woody

I think he was yes, and as far as I know the sale records only show the name of the rider for supported riders. Otherwise they just show the dealer that Commerfords sold the bike to, so maybe ties up with him being one of their supported riders.

Try TY Offroad,Colin is quite knowledgeable with Honda parts http://tyoffroad.weebly.com/

Useful to know, thanks for that. Website is here http://www.novaracing.co.uk/

Have you tried Bultaco UK yet? You never know what is still available in Spain and they have the contacts. They were able to get me a new final drive sleeve gear for my 340 and gearbox parts for those are as rare as hen's teeth. Spokes - it's 50 years old, so are the spokes, and as you've damage to some spokes which could have been caused by a hard impact, I'd be reluctant to trust those that are left not to break as well if you have another. If it was mine I get the wheels rebuilt. Original spokes aren't available, neither are the nipples, you'll have to use new, choice of finish (galvanised, stainless, butted or not butted etc) is personal preference

221 is a 175cc, not 125cc, and is essentially a sleeved down model 190 250cc Not a great bike with 175cc, but much better than the 125cc which was as much use as a chocolate teapot. The 175cc bike can at least be converted back to 250, making it a decent bike again

They appear original Bultaco stamps to me. If you look at mine, the 1 is bigger than the other numbers, as with yours, as is the J bigger than the M, and if you look at the M on the 198B engine, the M is at an angle like yours. It seems they were always neater with the frame number than engine number. I think to re-stamp the engine number, with the amount of metal that would have to be removed to completely erase the original number, it would appear obvious. If it is a replacement 6 speed engine that someone has fitted and re-stamped to match the frame, they would only have to redo the last four numbers, not the whole number. If you're thinking it is a 5 speed crankcase converted to 6, proper engineering work is required to do that and you have to ask why would someone do it in the first place, as they'd have to have the six speed parts to begin with. Assuming someone would do it if the original 6 speed cases were badly damaged, I'd have a guess that if they had the facilities to convert a 5 speed crankcase to 6, they would have the means to repair the original cases instead.

This is the 199B, didn't think I had a photo but I have

This is mine from the 198B which is worse than my 199B

Wouldn't worry about the engine numbers being in a straight line, mine aren't either and the number on the 198B is even worse.

John, MK2 needle is different from the MK1 needle

At least with the Amal there is infomation available for the original jetting / settings, so you have a starting point. From memory I think pilot is #20, needle jet #106, main #160 and slide #3.0. There is only one needle for the 2-stroke concentric and it should be centre groove. I've never had to raise an Amal needle, they've always run fine with the clip on the middle groove. What's confusing is when you raised the needle which richens the mixture, it weakened the pilot as you had to turn the air screw in which richens it more... That isn't right as raising the needle will richen the mixture at the bottom of the rev range, so you'd expect to have to wind the airscrew out a little if the increased richness caused it to run lumpy at idle or coming off idle. As for individual jets and the part of the rev range they are supposed to affect, I've found to the contrary of general thinking. A weak main jet can make a bike pink at very low throttle opening when the engine is warm as I've just had this very problem with my Ossa. I had a 130 main fitted (Mikuni) instead of a 160 and the bike nearly blew itself apart on the road, even with the choke on, and this was at around 25mph in top on a bike that will touch 70mph, so that gives you an idea of how little the throttle was open - and the main jet is only supposed to affect 3/4 and above throttle opening. It's possible you have a partial blockage in the pilot system, so it would be worth soaking it in carb cleaner and blowing the pilot circuit through with an airline, or if you can, get it sonic cleaned. Also, what spark plug does it have. Too soft and it will pink when warm. Generally, an NGK BP6ES or 5ES works fine. Avoid race plugs as they are no use in a trials bike, they're designed to run constant high revs, they can easily foul up in trials engines. Check the jetting against spec first, also make sure you haven't got a 4-stroke needle which is weaker than the 2-stroke, is longer and has much less of a taper. I'm not sure if it woould even run with the 4-stroke needle but worth a check I guess. I forget what the 2-stroke needle is stamped. but it has a U in it I think. You didn't say whether the bike has always done this or whether it only began after you tweaked it at that last trial.

