woody

It's a Yamaha frame, not a Godden, so not a frame kit, non-matching numbers could simply be due to an engine swap at some point. As a Majesty conversion it could have been a 175 or 200, or it could be as above, the original engine was swapped at some point. Not unusual on a near 40 year old trials bike. I don't know enough about the 175 Majesty conversions to say whether that is a proper Majesty conversion or not.

The original yellow was a pretty insipid pale puke yellow. I used 1021 when I did mine, much nicer, but it is too deep if you want original. Signal yellow is too 'yellow' as well. I think 1016 is closer to original. There have been other mentions on the forum of it being British Leyland yellow

Lovely One of my favourite bikes and very under rated. Had the Cota 350 model back in the day but all the sections were hopping sections then, needing plenty of clutch and brake for tight turns and the clutch was it's biggest problem. Not on a par with the other later twinshocks for trick riding. But for today's classic events, where very little clutching is needed, fantastic bike

The original bolt is just a normal bolt but with a very thin head to clear the return spring, and a shank that is just long enough for the stand to pivot on. Probably no longer available. I just us a normal bolt and machine the head down in the lathe, or use a button head allen bolt. Doesn't really matter if it has no shank and is threaded all the way. Can't remember though if it is 10 or 12mm, but all you have to do is measure what diameter and length you need.

Only the later seal carriers had O rings, no gaskets, and they were machined to take them. Earlier models used gaskets only. Only the clutch side has an O ring on the crankshaft. If the plug was the correct colour and dry it's unlikely it was burning gearbox or clutch oil. My Ossa has been burning gearbox oil and the piston crown, head and crank are coated in a thin grey sludge. Not sure what you mean by 'wants to rev'. Normally a weak mixture caused by sucking air will cause the engine to run on when the throttle is closed. An engine burning gear oil won't do this, it will just run roughly. Are you sure the carb isn't worn, have you swapped it with the carb from the other bike to eliminate a possible cause, if that one runs correctly.

I understand now, I thought from your original post that it was just that one hole that was not positioned correctly, so yes I'd have done what you've done as you're not altering the unit in any way. I thought you were going to have to elongate the hole in the back plate

The problem I'd have with modifying it to fit is that if it didn't run properly when fitted, for whatever reason, they could refuse to accept a return as it has been altered / modified

In the ideal world, I agree with you However, this is Electrex world...

No, no lights, indicators or reflectors of any kind needed However, your tester may not realise or understand this

They've actually withdrawn their technical help phone number from the website, they only have a sales number now You have to email them for technical help and wait for a reply.

*************** website shop probably which is where my mate got his from http://www.todotrial.com/es/tienda-tt/piezas-aluminio-trial/results,1-1600.html?language=es-ES Don't know why the website name has been blocked, that wasn't me.

I'd suggest you're going to have to be very forceful with them as a mate of mine has an issue with his Montesa ignition which has been going on for 3 to 4 years now, their support service has been abysmal. It was returned to them again about 3 weeks ago for probably the third or fourth time and they still haven't got in touch with him

Just happens I have these which I took for someone else a while ago. No idea if they are better or not. You also need to make the T shaped bracket that fits between the two rear head studs as the bottom head steady mount bots to this

There are generally two clutch / crank flywheels on the Sherpa engines, a big thick single weight on the 250 and a bigger double weight on the 325/340. The smaller and thinner single weight fitted to the 198b may be offset on the ignition side by using the heavier ignition flywheel usually found on the 325/340. When they built the 198b they were probably scraping the bottom of the parts bins and using whatever was left. I also have a '76 325 motor which has a small weight like the 198b but it uses a double row primary chain and clutch basket. I think the thin single weight originates from the Pursang.

From what I've seen of them and from what is fitted to my own, that seems to be the usual size flywheel that was fitted to the 198b As for what it does to the engine, I haven't finished rebuilding mine yet so never ridden it, but you need to ride it for yourself as everyone's perception of good/bad is different. Easy enough to fit the bigger weight normally fitted to the 250 if you don't like it though.

The person at the VMCC who did most of the dating work isn't there anymore, so it may take a bit longer to get things processed with them

You're much better off phoning them you know, the web site just shows that they sell pistons. If they haven't an 83.25 in stock they can get them

They've been modified by smoothing them out, helps them rev a bit more I think. In smoothing them out like that it also means a little metal is lost from the edges so they end up a little oversize. Normally the cylinder would be matched to them. My modified 199b is similar as is a mate's 199a that he recently stripped for a rebuild. Standard Ossa MAR ducts are like that

From your picture, the spring tensioning nuts are wound pretty far in and so is the pushrod adjuster. It could be the clutch needs re-setting as it could have too much tension on the springs to release properly. If you search the Bultaco forum for clutch adjustment or setting up clutch etc. there have been previous topics with good info on how to do it correctly. It's possible to get a Sherpa clutch to work with quite a light one/two finger pull on the lever.

Try John Collins at Port Talbot, JC Motorcycles. Used to be a Bultaco dealer, knows a lot about them and has a stash of used parts. May have some suitable forks. It sounds as though someone has probably damaged a fork in the past and replaced it without realising there are differences. One of the the problems of 40 year old dirt bikes.... You never know what they've been through.

Ossa MAR fork tubes come in two different lengths and the longer ones, from '76 on are too long for a Bultaco. The earlier MAR forks are shorter and may be too short for a Bultaco so make sure you get them to measure them exactly before you buy them

I can't imagine they cast different legs so I'd assume it is the tubes that are a different length. As pointed out in the above post your frame looks correct for a 190 as does the bottom clamp. What I can't figure out is the 190 tubes shown in PSchrauber's picture as they don't look like they are from a 190... The knurled part looks as though it would sit below the bottom clamp but maybe it's just an illusion. The tube in the bottom picture looks more like a 190 Overall fork length can be shortened by fitting a longer alloy spacer on the damper rod which prevents the fork legs extending to their normal length so you could consider doing this if you found a pair of longer 350 forks. With your current forks though, if one is longer than the other, the longest can only extend to the overall length of the shortest so you would still have the correct overall length, so maybe there isn't an actual problem - unless I'm overlooking something. Or, to maintain the correct head angle with 350 forks, you could machine out the shoulder in the top yoke which prevents the forks being pushed through, then just push them through to match the correct 250 length.

Not sure how well 250 length forks would work on a 350, they were shorter because the 250 frame from '76 - '78 (up to the model 190) was different from the 350, particularly the headstock position. The bottom yoke was different as well. From the M198, they went back to using the same frame as the 350.

The forks fitted to the 250 models from '76 - '78 were shorter than those fitted to the 350 models so maybe someone has fitted a 250 stanchion at some point? I've no idea exactly how much shorter they actually are.

Just love the selector drum