bikes are so old and so modified along the way that it's impossible to be definitive about which is currently the best engine available. Even standard looking bikes can hide much modified motors.
Some things never change. Triumph Speed Twins, for instance, however well put together the chassis, however new the bearings and however modded the suspension, still behave like buckling bronco's in tight, bumpy bends at anything remotely approaching a decent turn of speed. Featherbed 650 Nortons, even with upgraded, balanced cranks, rubber belt primary drives and meticulously assembled engines still vibrate like primeval old dogs above 6000 revs. And BSA engines turn as finicky as a three-legged dog if you tune them beyond certain limits.
On the other hand, there are any number of well put together, upgraded British twins out there that are very fine riding devices. As long as you stay within the definition of sane motorcycling - rarely going above 90mph, with an 80mph maximum cruising speed; gentle on the controls at all times. Out of that you get plenty of cheap kicks, reasonable reliability and a bike that goes up in value the longer you own it. This is the kind of trip you want to get into if your licence is nearly dead and you've had your fill of Japanese hyperbike thrills.
In the beginning, more or less, there was the Triumph 500 5T of 1946 vintage, aka the Speed Twin. The infamous Sprung Hub back end gave this bike the characteristics of riding a camel whilst the engine vibrated furiously away. Its adherents main claim for validity, except for its external lines, are that all the elements of motorcycling are rendered miraculously direct - that is you feel every road bump, and every ounce of effort in turning petrol into forward motion. Those owners with any teeth left have usually ground them down to the stumps! These are serious classic bikes - the definitive engineering for a whole breed of subsequent Triumphs, not to mention a vast array of imitators; therefore seriously expensive. Two and a half thousand notes might just get you in the game for one of the later examples.
Look for oil tightness, relative smoothness below five grand (you'll need to try a few examples to see what I mean), lack of exhaust fumes plus a quiet engine. Well built examples don't leak much oil and have a very gentle tickover. Hopefully, you'll find one with all the usual engine upgrades, plus some modern drum brakes!
The 350cc version's so mild as to be dangerous on modern roads but some people revel in the relative lack of vibration. The 650cc 6T likes to break chassis parts when revved out fully, but few owners subject their pride and joy's to such outlandish abuse. All of these old Triumphs are limited by a lack of practicality - unless you're the kind of old codger who enjoys roadside intervals to fix minor problems (and many old Brit riders are!) - and their classic bike status.
Another curious old Triumph of that era, the antique sidevalve TRW. This was the mother of all old sluggers; hardly any power, mediocre frugality and some strange handling on anything other than smooth roads. What it had going for it was an extreme simplicity and a certain ruggedness, the kind of bike that could be bodged around the clock a few times. Of course, time has also been kind to its looks and it's more likely to stop traffic than some modern hyperbike. You can still find something useful, if sensibly modded, for around the grand mark.
Move on a few years, some more interesting Triumphs emerge. Though they didn't really fix the frame until the mid-sixties, towards the end of the fifties something like a 500cc T100 Tiger had a useful blend of power, practicality and just plain good old kicks. Arguably, the singled carb 500cc Triumph twin is the best of the bunch. For sure, its 30 horses lost out to the more powerful 650's but practical cruising speeds were actually very similar due to the bigger bike's excessive generation of vibes. Well rebuilt, at around the three thousand note mark they offer a lot that is best about old style British motorcycle riding.
The purists still deride the change from pre-unit to unit construction, arguments for and against on both sides. What's far more important, these days, is the actual state of the motor and the unit construction bikes certainly have a better reputation for longevity when used in anger.
The most infamous of this bunch, the T120 Bonneville, though it had a couple of years in pre-unit construction format before the real thing emerged in the early sixties. A marvellous line in style, enough power to put 120mph on the clock on a good day and the best reliability of this era of British twins. Vibratory, leaking oil and prone to bearing and valve-gear failure when used to the full, most of these hassles sorted with a bit of modern re-engineering.
A good Bonnie, as opposed to a bad one, is an almost lyrical experience - once you get used to the vibration and queasy handling on the early models. I'd go for a 1967/8 model, that had the chassis as well sorted as it was going to get, had reasonable brakes and suspension, as well as being the toughest of the bunch. Dealers want five grand for such a bike, but the private market will turn up a marvellous one for 3500-4000 quid.
As with many Triumph motors, they can keep running with an awful lot of internal wear. It's not unknown for someone to whip the head off when investigating a minor problem to find out the whole engine's in need of replacement. The good engines are discernible in their relative lack of vibration, noise and oil leaks but you have to be a bit of an expert to suss the good from the bad.
Another nice sample of Triumph engineering from the sixties, the T100SS, had all the qualities of the earlier 500cc Tigers, better build quality, slightly more power and better economy. In the kind of typical riding that British bikes are subjected to, the T100SS is more useful than the bigger twins and a generally fine tool. Though prices aren't bargain basement, it's still possible to pick up something useful for around the two grand mark.
One of Triumph's greatest mistakes was to push their venerable vertical engine to 750cc; at least they didn't tweak the power in the same way that Norton did. Prices of the 750's have surged ahead over the last year for no sane reason, nostalgia being a strange and wonderful thing. Added to its extra capacity, the factory often churned out Friday afternoon specials, poorly fitted if not engineered components adding to the chaos.
Most of the nastiness should've been sorted by now, plenty have been completely re-engineered using better quality modern materials. Vibration is impossible to eradicate, though, especially on the twin carb engines - so that makes a late T140 Tiger the best bet as it also had the lowered saddle height version of the oil-in-the-frame chassis (which was also less susceptible to cracking up). The rougher ones go for under two grand.
