Bultaco

I recently bought a bultaco alpina 350cc from bord na mona and it turns out the bikes numbers are different the frame is a 187 and the engine is a 138 the guy we bought it off of said it was like that when he got it in 1976 when he bought it off of harry lindsay in dublin so does anyone know how this happened or was it from factory

I guess everyone has their own lockdown projects on the go at the moment. Mine is using up accumulated parts to put a Sherpa together using a late engine in a slimline (91B) frame. I am quite keen to get the bike relatively finished so that I can move onto other things, so far so good except I had some 35mm triple clamps that I thought would be suitable as they had quite a bit of offset but it would seem they have too much. As it stands with the rear shocks measured at 355mm (temporary fitment only to hold the bike together) the wheelbase measures 1335mm (52.5”). Standard is 1315mm (51.7”) on 340mm shocks I believe. Not sure I will be able to get this back by dropping the…

Hi, I'm just wondering if people alter the foot peg position on a bultaco 159, I've read before on other old trials bikes that people alter them so they are lower and further back. What's everyone's thoughts just before I send the frame away to get blasted and painted?

Hi, I'm Scott from the UK, I have just recently signed up on here, I am in the process of restoring a 1976 bultaco 159, I'm wondering if anyone would know the steering bearing number, this is the upgraded taper bearing and race? id like the number to I can source one from my local bearing shop.

Hi Guys, I need to get my Sherpa 199A wheels respoked. Anybody any ideas of a wheel builder near Glasgow or central Scotland?. Thanks

Merry Christmas! Well the Sherpa is finally back together and after a short run up the road in a hailstorm all seems to be working OK. However, my initial difficulty in kickstarting the bike before I stripped her down remains. Surely it can’t be right that the kickstart (which is already high for my short legs) hits the frame (so much for new powder coating!) then the brake pedal and obviously the footpeg is also in the way and catches your heal even if you hitch it up? Is there a solution I.e. an alternative base pivoting or cranked lever that has some additional clearance? I’m used to kickstarting my T140V Bonneville but that doesn’t hit anything on the way do…

Hi, Has anyone have any experience of the Butaco Sherpa Alloy Fuel Tanks currently for sale on Ebay? These are made in India just wondering what the quality is like. The pictures of them show an unfinished tank without a Fuel Cap. Any comments are welcome. Old Geezer

Dear Sirs, Some help identifying these machines would be appreciated. I’ve been trying to get to the bottom of it by the frames. The frame number of the red one points to a standard 60’s 250, but when I look at photographs of the bikes around the same year, the frame looks different. The blue one has no frame number that I can find, but looks to be nickel plated.

Hello, I’m hoping that some of the depth of knowledge on here in the trials world might branch out a wee bit! I am trying to find a clutch basket for a Mk7 Pursang, 360cc, model 121. I can find examples of new and used baskets for other marks but not for the Mk7. I understand that there are subtle differences between the models but I do not have knowledge of what these are. I am hoping that someone might be able to tell me that a basket for a Mk6 might do the job for example? I’m also unaware of whether there are differences between the 250 and 360. the old basket removed from my Mk7 is a 38 tooth duplex with an overall outside diameter of the basket of 118mm an…

Sorry, so many questions... Could anyone from experience please confirm the correct timing for a 198a? The Bultaco UK (InMotion) Workshop Manual in the 'Model Specification Chart' states 3-3.25mm for the T250 - which is the same as the T125. But InMotion have just quoted 2.5-2.77mm - which is the same as quoted in the Workshop Manual for the T350. This would make sense to me as the T250 stroke is the same as the T350 at 60mm; whereas the 125 is shorter at 51.5mm. Looks like it could be a misprint in what is a complicated spec. table that covers something like 20 different models? Thanks yet again!