With Barnett plates, I've found that you can only use 4, as mentioned previously, but to keep the correct thickness of the pack I use one steel plate on the outside, so 4 Barnett and 1 steel friction plates and 5 drive plates. As also mentioned previously, drive plate goes into the basket first. I run all six springs on my Sherpas but with the nuts backed off to get a light pull on the lever. You can't back the nuts off very much as they will foul the inside of the case, so I machine the nuts to half of their thickness. This means they can no longer be lock wired, unless you drill new holes, but I've never had any come undone. I screw then in until the thread of the studs is just showing and then start fine tuning from there. First thing to do is disconnect the cable and back off the centre adjustment screw in the basket. There should now be a lot of free play on the clutch arm. Rotate the clutch arm as far as it will go clockwise and then screw in the adjuster screw until you see the arm move. Back of the adjuster until you have a little free play in the clutch arm. Now position the clutch arm on the spline so that it is roughly 90 degrees to the cable run, so that the cable is pulling the arm straight towards it rather than having to rotate it around the spline which will increase its resistance. If the arm is as straight as you can get it, it will offer the least resistance when the cable pulls it. Reconnect the cable, adjust up slack, and you should now be able to pull the lever and operate the clutch. If you can't you will have to repeat the above until you can - if the clutch arm or splined shaft is not positioned correctly you can end up with the 'cam' of the operating arm fully rotated against the pushrod before you even pull the lever, so it can't move any further and will feel solid. So if all has gone to plan you should by this stage have a little play in the clutch arm to pushrod and a little play in the cable on the clutch lever. Once you have the clutch plates moving you need to ensure that the pressure plate is lifting evenly by adjusting tension of individual springs. I've found that on all clutches there can be as much of a difference of one or even one and a half turns in (or out depending on how you're measuring) between springs to achieve this, they're never all at the same tension. Also ensure that the faces of the slots in the basket in which the friction plate tabs run are perfectly smooth and free of ridges. Once you have the pressure plate lifting evenly, check the pull on the lever, you should be able to operate it with just one finger. If it feels heavy, back off each spring half a turn and experiment like this until you get the pull you want. With the greater friction of the Barnett plates it seems less tension can be used on the springs which helps. Now put the bike on a stand, stand on it and kick start it. If the kickstart is slipping, put a quarter of a turn on each spring and try again until it starts. A bit of slippage on the kickstart isn't unusual but obviously you don't want too much, and bear in mind it may increase when the oil gets warm under normal use. Best way to start the Bulto is clutch in, rotate the kickstart to about 3 o'clock, let out clutch, let kickstart up slightly and feel for TDC by pushing gently. When there, lift kickstart on ratchet until it's in a comfortable position for you and push hard, rather than kicking or thrashing at it. It's less likely to slip that way. If you kick and thrash at it, they can slip on the clutch. Now ride it to see how it feels and adjust accordingly. Only when that is all finished, put the case back on and fill with oil. Also, it's worth checking the alignment of the pins that hold the springs and buckets as they are quite weak and can be moved off centre in relation to the holes in the pressure plate. Before fitting the springs and buckets I check their alignment and centre them - easily done by just bending them with a screwdriver through the pressure plate hole. I figure it's best to have them centralised so that there is no binding on the springs / buckets. It's a bit fiddly but this is how I set up the clutches on my Sherpas and I can operate them with one finger. It's just takes a while to get the right leverage with no or just acceptable slip on the kickstart. Edit: - Forgot to mention that for a clutch arm, I use the Sherpa front brake arm as it is longer so requires less leverage, as the standard clutch arm is quite short. If you're using the standard clutch arm, you probably won't get as light a pull on the lever.

Found it, on a Swiss twinshock website. Some more pictures for info http://www.twnclub.ch/classic_trial_files/Italjet/italjet.htm

I can't get the history page to load from that site but I think the second version of the 250 had a black engine. It was only one model and they went back to green like the 350 after that (until the white tank model I mean) I'm sure I've seen a brochure picture showing a 250 black engine

Hi Lorenzo, thanks for the reply Funnily enough I was talking about this after yesterday's trial and my mate who is an engineer said the same thing. When I said that the thread gauge that fitted had 1/4 20 stamped on it and it was in the whitworth selection, he just laughed and said it doesn't mean it's a whitworth. He also said it was most likely the 3/8. I didn't understand what the figures meant as I could see the diameter was much bigger than 1/4, so had no idea what 1/4 related to. All I know is I spent a while looking through 100 odd whitworth taps for one with 1/4 20 scribed on it. If I found one I was just going to check the thread in the same thread gauge to make sure it matched. Needless to say I didn't find one with 1/4 but I found plenty of 3/8 but obviously had no idea they were probably the correct size...

