sherpa325

They didn't even make 300 gassers when the alleged incident occurred Brian Robin Trump 650

A prime example of fake news!

I had a couple of the larger bikes in the 90's and they both suffered from the same problem as you describe. I ended up putting smaller main jets in to get them to rev freely, and if I remember correctly they were a lot smaller than the standard ones that they came with, sorry I cant remember what the exact sizes were though. Also mine were new out of the box and had this issue, I had in the back of my mind maybe it was to stop over revving the bike during the break in period!

My first bike was a second hand series 1 M49 which I thought was fantastic, but things changed pretty quickly back then and the series 2 M49 was a big improvement so I bought a used one of them, no sooner had I bought it and the slimline M80 came out. I didn't buy an M80 but did purchase a new M92 series 1 325 when they came out, what an improvement. Lots of riders used to retro fit the new parts when they became available rather than buy a new bike. It was common to fit the folding footpegs, new handlebars without the welded on levers, a couple of mates even fitted the square cases to the earlier models. Both of my 49's had the ubolt clamps which were a pain in the rear end and I wouldn't be surprised if riders fitted the later triple clamp when they became available. It was a bit of a statement if you had Renthal bars, a set of Dunolp 2 ply tyres and any Sammy Miller parts on your bike. Interestingly the book Historia de la Sherpa T shows the M80 with the ubolt clamps so I would guess mrb505 is spot on. Anyway I wouldn't think it would be too hard to find an original triple clamp. Cheers Greg

I am pretty sure the ubolt type was used up until the M91/M92 series 1972

428 is 1/2 inch and was last on M92 from memory and is noticeably smaller than the 520 which is 5/8 inch

I have never had any dramas with the original ball bearing style and unfortunately the same can't be said for the tapered type in most gasgas bikes I've had in the last few years which seem to require more maintenance than the ball bearing style. I also recall reading somewhere that the Moto GP bikes all use the ball bearing style because they give better feeling. Cheers Greg

From memory I used a piece of aluminium flat bar which was bolted to the old coil mount, the bar extends forward towards the headstock, the new coil was then mounted off that.

I am not a Matador expert either, but I am pretty sure the thicker poly type round tank stickers came out on around 1974 or thereabouts, prior to that all the Bulllys I remember seeing had the flat standard sticker type.

When the bikes were originally on the market in the early eighties you could buy a complete kit [from the manufacturer] to convert them over.From memory it included a gear shaft that went all the way through the engine and came out though the primary cover, there was a bung in the cover that was tapped out revealing the pre drilled hole. The kit included a brake pedal and all the necessary parts. I don't remember putting a seal in the primary cover but it is a long time ago.If you have some engineering skills it wouldn't be that difficult to make the shaft, the shifter spline would be the biggest hurdle. Cheers Greg

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

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.

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

I think the 280 conversions use a gasgas piston. Most people I know are using electronic ignitions,newer carburetors [Keihin, OKO, Dellorto, Mikuni] and some are reducing flywheel weights, which can be done by using a 250 magneto on the 325's and likewise smaller flywheels on the primary side. The problem with the lighter flywheels is that obviously the motor revs better, but it puts extra pressure on the already average brakes as you lose engine braking. Would love to see some photos of the 370 as I would assume it would be a copy of Martin Lampkins bike if not one of his. I think the factory riders tried a 348 long stroke engine[64mm] in 1976 or 1977, not sure of exact year, but they all went back to the 325 except Martin Lampkin who apparently ended up with the larger bore and larger stroke 370. I am not 100% sure on the factory riders engine sizes so if anyone can add more that would be great. Cheers Greg

From memory they used to rub on the top of the swinging arm and also on the top of the bottom frame rail that the bashplate is welded to. From the 199a on a rubber protector was fitted top and bottom to stop the problem. Inmotion sells these, but they will not bolt directly on your model without a bracket being made for the top run, whilst the bottom one bolts directly onto the alloy bashplate which was standard on that model but not on the 159. So yes they can be fitted but it will require some welding and fabrication on your part. Cheers Greg

All the current new bikes use 28 keihins which is what is on my 199A and it works fine. They are a very clean crisp running carb that works well even if the jetting is slightly off. The 199A came with a 28 Bing so I would stick with 28

The OKO is a copy of a Keihin, I bought a cheap OKO off ebay and it was rubbish. Apparently the genuine OKO is good , so I assume you should buy one off a dealer rather than ebay. Keihins are 28mm and you can buy OKOs that are 30mm but they are bored oval to obtain the larger size, the width is 28 but the height is increased to 30mm

Good to hear, I prefer the keihin though over the mikuni however

They are great to deal with, even living here in Australia. Parts generally arrive in about a week which I reckon is pretty reasonable considering the distance. There prices, knowledge and service are fantastic.

I was just wondering, did you put a centre case gasket in before you tightened the cases up? I remember when I put my 199B back together, with the motor on the bench I was not convinced I had all the gears, but once it was installed in the bike with all the accessories, clutch, chain & sprocket etc was I able to find all the gears easily and it shifts perfectly, but as I said on the bench it didn't feel as positive as the 5 speeds. Cheers Greg

I would be interested to know how many turns your air screw is out, every time I hear your bike it sounds like it needs to be wound in 1/2 to 3/4 of a turn

Borrow your Dad's glasses

Netleys bike sounds like it needs a larger pilot to me,however its very difficult to sort out just watching a video

I see you have bought an OKO/keihin for your Montesa, I would stick that on the Bully and see if you have the same symptoms

It does take a lot of time and patience to get them running crisp, this video is maybe three years old and I think it would have had a Keihin on it. I have run with a dellorto but I would have to say the keihin/oko is the easiest to get running crisply.