How much different are the engine power characteristics between the earlier & slightly smaller capacity later Bultaco 250 models.

In the Bultaco book the earlier 244cc bikes seem to be around 20/21 bhp, the later 238cc engines 14.1 bhp, very odd that they lost 1/3rd their power when reduced by 6cc's.

Edited March 11, 201115 yr by TrialsRfun

The round barrel 250 (M27,M49,M80) motor is quite soft at extreme low RPM but makes reasonable power everywhere above extreme low RPM

The later 250 (square barrel 238cc) makes good power (for a 238) rignt down to extreme low RPM but is not as strong at the upper end as the round barrel.

In trials use the later motor is easier to live with in modern twinshock events, while the round barrel motor is a very nice motor for more open sections and trail riding.

The round barrel 250 (M27,M49,M80) motor is quite soft at extreme low RPM but makes reasonable power everywhere above extreme low RPM

Cheers Feetupfun the above sums up very well the way my Model 124 rides but I have yet to ride a 238 but know of one for sale, must get a ride on it.

Torque is more important that hp. And what the torque curve is.

Smooth power as on my Model 124 is good, it aids turning and makes it easier to find grip than on a bike with sharper power delivery.

The 124 turns better than my Model 199A but that currently has the ignition a little bit too advanced, it kicks when being started and the power pulses are really noticeable. Must retard it a little.

Need to get a ride on a 238, most of the Bults owned by friends are 350 models 325cc.