To be honest, I haven't a clue on engineering matters when it comes to thread sizes etc. I can do drilling and tapping though which gets me out of most fixes.... I measured across the threads on the shank and when I measured it again this morning using the other bolt on which the threads are less damaged, it measured 9.5mm, so based on what's been said above I thought maybe it isn't metric... I was just assuming it was with the 9mm measurement. Luckliy my grandfather was a top rate mechanical and electrical engineer with the old GEC and we inherited his tool set. Sadly I didn't inherit his skills.... so 99% of it I haven't a clue what to do with. There are thread gauges though which I found and it turns out that that the bolts are 1/4 whitworth.... But I've no idea what the threads inside the yoke are as the bolts won't freely screw back in. They were hard to remove I remember, but put that down to them being corroded in after 40 odd years. But trying to get them back in I could see that the tip of each thread was being flattened so I guess that when fitted they were persuaded into a thread they don't fit properly with a bit of additional elbow power. Friggin' butcher. So back to what I can do, drilling and tapping. Problem solved by drilling out and tapping to 10mm ( not without snapping two drills... grandad would be proud...) Thanks to all for the suggestions above

From what I can see of the airbox, the filter from the last model Sherpa looks as though it could fit as the filter and hose are a complete assembly, see link http://www.inmotiontrials.com/product/bultaco-sherpa-199b-air-filter-on-hose/ The inlet hose rubber should be a standard part which are easily available. They come in different diameters depending on bike / carb combination, I'd imagine yours needs the hose that is 35mm ID both ends http://www.inmotiontrials.com/product-category/carburettor-bultaco/.

Hi John, it's the same both sides I've now found what appear to be the bolts, which are allen bolts. I'm pretty sure that they were usually hexagonal, they are looking at pictures from other M49 and M80 I've owned. Putting the vernier across them, it reads 9mm. They screw in but they are tight as the yoke was powder coated and the threads have muck and dirt in them, as well as maybe some powder coat. They need cleaning out with a tap. At least if these are the bolts I can establish the correct thread now and get a tap. If they have been stripped in the past and re-tapped, the mind boggles as to how you strip the thread of a fork pinch bolt - both sides...... and on a steel yoke too, not even alloy More investigation tomorrow, I'm off out for a beer after a day of various Bultaco traumas.

There are two effects of lightening the flywheel, one is that the motor will pick up quicker due to less mass, the second is that it will stall easier at very low revs if it is too light. The former is good if you ride sections that need immediate response to sharp throttle openings. The latter means that you will have to ride the bike constantly on the clutch at low revs to overcome the possibility it will stall. With the standard flywheel the SWM will drop to a virtual standstill without using the clutch, plonk very smoothly at this speed and will pick up smoothly with no snatch. With a flywheel that it too light the bike will not run as slowly without the clutch and will jerk and snatch, meaning you have to slip the clutch to overcome the snatch and stop it from stalling. If you're used to modern bikes and don't mind clutching everywhere then it's probably not going to be an issue. In the end, it's all subjective and personal preference First thing you have to ask is do you really need to do it as if you're not riding sections that need the engine to pick up revs very quickly there is no point. An SWM should pick up revs quick enough to cope with any classic trial and probably any easy route in a modern club trial. Get a spare flywheel and take half a pound off it and try it. If you want more take another quarter off it until you get something you're happy with. First thing I'd do is ride it as it is, as you might find it's fine... As regards the lighter flywheel making it grip less in slippery conditions, it won't affect the bikes ability to grip, what it will do is make the bike spin up and break grip easier but it will still grip, just requires more input from the rider.

Does anyone know the thread size of the bottom yoke pinch bolt on the earlier Sherpas please. Looks as though they are 9mm but I've no idea what the pitch would be. 8mm is too small and 10mm too big. This is for the steel yoke with the single pinch bolt used up to the model 80. I have to get some new bolts and also a tap to clean out the threads. I seem to have misplaced the original bolts... And I thought it was only Ossa and Montesa that used stupid odd number sizes for their threads... First time I've come across anything other than even number sizes on a Bultaco

They all had green frames so yours could have been stripped and repainted / powder coated. Unlikely a small firm like Italjet would change colours for different countries. Yours looks to be the green coloured 250 but with a white tank, due to the black engine and hubs, but after 30 years you never know what's been changed. As the exhaust is already off, just lift the head and measure the bore. Around 70mm and it's a 250, 80mm and its a 325.

