woody

I know the bike you've bought and it is a 1976 model 159 (which would have been available late '75, hence the registration date) This link will show you the 250 version which is similar and will give you an idea of what it should look like. http://www.ataq.qc.ca/galerie/showimg.php?...6_sherpa250.jpg You can buy a book from Bultaco UK giving the history of the Sherpa, also a repro owners manual for your 159.

No, sorry Mick, don't know of any straight swap replacements, never tried the KX pegs. I never used to have any problem with the originals but need lower footrests these days, particularly with modern bars, so whenever I chop off the old mounts I just use modern replacements.

The work required for the extra 20-odd cc really isn't worth it as the gain is barely noticeable. You'd be better off finding another ignition flywheel and skimming some weight off it which will quicken the throttle response (use a spare so that you have the original to go back to if need be)

Unless the Amal is worn out stick with it, they work fine. I had a Cota 350 when they were new and there was nothing wrong with the way it ran with the Amal carb. If the carb is worn you could try a 26mm or 28mm OKO as they work pretty well out of the box with minimal changes on a MH349. Mikunis are a real pain to jet as there are many variants and they use different needle jet/needle combinations and the range of these combinations is huge, there are different slides for the different bodies, so unless you know what you have (if you get a used one) it is difficult to know exactly what to order for parts. As someone else has mentioned there are other issues, different fuel pipe sizes, different inlet spigot sizes on different carbs, adjusting screws on the wrong side etc. If you're Amal is worn out and you are buying a used carb, Dellorto, Mikuni or whatever, it could be in the same state. A new OKO is about

Honda dispensed with 2-strokes of their own accord, initially in motocross, long before the FIM tried to dictate the WTC must be 4-stroke only. All the other manufacurers that had 2-strokes continued to run them alongside 4-strokes. When the FIM said that to compete in WTC you have to do it on a 4-stroke, I suspect that if the other trials manufacturers had told the FIM to stuff their WTC the outcome may have been different. The FIM have no say in what a factory produces and if they realised that the WTC would only consist of 2 Honda Montesa riders they may have capitulated and perhaps the other trials factories wouldn't have bothered manufacturing 4-stroke trials bikes and saved themselves a lot of money - who knows? Certainly not us, only the factory heads. As in enduro, the swing that initially went towards 4-strokes has now swung back to 2-strokes. Today's 2-stroke trials bikes are easier to ride than the Mont/Scorpa/Beta/Sherco watercoolers. They are cheaper to buy, cheaper and easier to maintain and cost much less to rebuild if things go wrong.

The link just goes to the main forum but managed to find a couple of your pictures of the bike you'd posted. I'd heard of the TYZ Scottish but never seen one. I'd no idea they were like that.

Thanks for the explanation - remarkable results from what you've done. Be interesting to see some before and after pictures if you can get them up. The leaving to dry in the sun for two weeks step is going to be difficult in the UK....

A TYZ with autolube, steel fuel tank and steel swingarm ??

Sounds interesting - Can you expand on what you've done exactly

It's a bit hazy in the memroy now but mine had the restrictor in the front pipe removed (essential) but retained the one at the inlet of the rear silencer and the end cap (as per recommendation from Sandifords) I think it is removing the end cap that creates the noise. My mate's had all the restrictors removed. There was no noticeable difference in power between my bike and his, but plenty in noise level... I think the problem with today's 4-strokes is not the fact that they are 4-strokes, more the way they are designed. In certain conditions I could get more grip from my C15 than my 4RT. At one trial i couldn't get the 4RT into one section as it wouldn't find grip so we went back after the trial. My mate and I both tried it and unless we were in 4th gear we still could barely clear the start cards, neither of us could do any better than legging it through. We were doing it in 1st on my mate's 315, clean every time. 4-strokes will grip in mud no problem but the Mont/Beta/Scorpa and Sherco in particular are not easy bikes to ride in mud. The power delivery is too abrupt on all and they spin up at the slightest touch of the throttle in slimy conditions. I've been able to clean a greasy section on my KT250 but couldn't touch it on my mate's Beta 4T, it just span up at the slightest throttle. 4-strokes in our centre (Midland) are definitely thinning out, people have tried them but are slowly but surely going back to 2-strokes. Two reasons most likely, the difficulty of riding them in mud (of which 90% of our events consist of) and possibly the potential cost of an engine rebuild when the time comes (a motocross engine will put a hole in

Yep, I have them in all mine too - The Miller conversion used a thicker bearing but those from Pyramid are the same dimensions as the original as far as I recall.

More likely to be the 4RT as I've found them very good in snow and ice. If I still had my 4RT I don't think I'd bother taking it out in the snow...

As long as it is only WTC they can do what they want

Exactly - started reading the new rule format out of curiosity when I noticed TX1 etc next to the names in the results but lost the will to live before getting to the end. Indoors was a novelty years ago but surely there is only so much interest that can be milked out of watching riders splat and jump up the same obstacles year after year, venue after venue. It appears to have gone stale now. Is this rule format an attempt to regenerate interest or attract new punters. Contrived cobblers springs to mind but I suppose I've never had any real interest in indoors anyway.

Where, as I 've never found them. I also used to have the British World rounds from 1982 and 1983 on video but they disappeared. I can't find these anywhere either on DVD. Duke no longer list them.