Can anyone supply original spec figures for wheel rim offset for my 198A - not in the manuals as far as I can see? I loosely built up the rear wheel yesterday and couldn't get near the offset I'd measured before I stripped them down, but if the rest of the bike is anything to go by nothing has been very stock! Wheels are Akront 21" 1.6 - 36T-581 and WM2-1.85" 36-TR-11-78, hubs concentric, new spokes from InMotion and are the same lengths as originals etc. so all stock as far as I can make out. It could be my lacing at this was a first attempt, but I (thought) I'd done it OK!

Hi guys, I Have recently acquired a 199A. The cylinder head has two spark plug tapped and drilled holes, one pointing towards front and one pointing to the rear. The usual central spark plug hole has not been drilled or tapped. This is different to an earlier 199A I owned. The combustion chamber is also a completely different shape to my earlier model. Has anybody any ideas why this is the case? Perhaps the head is off a Pursang for some reason? The barrel is stamped 199A so that seems correct. Thanks.

Ive had my 198b barrel rebored but the guy who did it had an accident with it and had to resleeve it. Im just wondering if anyone could supply the port measurements so i can check that these are correct. Big ask but someone might have a barrel off for restoration

Hi, the rebuild of my Sherpa 198A is progressing 'well' but I have a question on what is the expected / acceptable swing arm free-play and 'stiffness'. I have replaced the nylon/alloy swing arm bearings and spindle with new items, but find that with the newly powder coated frame and new replacement rear engine mount (all from In Motion) its all a very tight fit - requiring the rubber mallet persuader to fit! The result is that although nice and smooth, the swing arm does not freely move under its own weight (a rough measure I've used on road bikes with needle bearings) but requires some force (approximately a 1kg weight placed on swing arm) to move even without the swing …

Hi, the rebuild of my Sherpa 198A is progressing 'well' but I have a question on what is the expected / acceptable swing arm free-play and 'stiffness'. I have replaced the nylon/alloy swing arm bearings and spindle with new items, but find that with the newly powder coated frame and new replacement rear engine mount (all from In Motion) its all a very tight fit - requiring the rubber mallet persuader to fit! The result is that although nice and smooth, the swing arm does not freely move under its own weight (a rough measure I've used on road bikes with needle bearings) but requires some force (approximately a 1kg weight placed on swing arm) to move even without the swing …

Hi all, looking for Ally mudguards for my early M49, obviously I can get them from Inmotion but wondered if there was a ‘more cost effective’ route. Any thoughts appreciated. Also looking for a good used Right hand fork bottom or thoughts on how to salvage a really worn one. thanks , Andy

Advice please, the Sherpa 198A I'm refurbishing currently has 12T front and 40T rear sprockets that are very worn and to be replaced. I didn't get chance to ride the bike before stripping down, so is this a reasonable ratio for a complete novice rider? ⚙️ Cheers!

Continuing the Sherpa 198a strip down last night highlighted a couple more things! Both of the 19mm bolts securing the rear (cast) engine mount bracket were tight (didn't check torque), but there was some play allowing the engine to move slightly i.e. being cast the bracket wasn't a tight fit to the engine mounting lugs. I didn't want to tightened further due to risk of fracturing the bracket. Is this play normal or possible due to wear? Exhaust. Both silences are dirty, rusty and oily but externally fundamentally sound. Theres no indication (ie. welding) that they've ever been opened up and repacked, so can only assume they are as original and so will pr…

Hi, sorry new to Bultacos so I've loads of questions as I strip down my newly acquired Sherpa 198A! My front drum is the 'standard' chrome finish, it is in 'reasonable' condition with a few pits and marks. However, the rear drum appears to have had a steel ring inserted at some point which (possibly due to being unused for years) is dull. Was this a standard modification when chrome wore and/or to improved braking effect? It worked on quick test ride but I've no experience of brakes effectiveness (pedal is on left and rod connected which I understand is more effective than swapping to right with cable). Are ring inserts available for the front drum? And (fo…

hi is it essential to wire clutch nuts and how tight should nuts be handbook says nuts should be fully tightened then backed off 3 full turns my lobito 175 has the smoothest and lightest clutch ive ever come across daft question what sort of wire......some can be brittle it needs ductility??? maybe copper ...too soft??? suggestions please