Following a request from information on TrialsCentral , the thread produced a list of trials models
There are some Bultaco model lists, such as http://cemoto.tripod.com/bultaco.htm , but nothing with specific trials model information. Hopefully this list can provide some more specific information for Bultaco’s trials models.
The Trials Central thread included a post for Woody on the model numbers and some subsequent comments from other posters.
M10 – original 250cc 4 speed radial head 1965/66
M27 – next version 250cc (may have been the first 5 speed, can’t remember) 1967/68
M49 – 5 speed 250cc 1968/70
M80 – Updated M49 250cc with slimline one piece tank seat (available as a kit on the late type 49 before Bultaco standardised it on the 80) 1971/72
M91 – updated M80 250cc with new small front hub, new arched bottom fork yoke iin alloy (previous models steel) 1972/73
M92 – as M91 but first 325cc engine
M124 – updated M91 250cc with different exhaust and rear wheel, new forks no longer tapered fit into top yoke, new shape clutch cover 1974
M125 – as M124 but 325cc
M150 – updated M124 250cc with different exhaust 1974/75
M151 – as per 150 but 325cc
M49 to M151 were essentially a continual design of the same bike. UK models from late 91/92 through to 150/151 were fitted with alloy blue/silver homerlite tanks seat units (homerlite = company that made them in Wolverhampton)
M158/159 (250/325) 1975/76 through M182/183 1976 to the M198/199 1977/78 – New model (the one that Martin Lampkin is usually associated with) with different frame, seperate tank and seat, new exhaust, rear wheel, 250 downsized to 238cc (French tax laws) engine internals and frame changes along the way.
All bikes red with silver frame up to this point (from the factory)
M198a – Now all blue in colour with seperate bashplate, new timing cover with thumb logo, reinforced swingarm with big gussetts up to shock mounts 1978/80
M199a – as 198a but 325cc
Somewhere along the line a 250 model got it’s own frame design but then reverted back to a common frame for both, can’t remember which model this happened on
M198b – Basically a remodelled 198a with new square section swingarm and rear frame loop cut off – white frame/mudguards, blue tank/sidepanels/yokes/forks 1981/83
M199b – as per 198b but engine overbored to 340cc with Pursang piston and fitted with 6 speed gearbox
There were some other comments and I’ll update the file accordingly