There's an update on the Greeves in this week's TMX (who obviously have a scoop over the 'net') An updated version of the bike will be at Telford show. I was unable to post this in the Greeves forum as it said I didn't have permission

The 250 Villiers engine is a very underrated powerplant in my opinion compared to the Spanish equivalents of the time. It has enough power and torque and just needs a reilable ignition. It works fine on the standard points set up but reliability and consistency can be a problem. I'd say the Spanish engines do feel a bit smoother and more refined in power delivery though. I've ridden two bikes with standard Villiers 250 fitted (ie; no Honda, Yamaha or GasGas componenets or reed valve) One I used in the Manx Classic 2 day which had Motoplat ignition and a decent exhaust and it had more than enough power for what is quite a challenging classic trial. The other I have ridden several times both on original points and Electrex electronic ignition. Again, more than enough power and torque for the sections I rode it on. Both bikes had the original bob-weight crank. I think more money than is required can be spent on them to get them running well....

There is a Rickman Montesa Cappra on ebay at the moment. It's not really conclusive evidence one way or the other I guess, but that frame has a manufacturer's plate riveted to the headstock - nothing like the stamp on the Cota.

No real answer to that as it is whatever suits personal preference. In the 70s trials and motocross bars were much higher than today's bars. Although the footrest position was also higher, it wasn't really noticeable due to the tall bars. Today's bikes have lower footrest position, longer front forks, the headstock is higher and the bar rise is lower. Fit a modern pair of 5.5" Renthals on a 70s bike with the original footrest position and, depending on how tall you are, it can feel as though you are bent too far over. On my KT I have lowered the pegs level with bottom frame tubes and fitted 6" bars.

I've just fitted a 26mm OKO Flatslide to my M92. It came with 112 main and 38 pilot. At the moment it has a 100 main jet and a 38 pilot as I was trying it on something else. The needle, needle jet and slide are all as it came with (no numbers on them) I've only just fitted it and it runs pretty well like this but I have only run it around the garden, it hasn't been tried properly yet, but I suspect when I do, it will only require minor tweaking. I have the same type of carb fitted to my 350 Ossa MAR and it is exactly as it came out of the box apart from moving the needle one notch. Bike runs perfectly. To fit on to your M92 you would need an inlet manifold from a later 250 that takes a push on Amal as it is the same size spigot as the OKO or Mikuni - this is what I've done. If you use a push on type from a later 350, they used a Bing and the spigot is bigger so you would need a step down inlet rubber or you would need to machine and fit an oversize sleeve/ring onto the carb inlet spigot to fit the standard 350 rubber. Or you can buy adaptors that bolt onto your existing inlet studs that take a rubber inlet hose for a push on carb. I'm assuming you're in the US so I've no idea what your rules are regarding carbs but OKO is worth considering if allowed (or if your not concerned with rules) As someone else mentioned, Bultaco.com would surely do a Mikuni readily jetted for that bike?

A contradiction surely. Rules are there for a reason, they should be enforced so have to be taken seriously..?? Yes we do it for enjoyment but it is also for the enjoyment of competing and achieving the best result possible - to some people the result means more than the means by which it was achieved and it happens too often - usually by riders capable of winning - eg: badgering observers to alter scores, getting another rider (unknown to the observer that he is a friend) to confirm that you didn't dab on the observer's blind side, or ride outside of a marker, getting a re-run in a section because you were baulked (again, deliberately, by a friend, after marks have been lost in the section) pressuring the observer to give you a re-run after going the wrong way in a section. 'Unknown' riders don't get away with this because the observer isn't bothered about docking an 'unknown' marks as it won't affect the winners result. When one of the 'names' starts badgering, some observers will be concerned that their marks may cost the rider the trial, so gives the benefit of the doubt (even when there is no doubt) All of the above are examples of cheating and if not taken seriously, we just give the cheats free licence to cheat at will

If you have access to an air socket driver and compressor the sudden shock of the air socket applied to the allen bolt is usually enough to crack it free (with the fork compressed as you have already been doing) If you don't, the way I used to do mine was to cut a piece of wooden broom handle to a length where it would just fit into the stanchion (fully extended to about a few millimetres short of the top. Then, fitting and tightening the fork cap would push the broom handle down onto the top of the damper rod and (hopefully) stop it turning. I then used a T-bar allen key and clamped a pair of mole grips to it and then hit the mole grips hard with a mallet to try and shock the bolt free. May sound bizarre but worked for me as I couldn't see any other way of stopping the rod turning (in the absence of whatever the special tool is) On Ossa and Bultaco forks, the damper rod has a slot in the top so you can just put a long handled screwdriver (or similar instrument) down the stanchion and into the slot. The Yam damper rods don't have this so I've no idea what the tool is like that locks it. I've seen other recommendations that suggest screwing a longer bolt into the fork leg drain holes that will screw into and lock the damper rods and prevent them from turning, but I've never been confident that this wouldn't damage the rods or possibly strip the thread in the fork leg.

The Puma bikes do have a slight reduction in head angle, but I have no idea of measurements. However, you can only reduce it a little on the Bultaco as the rear mudguard stay will hit the frame downtube. The Puma bikes have different guard braces so I guess he can get a little extra. The bike with the Beta (or whatever they are) modern forks isn't a Puma. Puma retains the original componenets so they still look like the original. I fitted longer rear shocks on my 340 Sherpa and it steers fine (12mm I think) The sections we ride here aren't the same as the Spanish classic trials sections. Theirs are a bit tighter with less of a run up to obstacles in some intances, given the differing terrain of some of their events, so they have quicker steering, peppier motor set up.

It happens, the middle box on my Sherpa had all the packing blown out or burnt away. I suppose it depends upon the type of oil and petroil mixture used over the years as to the state of what's left. Mine on the Sherpa was very clean inside whereas the silencer on a 247 Cota was heavily gummed up and what little packing left was like molasses. Replacement packing is personal preference I guess, I use Silent Sport wool strands as it is easier to pack in than sheets of fibre matting.