Bultaco Motorcycles - CLASSICS REMEMBERED

Big ideas don't always come from big outfits. Bultaco's idea was to power a small, light motorcycle with the two-stroke engine that was rapidly gaining muscle in the late 1950s. In 1956 the Spanish make Montesa pushed aside all but one of the usual parade of high-revving DOHC Italian 125 four-strokes at the Isle of Man TT; Carlo Ubbiali won on an MV, but 2nd, 3rd, and 4th were Montesa single-cylinder two-strokes.

Something new was happening. Everyone “knew” two-stroke motorcycles were cost-cutting, smoking horrors like DKW’s four horsepower RT125, but here were Spanish-made two-strokes, not only finishing the grueling 97-mile 125 TT, but reaching the podium.

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In 1958 Montesa management withdrew from racing against the wishes of engineer/partner F.X. “Paco” Bulto. By 1959 he was producing a new brand – Bultaco – embodying the same concept; a surprisingly powerful two-stroke engine in a comparably light chassis. Although there were plenty of four-stroke machines as powerful, none was nearly as light.

Bultaco's 'Tralla 101' was a simple road bike much as DKW's RT had been, but it made three times the power. Its 125-cc engine of 51.5 x 60-mm bore & stroke made 12-hp in the simplest way – with a single exhaust port, a single piston-controlled intake port, and two Schnuerle-style transfer ports. The piston had a nearly flat crown of minimum surface area – not the gross, heat-gathering "deflector" piston found in so many two-strokes of that time. Recent scholarship suggests that Sr. Bulto, on buying trips for such specialties as Mahle pistons and INA bearings, somehow arranged to meet with Walter Kaaden of MZ – the East German engineer who was in process of harmonizing all two-stroke technologies into a functioning whole.

Bultacos were simple, air-cooled, with enclosed chain primary drive and (initially) 4-speed gearboxes. In the mid-1960s while servicing a Bultaco crank, I read through all the service bulletins on hand. One quite seriously suggested that the common problem of oil leakage through porous crankcase castings could best be solved by complete disassembly, followed by ‘lightly peening the entire inner surface of the case with a small hammer.’ For those accustomed to the quality control and rapid technical evolution of Japanese brands, Bultacos were a little rough.

Never mind. Bultaco had brought outstanding power-to-weight ratio to light motorcycles, bettering the performance of many respected four-strokes. In British road racing, Honda's semi-exotic and high-revving DOHC CR93 twin had ruled the 125 class – until Bultaco's TSS 125 made the scene. Barry Sheene's father, known as 'Franko', became 'tuner-at-large' for the growing population of TSS Bultacos in British paddocks.

The 125 was followed by a 200 in 1962 and a 250 in 1963. Soon came water cooling. As simple as they were, these were race bikes riders could afford, so every spring before the pre-season Alicante event, British riders would stop in Barcelona to exchange last year’s 125 and 250 for this year’s. Because of their two-stroke torque and light weight, Bultacos did especially well on short courses that favored acceleration. Case in point; In 1969 New Zealand GP veteran Ginger Molloy was 3rd in 500 at Jarama (near Madrid) – on a 360 version of Bultaco’s simple single. Who won that day? Agostini, on an MV Triple.

For Americans, Bultaco meant light, manageable off-roaders – enduros, short-trackers, motocrossers. In all these areas, four-strokes now became also-rans or worse as Bultacos and other European two-strokes "put 'em on the trailer". Naturally it wasn't long before Japan's eagle-eyed and trend-seeking product planners saw in Bultaco's in-group popularity the leading edge of a revolution. A flood of light Japanese two-strokes followed (beginning with Yamaha's DT-1), leaving Bultaco in the position of the garage band who started a trend that the big labels turned into platinum records.

In an era when the commonest reason for a DNF was engine seizure from piston overheating, riders would say, “I stuck it” or, “It tied up.” Therefore I was always amused by the sales slogan of ‘Fullbore’, the oil marketed with Bultacos in the US; “Stick with Fullbore.”

The Metralla 250 road bike passed through Mk I (1962-66) and Mk II versions (thru ’74), well regarded for its good combination of unique style, power and light weight. Boston-area dealer John Jacobson and I ventured forth to lunch one day on one – only to find that its wiring was fed through an unprotected and sharp-edged hole in the frame. Engine stop in IHOP parking lot. Kick-kick-kick – nothing. To get back to the shop, John pulled enough wire through to give the edge fresh insulation to chew on. We made it.

This emphasizes a point; that racers "spoiled" by the generally uniform quality of Yamaha production racers have been surprised by the variability of their European counterparts. One example is the Aprilia 250 twin I examined in the early '90s; its two pistons did not come to TDC together until an offset crank gear key was machined for it.

Some years ago I got a call from a TSS 125 owner, asking whether I could fix the fork dampers on his bike.

“They never had any damping, right from the start. I didn’t do anything about it because I thought maybe that’s how it was supposed to be. But the porpoising really interferes with riding the bike.”

When I disassembled the fork I found all the parts (everything was brass!) necessary to produce rebound damping, correctly assembled. Trouble was, the damper pistons had been made so undersized that leakage swamped out any damping effect. Fortunately it was easy to make new pistons that did fit, with the result that normal damping appeared.

This is not to bad-mouth Bultaco, but rather to reveal an earlier era in which riders expected a new bike to be just a collection of parts. Making it all work was up to the user. Want both transfer ports to open at the same time? Get in there with your right-angle grinder and make it happen. This is hard for a generation of warranty-wavers to grasp, but in those days small factories had limited knowledge even of their own product. As Ginger Molloy told it to me, every TSS engine built went on the dyno. The few that made outstanding power were kept for factory bikes. Average engines went to European privateers (like Britain’s spring migration). Duds were sent to the US, where they were prized by connoisseurs for their “European flair” (to paraphrase the old SoCal hot-rod saying, “If it won’t go, connoiss it”).

Bultaco simplicity meant that a sharp experienced operator could quickly tune for conditions – more compression for short courses, maybe more exhaust timing for longer ones. These bikes were excellent raw material for thinking rider/tuners, accomplishing great things in their hands.

Even experience couldn’t prepare riders for all eventualities. A veteran New England scrambles rider I knew flew off a jump and in the moment of full front wheel rebound, both fork damper rods broke, allowing his front end to drop off.

When Bultaco built a 350 TSS (83.2 x 64-mm) for Ginger Molloy, its compression prevented it’s being push-started by the rider (European GPs were push-start until mid 1984). The fix? A technician kept removing the head, taking it to the lathe, and scooping out more and more material in a series of tries until the compression was low enough that Molloy could start it. This reduced the engine’s power but the result was usefully faster than a 250.

Japan rapidly adopted reed intake for off-road (and Honda in 1982 would show that reeds could work on pavement too) so Bultaco’s 1979 Pursang Mk XII adopted them as well. Japanese two-strokes adopted multiple transfer ports after 1969 but Bultaco was slower to change. The Spanish company’s original combo of very light weight and good power had taken them far, but such a small outfit couldn’t win an R&D race with Japan.

Production was interrupted in 1979, resumed, then ceased in the early ‘80s. In 2014 a new Bultaco was announced – with an electric powertrain.