I wouldn't even know where to start looking for those. The pistons / bush have a fibre sealing ring around them and after 30 - 40 years they can be worn out so they don't seal as effectively any more. Early 70s Betors don't even have the fibre ring, just a plain piston / bush. You can make new ones from PTFE card which is on ebay. Use the old fibre ring as a pattern and to get the thickness of card required, then cut new strips with a blade. I'm no engineer but I've done it ok, just a bit fiddly

Back in the 70s, which was the most prolonged run of twinshocks the bikes had the footrests set high to keep them clear of snagging obstacles etc as the bikes didn't have a huge amount of ground clearance. The bikes were also ridden differently with virtually no use of the clutch, the bike was kept moving and the positioning of the footrests enabled the rider to move around a lot on the bike to weight it in turns, keep balance over obstacles etc But the biggest difference was the bars which were a much higher rise than today's bars. Therefore although the footrests were higher set, with the higher bars the riding position wasn't uncomfortable. I'm 6' 3" and never had any issues riding the bikes then. Later twinshocks and aircooled monos carried on with the higher footrest position as ground clearance increased but the bars got lower meaning you were pitched over the front more. No idea if this was by design or they just never thought about it but the style of riding these bikes differed from the 70s era with more emphasis on stopping and balancing and hopping the bike around. It took up to the mid to late 90s before the footrests got lower as with the riding style still evolving into what it is today, the need for the rider to be more upright, rather than hunched over grew. There was also no longer the need for the bikes to have 13 - 14" of ground clearance as modern riders began to ride more on the back wheel, keeping the front light or in the air, so grounding the bikes wasn't so much of a problem, plus being a lot lighter than older bikes they slide over stuff easier. So the modern stance is to stand in the bike as they are designed to be ridden in straight lines now (my opinion) with riders hopping them around turns (better riders that is...) rather than the old fashioned way of steering them with both wheels on the ground. Standing upright on the modern bikes is the best position for using the suspension to move the front and rear of the bike around. The old style was to move around a lot on the bike to lean the bike where necessary when riding a section and the higher rests and riding position made this easier. It's actually quite hard to ride a modern bike in that old style - for me anyway... The problem with the earlier bikes now, if you are tall, is that with the high rests and low bars, they can be pretty uncomfortable to ride, depending on your height. 40 years on, I can't bend as well as I did at 15... so on all my bikes I've lowered the rests and fit the highest bars I can get which is only 6", compared to 8 or 9" from years ago. I think just lowering the rests is the best compromise but some people set them further back too. Depends on the bike and how far but if they are too far back it can put more weight on the front as the rider is again pitched forward to reach the bars and this can negate the reason for moving them back in the first place, which is to get more weight on the rear for grip... Steepening the head angle is another of those subjective matters. It is better in terms of stopping the front pushing in turns in theory because there should be more weight on the front. A GasGas is much more planted on a full lock tight turn on a slippery surface than my Bultaco for instance. But I've ridden a few twinshocks with altered steering and the results have been mixed. Some felt ok, some were ruined as the front pushed everywhere when on lock. It doesn't always improve the bike Besides, today's classic trials are nowhere near as hard as a centre trial or national from the late 70s early 80s, so there isn't really any need

BellaVista in Spain may have them. I needed a final drive sleeve gear for my 340 Sherpa which is different from the 5 speed sleeve gear, and was able to get one from them, through In Motion Bultaco UK We sent the old one to them so that they could match it up as there is no parts diagram or part numbers for the 340. Worth keeping in mind if you can't find part numbers. I think to make a 5 speed box fit the B cases, the layshaft bearing housings may need boring out to take the different bearings as the 6 speed uses small diameter needle rollers. You might also need to use the 5 speed selector pawl mechanism as I tried a 5 speed one in my 6 speed and it doesn't work due to it being machined differently on the inside where it engages with the drum Probably easier to just use 5 speed cases

I wouldn't say a 'pup' either as you don't know it's history, who built it or whether it's been changed around in later years. It's not hard fact obviously, just an opinion, but based upon what little I know, I don't think it is a bike built for Ossa UK for one of their riders. With regard to being a MAR frame, I can't see it, as based upon the number of changes that have been made to make it very different from a MAR, some of which would have been unecessary, why would they have? The Ossa UK bikes that were converted MARs were unaltered at the front half as there was no need to