Parts interchange

[Cribbs74]

So, I have been racking my brain trying to figure out what parts from other models will fit and be correct on my M-151. I am hoping it’s not a one off model and that nothing besides that year will fit. 

I really don’t know how to date the frame either. I assume a part number list might help, but seeing as nobody lists parts for sale under the part number it doesn’t really help me.   

Long story short what year is my M151 and is there somewhere I can go to gather information that will provide me with parts interchangeably.

Frame# JB-1510724

Thanks as always,

Ron

[stevem75]

Bultacos are never referred to by year.  They are referred to by model number.  A M151 is a 326 cc Sherpa T that was produced for a very short period of time (1975).  However it cannot be called a 1975 model year.  If you order parts from any Bultaco parts dealer for a 1975 Sherpa t it means nothing to them.  The only correct reference is the model.  Bultacos were made so that many parts were interchangeable.  This kept production costs down. So for example an engine case cover for a pursang would fit a Sherpa t.   If you have a non matching serial number between frame and engine you’d need to order correct parts for each model number.  Make sense ?   It would be more helpful if you mention what parts you think will need interchanging.   As mentioned most parts will be to an extent.

Steve  

[feetupfun]

Your best bet is to either ask on this forum or phone a Bultaco parts shop. There are thousands of people who know Bultaco Sherpa Ts intimately. Many of them look at this forum.

There is no compiled cross-reference of model parts to refer to.

The parts don't come with the part number marked on them. They did come in packaging that had the part numbers.

Some parts changed during the production of a single model designation.

There were some years when more than one model of 325/350 Sherpa T was released.

Some models were sold for more than a year.

Some parts were unchanged on subsequent models.

You have a common model that will not be hard to sort out.

[Cribbs74]

Thank you,

That does help some, I need nearly everything for the bike, maybe I should start small and work my way up.

The engine matches the frame number so that’s easy. The first thing I want to do is rebuild it. At a glance I am missing the carb, shifter pedal and kicker.

Frame wise I need a fuel tank, air box, rear brake pedal and rear brake hub.

I appreciate your patience while I figure all this out.

Ron

[petert]

In Motion (Bultaco UK) or Hughs Bultaco in the USA

 

[woody]

The parts you mention should be easy to find, carb was 25mm Amal originally but not really worth risking an old used one. Can be replaced with a 26mm Amal/Mikuni/OKO - Mid Atlantic trials have decent deals on OKO carbs. Gear change lever can be had new although used come up on ebay. You need one from a bike with the same side casing as yours which was fitted to all Sherpas from your model onwards, as earlier models have a wider bend for the different shaped clutch casing. Kickstarts again, new or used. Tank/seat unit may prove difficult, not sure if anyone in the States reproduces them, used come up on ebay but may need repair and sealing against ethanol fuel. Airboxes come up fairly often on ebay and the same one was used on the 71 onwards Sherpa to your model, also similar year Alpinas. The outlet to the carb needs to exit from the bottom left of the airbox, so that it clears the sidepanel of the tank/seat unit, not from top right. One from a same year Alpina should also fit. Brake pedal new or used, if used it needs to be from a model from '68 up to your model. Later pedals will fit if you're not bothered about original look. The rear hub was unique to your model and the one before it (124/125) and would be hard to find. A later hub from the next model onwards will fit with no mods other than a different length spacer might be needed  (if you meant a brake plate rather than brake hub, a Pursang brake plate may fit as your model Sherpa hub was based on a Pursang one)

As the previous poster said, Hugh's Bultaco should give you all the info you need.

If you have to split the engine be aware that although gearbox and clutch internals may look the same, there are subtle differences between some models and later parts may not interchange with your crank cases in the case of gearbox, or mainshaft in the case of clutch hub and basket

[section swept]

Here’s a few tips that may help you. Take photos of what you have for reference later or when sourcing parts. Spend some time just looking at and studying pictures/videos of Bultacos and the detail. Get familiar with the model types, you will find that some owners have altered their bikes quite a bit so try to stay with the more authentic builds. Get to notice the frame rail differences as the factory modified and then introduced these changes onto production bikes. Photos of works riders and their bikes can be invaluable when assessing correctness of parts to a model. 

Now put the frame and cycle parts in separate areas or on shelves but keep them apart. For example front wheel and brake in one location, rear wheel etc in another, frame somewhere else and chain and sprockets in a box. I always start with the engine first, break this down into cylinder, head and piston and store away, now you can strip the engine. If you have not taken an engine apart before, get an old moped engine or similar and practice on that first. A manual is invaluable a Clymer is more superior than Haynes but both are useful. The crankcase halves cab be troublesome to spit but everyone has there own ways to do this. I thoroughly recommend that you watch some of the videos on YouTube for Bultaco, the Spanish ones are good some are crap and not all of the methods used are acceptable so be aware. When you split the engine cases some will say you must  use heat on the main bearings, to release them from the cases whereas others including me use other ways....?

The gearbox is quite straight forward, but there are booby traps with the selector forks and a ship that goes on the kickstart shaft. Some of the breather holes made at the factory are in some daft places and when you locate these you may be surprised. You will get no end of help from the members on this site and the parts suppliers in the UK are excellent. A few photos to help??

 

[Cribbs74]

Thanks everyone, I really appreciate the outpouring of help. I was contacted by Tim Weaver so I am now headed in the right direction.

While this is my first Bultaco engine build, I have rebuilt a Triumph T150 engine and a Honda CL77 and CB550 engine. The Bultaco unit appears to be much simpler than those so I should be ok. 

Thanks again for the posts and pictures,they will come in handy.

Ron