Bultaco Alpina design changes

[jimg]

I need to know any (if any) basic design changes of the Bultaco 350 Alpina years 1974 to 1975, 1975 to 1976 and 1976 to 1977.  I do know in 1975, the brake and shifter was moved to the right and left, respectively.  Primarily, I need to know design changes regarding these items: Suspension (travel length) on front and rear, rear suspension mounting points, frame changes (including any engine mounting point changes) and swingarm changes. 

I may need to buy Haynes manuals for each year to get detailed specifics (part numbers), but any help from you will greatly be appreciated.  Thanks. 

  

Edited July 18, 2017 by jimg
Add mfg. and displacement details

[mrb505]

You'd be better off asking about model number differences like m138 years don't really identify Bultacos

ive never seen individual Haynes manuals your probably after Bultaco parts books here's a m212/3 link to one

http://www.custgp.com/a1manual2/Bultaco Alpina.pdf

[jimg]

Good point... So, I'm looking for any design changes for the Alpina as they went through their model number changes (assuming some sort of design changes occurred for each new model number) for the following:

Model 116 to model 138 (~1974)

Model 138 to model 166 (1974 - 1976)

Model 166 to model 188 (1976 - 1977)

As you mentioned, parts book would be better, but even harder to find. 

[trialsrfun]

http://cemoto.tripod.com/bultaco.htm

You need to go through the model list above they are all shown.

[petorius]

I think this is probably you best resource, quite a few subtle differences with frames etc.

https://www.motoguapa.com/BULTACO/ArxiusBultaco1.html

[cleanorbust]

There isn't a Haynes manual, but Clymer did publish one which is still available secondhand on eBay. This is just as detailed as a Haynes manual would be, so possibly worth having if you anticipate a rebuild for example, but covers Bultacos over several years, and is not specific to the Alpina but would include specifications, torque settings etc for it.

[2stroke4stroke]

Actually, there was a Haynes manual for "Bultaco Competition Bikes".  I happen to know where there's one still in the sealed wrapper.  Covers Alpina '72 to '75, though published in '79 so does this imply no Alpinas after '75?

[jimg]

Thanks to all for your reply's.  I've made good progress at finding what I need thanks to your help, except I can't find any specifications (like listed on the motoguapa website) for the Alpina models 165/166.  Again, I'm looking for information regarding any design changes from the previous Alpina model 137/138.  Items like frame and swingarm changes, suspension mounting point changes, engine mounting point changes,  over length, wheelbase length, footpeg height, etc.  Unfortunately, I need to find the "original" specifications on this bike, such as a sales brochure or specification sheet on the bike.  Any copy of such document or source on the internet would greatly be appreciated.    

Edited July 20, 2017 by jimg
spelling correction

[mrb505]

Try to get a copy of this book https://books.google.com.au/books/about/Bultaco_Limited_Edition_Extra_1971_1979.html?id=FZdVAAAACAAJ&redir_esc=y&hl=en

there is a cycle world test of the m187/188 that they claim the only difference to the m165/166 is the paint scheme. Has a good spec list of it.

there is a few other Alpina tests in the book from the day

[sherpa325]

The very first Alpinas were basically a sherpa T with a wide ratio gearbox and a larger tank/seat unit. As they evolved they moved further from the sherpa, however I am pretty sure the frames were still sherpa frames with the addition of a few required brackets/braces. All the ones I have seen for sale on ebay look the same as the same vintage sherpa. Interestingly the M165 has the same bent front downtube that was only used on the 1975-1977 250 sherpas [m158, mm182, m190] which would confirm that it is a sherpa frame. The 250 and 325 sherpa's had different frames for those three years. I would assume most measurements would be the same as the sherpa t of that period.

Cheers Greg

[twinnshock]

I have a model 166 and can confirm that the frame is basicly the same as the same year Sherpa but has differences to lugs for the different airbox and also the brake light switch. However other than that that bike is quite different. It has some components from the Frontera/Pursang ie fork yokes (tripple tree if reading this other side of pond) that change the fork trail so it has a different wheel base.

The engine looks the same but internally is also quite different to the same year Sherpa having different bore and stroke, (bigger capacity) compression ratio, porting and gear ratio's and I think crankshaft balance weight but not sure on the last one.

My bike is an early example M166  and it still has in perfect condition the original stainless steel front and rear mudguards. I think these were only fitted to a limited number of bikes as they were quite expensive to produce. Most had the Sherpa aluminium guards fitted.

The problem with trying to answer the original posters question is that spec could change mid production depending on what parts were in stock and at this distance of time impossible to answer many of the small insignificant changes that took place. Sales brochures can be misleading as oftain published quite some time before a model was actually produced.

Stuart

 

[shakennstirred]

Yep the same with a lot of these smaller manufactures .

Changing things mid year and with whatever parts are available.

Beamish were the same, can make getting the right parts a right pain .

Edited July 21, 2017 by shakennstirred

[sherpa325]

I agree, the sales brochures could be inaccurate and couldn't be relied upon 100%. The problem trying to work out the Alpina model changes is that most of the bultaco nuts that I know only have one Alpina that  they have picked up during their travels and I don't know of anyone who specifically collects Alpinas as opposed to Pursangs and Sherpas. Getting back to the Alpinas though, they definitely ended up with different hubs and forks to the Sherpa and the 350 used a 64mm stroke engine. A rider in our club fitted a set of Alpina forks in his Sherpa T and they work without hitting the frame downtube on full compression, which can happen with the standard ones, so I would assume they are not too far away from the standard sherpa fork. It would be interesting to know what difference there is in the forks and how much they alter the wheelbase and steering geometry, I did ride the bike for a short period and it did steer quite differently to my standard setup but it did have fatbars fitted with bar raisers and the bars were a lot further forward with the new triple clamp.

[jimg]

Thanks again for all the bits of information.  Seems that I'd need to line the different models up next to each other to determine frame differences, shock mount position, fork yokes, etc.  But, I'm leading to a conclusion that from a model 137/138 to the 212/213 models, there was little structural/geometry design change.  Perhaps, I should chase down frame changes that the Sherpa went through during this period would provide better results. 

[sherpa325]

The Sherpa geometry was pretty much finalised in 1975 with the M159 [325]. A longer swinging arm [15mm-guess] was fitted to the 183 and subsequent models. Its easy to pick these swinging arms as they have a rectangular bottom shock mount, with additional holes for pillion pegs, the earlier version had a triangular bottom mount. It is interesting to note that the sales brochures did not add the extra length to the wheelbase? To the best of my knowledge models 159,183,191,199 would have had the same dimensions, shock mounts, engine etc, with the exception of the wheelbase change. In 1979 M199A had the engine raised and the bottom frame tubes removed but this wouldn't apply to the Alpinas. The 250's had there own frame from 158,182,190 - they also had the longer singing arm from 182 onwards. Their frame is shorter and has more ground clearance, different forks and triple clamps.It is easy to pick up as it has a slight inward curve in the front downtube. In 1978 the 250 M198 went back to the same frame as the 325.

Hope this helps, Cheers Greg