Mototrans 250/4 Grand Prix Motorcycle
Back in 2008 I had the opportunity to photograph a very interesting but little known Grand Prix bike – the Mototrans 250/4. This sole example (plus an extra motor) was built in 1967.
When it does get a mention it is often assumed to be a development of Ducati’s 125/4, however it was not related in any way to Taglioni’s design HERE. Instead it was the work of Aulo Savelli (ex-Benelli) and Renato Armaroli (ex-Benelli and Tecno BMW Formula 2 design and later to work on Ducati’s 4-valve, belt-driven 500GP V-twin).
Their design was quite unusual in being basically two parallel twins joined together. Two 180º crankshafts were were employed as well as twin head castings – each featuring its own cascade of gears driving the camshafts. The heads used two valves per cylinder with an included angle of 63º. Bore/stroke was 44.5x40mm. The gearbox could be fitted with either six or seven ratios. By the time development ceased in 1969 (due to a change in the GP regulations limiting 250cc class bikes to a maximum of two cylinders) problems with the clutch and ignition had been rectified, the later by fitting a belt-driven magneto ignition from an outboard motor, driven from a camshaft.
The claimed weight was 116kg and an output of 50hp at 14,000rpm was also stated. However figures of 130+kg and 42-43hp were more accurate. As a slightly interesting aside, when testing commenced in early 1967, it was likely the first motorcycle to be run at the new Jarama circuit, which was still being constructed at the time.
Its first race appearance was at the Spanish GP at Barcelona in April ’67. In the first practice session rider Bruno Spaggiari (a long time factory Ducati racer who also competed for Mototrans) was 6th fastest, behind such notables as Mike Hailwood and Ralph Bryans on Hondas and Bill Ivy and Phil Read on Yamahas. Final qualifying had him in 14th place but only 3.5 seconds behind pole. However in the race clutch problems saw him retire after only three laps.
The following month saw a 6th place in Madrid then another DNF in September in Guadalajara. Its final race of the year was also in Madrid but the result is unknown. In 1968 Spaggiari once again was entered in the Spanish GP but after practicing on the 250/4 chose to race the new 250 Ducati desmo single, which while being down on power (36hp) compared to the four, only weighed 98kg. The 250/4 was not raced again although development continued. In fact a second, much lighter chassis was planned as well as desmodromic, 4-valve heads for the motor.
The bike, in its final 1969 form, is now owned by a collector in Italy and was successfully ridden at the IOM in 2005 and in Spain the following year.