Nortons never quite matched the ease of style of the Triumphs. The Wideline Featherbed frame limited the way the tank and saddle could be moulded into an object of desire, though the lines of the engine were arguably more attractive. The motor that was to go on to infamy in the Commando series, had its roots in the Model 7, something of a vintage relic left over from the war that in no way presages the Featherbed's excellence of handling. View the Model 7 as a decent enough old plodder and it wasn't half bad but in no way up to dealing with postwar 500cc Triumphs.
Norton' solution, in 1952, was a brand new rolling chassis, the infamous Wideline Featherbed frame at its centre, but it also benefited from Norton's race track success with regards to suspension and steering geometry. The 88 Dominator admittedly suffered from vibration, even at such a minimal capacity, so much so that it could crack up early model frames.
It wasn't until the 1960 Norton 88SS Dominator that the design really peaked, blending a 36hp 500cc mill with the Slimline chassis, Roadholder forks and the best styling that the Featherbed series was to attain. A much more manly device than the Triumph Daytona, it could crack the ton without much effort and steered with unheard of precision and fidelity that if you overlook the lack of suspension travel is on the pace with the more mundane Jap middleweights of the nineties. Three grand up for anything remotely decent, but at that price it should have all the engine mod's going, making it even better than stock.
Equally of note, the 650SS took the Norton engine as far as it really ever wanted to go, could keep pace with the Bonnevilles of the day and was almost the perfect embodiment of the British twin... save for the way it could vibrate madly when used harshly. An extra grand's needed over the 500 and it may not be money well spent but there are plenty of engines that have been totally sorted.
It's best to avoid the 750 Atlas and probably all 750 Commandos. I say probably because there's the odd one that has been detuned and upgraded that makes a remarkably useful road tool. You have to be pretty quick off the mark to find them, though. No, better to go for the 850's, in as mildest a form as you can find, the later the better - post '75 Mark 3's in particular, although many engines have been upgraded to superior spec. Three to four grand, please.
BSA twins were somewhere between the Nortons and Triumphs, eventually becoming passe when the latter actually managed to make their motorcycles handle in a reasonable manner. The pre-unit series the defining BSA's, the 650cc A10 the bike of particular note. Its major weak spot, puny main bearings, all but eradicated by the pervasiveness of the SRM roller bearing conversion.
Most A10 motors are now well sorted, smoother than the Triumphs but something of a plodder rather than anything to set the blood aglow. Try to avoid the early ones, the chassis not up to much - the duplex frame version with twin shocks is the only model up to the nastiness of modern roads and even then it isn't safe at speed unless sporting the TLS front wheel conversion. There are still usable examples on the private market available for less than two grand.
The A7 isn't a bad motorcycle, just a tediously slow one. Unlike the A10, the better version's the A7SS, which at least had enough blood and guts to stop the rider falling asleep, more of a revver than the harsher 650. It's a better buy than the later A50, which had to carry too much mass, although it could last for a long time. One of the milder unit construction A65's is closer to the mark, something like a Thunderbolt with the obligatory SRM crank conversion. Plenty of well sorted examples of all three models for less than two grand, making them something of a bargain buy in British vertical twin circles.
Whilst Triumph, Norton and BSA were dominating the sales charts and the roads, Royal Enfield were trying to bring some relatively modern engineering to the genre, though they were never to master the art of correct engine breather placement, often derisively described as Royal Oilfields. Even in 1950, their 500 twin had the gearbox bolted to the back of the engine and the sump cast into the bottom of the motor (though it still circulated oil as if it was a dry-sump system). The 500 peaked in the Meteor Minor of the early sixties, arguably a better bike than the more main-line British twins but, these days, those twins have largely been upgraded and have a reasonable spares situation. No such effort has been put into the Enfields.
The best buy amongst the Enfield camp is one of the last Series 2 mills which ended up in the excellent Rickman frame. Here you have an almost modern British vertical twin, a glimpse at how the breed might have developed if there had been enough money around to exploit the talents of British engineers. The Series 2, unique amongst British twins, actually had a wet-sump engine, hefty main bearings and a dynamically balanced crank. That added up to a mix of heavy power (not quite up to the standards of the wilder Commando's but it could take any Bonnie), almost as usable as an 850 Commando on the motorway (beyond 85mph vibes began to go heavy) and sturdy handling that bettered the rest of the Brit's in stability, the only limitation from its mass when swinging through the tighter bends.
This is a serious motorcycle, then, likely to appreciate in price greatly as rareness sets in. The spares situation isn't desperate but it's nowhere near as easy as in the mainstream of Brit twins. As there are no serious engine defects there's not much re-engineering needed, the main problem from fitment of shoddy parts - if you want to use this as a proper motorcycle, bear in mind that the build quality is variable. It's an easy way to write off four thousand notes if you don't know what you're doing.
Whereas most Enfields have some interesting engineering on offer, neither Ariel, AJS nor Matchless managed to rise above the middle ground of British technology. In all of these cases, look for something mild in nature, well preserved and basically stock, though obviously the more new engine components the better. If you join the relevant owner's club, the spares situation is reasonable for engine parts but sometimes difficult for the metalwork. Which at least shows they have their priorities right!
AJS and Matchless were basically the same models with different badges, eventually being taken over by Norton. Ariel ended up as part of BSA, used the A10 engine in later models. There are still some models of each make with motors running in a pretty dire state, and they keep clacking away to the last possible moment, which can prove expensive. It's more a case of avoiding the Ajay Model 33 (that Atlas mill!) and tracking down something with a few spare bikes thrown in as part of the deal. They can be relatively cheap and sensible ways into the British bike scene.
So there you go, loads of possibilities, lots of potential and some bargains. There's also a huge social scene, great friends to be made and lots of people who'll go out of their way to help you out. Can't be bad.
Johnny Malone