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About stevem75

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  1. Simple answer. The engine has been swapped out sometime in the past. Simple as that. It didn’t come from Bultaco with a 138 engine. Someone put it in there when the original engine had to be replaced for whatever reason. Bultacos always left the factory with matching engine and frames. Always ! In the uk in the 70’s it was commonplace to swap out engines and frames for tax reasons. But this swap is more likely because the original 187 engine needed repair or replace and it was easy to install another know good motor.
  2. stevem75

    Crank centering

    With the circlip type cases simply heat the case and drop in a cold bearing. Each one will fall into place and rest against the clip. Temporarily install the seal retainer to hold in place. Do the same on the mag side case. Install the seal retainer to help with final bearing placement. Make sure your crankshaft is ice cold. Set it in the freezer for a half hour. Once the cases are ready to go together I use a heat sink that I heat up generously and then let them sit on the bearings and the heat will transfer from the sink into the bearings. This is a nice way to do it instead of direct heat from a blow lamp or the like. Once sufficiently hot take out your ice cold crank and drop into place in the mag side case. Working quickly with the other case drop it onto the crank and the whole assembly if done right will just fall together, torque case nuts to 5ft/lbs and let cool. Once cool eyeball where the crank is sitting. It may be that it’s too far to the left or right. Simply use a dead blow hammer and swat the end of the crank in the direction it needs to go to be centered. I can hear the curses now. “ you should never hammer a crank”. And true you shouldn’t but just a light swat will move it enough to center it and allow it to turn freely. Once done continue with the rest of the assembly
  3. The chrome is the top ring. The iron is the lower or second ring. steve
  4. I’m with woody on this one..... it doesn’t matter if it was for uk export or not. When it arrived in the uk in 74 or whenever it was, it had a one piece tank and seat unit on it. Before the importer shipped the bike to the dealer the original fibreglass tank /seat / side-panel unit was removed from the bike in the crate and the homerlite metal tank unit installed. At some point since then someone put a M199A tank on it. Probably because it was available and fit somewhat well. As to the actual year of manufacture..... that’s not how Bultaco worked . They didn’t make their bikes by year. But rather by model number. But it is fair to say that a model 150 was available in 74-75. And your dmv or whatever licensing agency in the uk needs to give it a year for registration sake. But to call it a 1974 250 Sherpa t isn’t quite accurate. I’d bet the model 124 and 125 Sherpa t were also available new in 74 and it’s a very similar but different bike. Best thing to do is get yourself a parts manual and service manual. These two pieces of literature will help you with everything you need to know about what the bike looked like. What parts were used and how to repair when the time comes good luck steve
  5. That wiring looks correct. Green is grounded through the white wire to the ignition coil bracket. Black comes from the points to the coil. But that kill switch looks suspect. I’d disconnect it and try again. If still no spark then for the heck of it disconnect the white wire from the coil bracket. If still no spark then reconnect the white to the bracket and carefully clean the points under the flywheel. They may just be dirty and slightly corroded. Steve
  6. I also have a 187 and plugs are never an issue. I run the stock femsa points and use a NGK B8ES plug. I do run belray mc1 at 50:1....... maybe a little lean on oil for long wide open throttle but it works just fine. I’d try a little less oil in the fuel mix. Maybe 40:1 and see what happens. Steve
  7. It’s definitely not a bandido engine. It looks like it’s a model 5 kart engine. The D means it’s a 250cc and the 5 at the end indicates 5 speed. They made this engine over a long period of time so that’s why it has the mid 70’s barrel and head. They may have started production of that engine in the mid sixties and continued it sporadically over the years. I’d guess given the higher than 1000 serial number that it’s a later model produced in and around 73-74 steve
  8. The engine looks like a 198. The frame I’m certain is not 198. It looks more like a model 91 frame. The give away is the gusset at the steering stem and the vertical frame tube that extends from in front of the swingarm up to the upper frame tube. So I would say the engine is 1978 and the frame 1972-4 ish. Remember of course bultacos aren’t made by year. But for licensing purposes you need to give it a year. I’m not sure what your jurisdiction requires ... approximate frame year or engine year. Steve
  9. Has your engine recently been apart ? If the new return spring was installed and it’s still not disengaging then there is an issue with the ratchet mechanism in the transmission. This isn’t hard to repair at all once the cases are apart. Usually the problem you are having occurs because the ratchet on the kickshaft isn’t setup with enough spring preload to fully disengage. Barring that there could be other issues with the stopper plate as well. It would be a bit of pain to have to open up the cases but the actual repair would very straight forward and easy steve
  10. Here are a few pics of the 400 prototype engine.
  11. I don’t think the 400 prototype motor was the same as the el mont or the bandito. it was a right side forward kick that directly engaged the crankshaft. It certainly was a gear drive primary though. I do have several close up pictures of the prototype engine. Even the Center cases look different. Having said that some of the peripheral parts were common to other models. Incidentally the 400 prototype engine number is M100. Not to be confused with the 125 pursang that also has this designation. I’m told most prototypes always began with M100 steve
  12. Very nice !! One of only 57 made !!! (Or 58 depending who you talk to) I’ve seen serial #33 and one other one but can’t remember it’s serial. I actually wasn’t aware the M29 had a 5 speed box but it does make sense they would use it. Steve
  13. Yes it is a Montjuïc race bike. The engine is a 4 speed 350cc This engine was used in the bandito and el montadero models. As well the M29 TSS used it. The preproduction Montjuïc road bike that never came to be used this power plant in its early development stage. Note the center port exhaust exclusive to this engine type. I believe the factory called this the “pedrables” engine. Whereas the 5 speed models were called San Antonio. There were only 2-3 of this montjuic built by the factory for 24 hours racing. It was likely loosely built around the 350 TSS but didn’t carry the M29 designation. Highly regarded and exceedingly rare Steve
  14. 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
  15. stevem75

    Bultaco M80

    True prototype bultacos carried the M100000 serial. Before the purists tell me M100 was the 125 pursang please know factory protos always were labelled M1xxxx. They could have been metrallas, pursang or anything bultaco wanted. Most Sherpa T factory rider models were actually numbered model units taken from the assembly line and given to respective riders. Be it M80,92,133,159. Bultaco did whatever they pleased it seems. Vesty has many times corroborated this..... see his Facebook page and pics for evidence of this. True factory Sherpas were carefully blueprinted well set up bikes for lampkin, vesty , soler, bulto etc etc The G on the headstock more than likely was used to identify what the particular tube on the frame was to be used for. Bultaco frames were not assembled and welded at the factory. They were all pre made at another factory away from the assembly line. This assembly plant likely needed identifying marks to know where to place each tube in the jig for welding. Hence the letter stamp. I have a M27 that has the same letter on the headstock. This isn’t coincidence. They probably did hundreds of frames a month if not thousands and each piece would need to be labelled to know it’s fitment. Steve
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