1974 Bultaco Model 92/125/133?

[m lawson]

I have a 1974 Bultaco Model 125. But I see that they made three models during that year, the 92, 125 and 133. I can't see any glaring difference, does anyone know what the differences were?

[bultaco49]

Hi

The series 'a' model 91 (250) and the 92 (350) had the older type of frame with the single post and swept round sub frame under the seat as model 80. The series 'b' had the chrome moly frame, at this time still with a post under the seat but with side rails from under the tank to the lower rear frame. Model 124/125 had the same frame but the exhaust was changed frome chrome to matt black and the clubfoot spark arrestor replaced the triangular box. Side stand was also moved from frame to swing arm. Rear hub was also changed.

I've never seen a model 133 Sherpa which I think was a cancelled model and the 134 was a prototype 350.

UK models of this era were distinctive by the blue/silver Homerlite tank/seat unit. (UK law changed and fiberglass tanks for use on the road were banned). There is a picture of this sort of tank on the front of the Haynes manual.

The post under the seat remained until the model 158/159

Historia de la Sherpa T will have all of the detailed changes, or, of course, Don Morley's Spanish Tials Bikes if you can find one under

[big john]

I have a model 124 (250) 1974 with the seat post, but the triangular aux silencer had gone by then, they only used that until late 1973. The 1974 bikes ahd the 'banana' rear silencer, the forerunner to the clubfoot.

Sidestand is fitted on the swinging arm on 1974 on models.

Big John

edited for accuracy!

Edited December 18, 2008 by Big John

[woody]

I have a 1974 Bultaco Model 125. But I see that they made three models during that year, the 92, 125 and 133. I can't see any glaring difference, does anyone know what the differences were?

They only made two models in 1974, the 124/125 and 150/151

The 91/92 were 1972/73

The 133 was a 350 prototype and only a few were made - probably what Malcolm Rathmell won the '74 European championship on. That bike was at Malvern 2 or 3 years ago and had a few subtle differences from the production bike, the tank/seat unit for one.

There aren't many differences between the 72 - 74 models, known as the Slimline range because of the sleek tank/seat unit (although a lot of UK bikes had the Homerlite alloy tank/seat unit in blue/silver fitted) As mentioned above, the early 91/92 bikes had a different frame, later 91/92 models, 124/125 and 150/151 shared (effectively) the same frame. 124/125 and 150/151 had a nice Pursang style rear hub which was two halves bolted together. 91/92 had forks which were a tapered fit into the top yolk which had no pinch bolts, the later bikes had normal forks. Exhaust has already been mentioned but 91/92 had chrome front pipe, triangular spark arrestor, 124/125 had black front pipe and the boomerang silencer (the clubfoot without the club) and the 150/151 had the clubfoot. The 150/151 had the new style clutch case that lasted throughout the remaining models. Sidestand was relocated as mentioned above.

In 1975, the model 158/159 came out which was a complete overhaul and marked the end of the slimline range (159 was the model known as the Soler)

PS - '74 model 125 is a nice bike, either as a slimline or homerlite version.

[swooshdave]

As mentioned above, the early 91/92 bikes had a different frame, later 91/92 models, 124/125 and 150/151 shared (effectively) the same frame.

Any idea the serial number for the frame change?

[woody]

As it happens.....

Still have a note of them from when I was checking my own. Series 2 frame on 91/92 models was introduced from:

9100727

9202387

124/125 and 150/151 frames may have had their own minor (as in unoticeable) changes but I wouldn't know. They look the same.

The serial numbers are from Bultaco's own figures so they should be right. However, they only list the model 49 as having one frame change during its production run but there were two. Series 1 with single tube under engine, upright shocks. Series 2, single frame tube under engine, angled shocks with seat unit altered to accomodate relocated top shock mounts. Series 3, twin frame tubes under the engine, like the M80 and which was the basis for the Kit Campeon.

[swooshdave]

As it happens.....

Still have a note of them from when I was checking my own. Series 2 frame on 91/92 models was introduced from:

9100727

9202387

124/125 and 150/151 frames may have had their own minor (as in unoticeable) changes but I wouldn't know. They look the same.

The serial numbers are from Bultaco's own figures so they should be right. However, they only list the model 49 as having one frame change during its production run but there were two. Series 1 with single tube under engine, upright shocks. Series 2, single frame tube under engine, angled shocks with seat unit altered to accomodate relocated top shock mounts. Series 3, twin frame tubes under the engine, like the M80 and which was the basis for the Kit Campeon.

Too bad someone can't extract all the information from your brain and put it into a database...

[feetupfun]

Dave I will be getting the numbers from two more M49s just after Christmas at a rellies place which may help with when the changes were made for that model. I think one is a series 3 and the other series 2.

David M49-00100

[m lawson]

Thanks guys for the wealth of information, that is just what I was looking for.

So far the project has been fun although the engine was a bit more challenging than I thought it would be. It was froze solid, and after trying every trick in the book I ended up having to cut the connecting rod in half! But it's starting to come together. A perfect way to while away the winter nights.