woody

If you want the previous threads on this topic just search the Yamaha forum for the word broom and it will return 4 topics with the info your after. Best investment you can make is with Machine Mart for their electric cordless impact driver for about

I don't have pictures but the Jumbo doesn't have a rear engine mount on the frame, it uses the swingarm spindle if it's any help.

If it is 1972 it is a MK1 MAR and as far as I know they didn't have the frame number stamped onto the headstock of the MK1 like later bikes (1974 onwards approx) I think if anything, the MK1 had a dealer's sticker on the headstock which carried the frame number.

They are most likely too short, you need to establish the correct length of your Fantic shocks which will be probably be around 13.5"/340mm. The bush size for the Fantic is probably 8mm, it doesn't say what these are so the bushes may need changing in order to get them on the Fantic. As to whether they are suitable for use on a Fantic depends on how seriously you use the bike. For trials use they are going to be too hard in both damping and spring rate. As they are probably about 1" too short this will lower the back of the bike and make the steering rake longer which will effectively destroy the trials geometry and handling. If you are just using it as a field bike where handling doesn't matter you could probably use them.

Assuming all carbs are new and functioning as they should:- The bike will run fine on the MK1 Amal 26mm (or 27mm if still available) the MK2 Amal isn't worth the extra expense, an OKO 26mm will work virtually straight out of the box with minimal changes (it did on my M92 and 199b) a 26mm Mikuni will be a sea of misery to jet unless someone can give you the spec. A new MK1 Amal is the original fitment so will bolt straight on. The MK2 Amal, OKO and Mikuni will need an adaptor or manifold change as they are all push-on fitment not bolt on. It's a personal opinion but I doubt that if you were blindfolded and tried the bike with each of those carbs correctly set up, you would be able to tell any significant difference between them. The OKO and Mikuni probably run a little smoother off the pilot but it's subjective to be honest. For what it's worth, my old M92 325 which my mate now has runs very well with a 26mm MK1 Amal, silky smooth off the bottom and revs to the moon. I've tried a 28mm Mikuni and now have a 28mm OKO on my 340 and can't tell any difference.

Hi Giles - I think you both use the same colour. In fairness (as I didn't mean it in a critical way) the green you use seems to be the same as the decals that were available many years ago when the bikes were current and for a few years afterwards until supplies dried up as I remember buying them myself from local dealers or Millers. The bikes were originaly fitted with fibreglass tanks and these were removed when they came to the UK and the alloy tank fitted. The original factory decals wouldn't fit as the tanks were different shapes so new decals must have been made in the UK for the UK shape tank. Somewhere along the line the colour changed to a darker green from the original factory colour (I still have an old 1970s set which are waterslide, which I used as a pattern to have some new decals made for myself around 1990 when none were available, albeit in a lighter green) As an idea of the shade of green they used at the factory, have a look here at this catalogue picture which shows the lighter green of the original colour scheme http://www.ataq.qc.ca/galerie/showimg.php?file=/Mus%E9e/Ossa/ossa1974_250MAR.jpg

Assuming it is the same as other Montesa clutches, the whole basket comes off with the plates as one assembly together, so you only have to undo the nut and remove the basket. You only need to compress the clutch if you want to remove the plates from the basket, which is done after the basket is removed.

Hi Hamish - arrived home at about 3pm Monday. Took your route via Ripoll and Berga and up to Toulouse through the tunnel. Had a bit of fun with customs coming back into Dover who decided to give my van a check over, including luggage out and sniffer dogs. Really enjoyed the trial, some fantastic sections, some quite difficult but nothing silly. The standard of preparation of the bikes out there was again very impressive and the difference in performance between one of their modified bikes compared to standard is quite significant. If it is possible for me to ride there again next year I will definitiely do so. Long way to go but worth the trip.

You can buy an aftermarket original style steel silencer from Bultaco UK, or an alloy WES silencer from Bultaco UK or Sammy Miller. I fitted a WES to a 1974 247 and it was quiet, although I'd also cut open, cleaned out and repacked the centre box too.

Thanks, useful info to know. I've just been dismantling my 350 engine today but got stuck with the cush drive sleeve. It won't budge on this one and I've bent two 3-legged pullers already. Retired after conceding round 1, I'll have to fight it again another day. Fed up of it for now...

It's the thin end of a wedge yes, but if you know what to do and have the facilities, a 240/300 can be ported and fitted with a reed to make it perform like a later engine anyway and there is nothing wrong in doing that. It's just totally unecessary as more power doesn't have any real benefit in either the Miller or Normandale rounds. One or two riders regularly put TY175 and Whitehawk/Majesty 200 at the sharp end of the results. More power has no bearing on success in the sections in these trials. There is nothing, even in the hardest round (Colchester when it's wet) that a standard 200 Fantic can't do. Of more concern would be bikes appearing with hydraulic clutches and discs as they do offer a significant advantage regarding machine control and placement of the bike in sections.

Thanks for the info, fingers crossed I don't run into any problems

Mine was like that in the Jumbo when I got it. When I found it I thought great, that's why the clutch action is poor (well, crap more accurately) I got another from Martin Matthews and when fitted tried the bike again. Total disappointment, the clutch action was still the same... Not sure I'd go with 3 springs due to the uneven pattern but I used 4 in the Jumbo without it slipping when trying to get a lighter clutch pull, so you could try that. There are 4 grades of clutch springs for the Rotax which are in stock at Rotax UK if ever you want to try different springs. I'm still trying to cure the graunching, grating, juddering when feeding in the clutch in 3rd or above. It wasn't caused by the broken lug, it's normal. For a replacement clutch centre, try Martin, or try Malcolm Herbert as he also has a stock of used Rotax/SWM parts for sale (on here as Malcra) or this is a link to his blog http://www.twinshock.org.uk/

It's from a Spanish (I think) designer and it is his take on what the Sherpa would have evolved into had Bultaco not folded. He's done the same with a Gripper. There is a Sherpa 340 (here in the UK) that has been modified along those lines, frame tube and top shock mount, but many years ago, not recently.

You can't have rules like that. As an example, when I had a 1977 325 Bultaco (in 1979 as it was a couple of years old when I bought it) I found the forks much poorer than the Ossa I'd had before. If I could have afforded it I would have fitted some Marzocchis. There was no rule against this. Similarly, other people were fitting Yam or Suzuki wheels to Spanish bikes for the better brakes. Even Bultaco riders were fitting airboxes from earlier models to the later 199 model as it was considered better. People also altered the frame for head angle, suspension mounts to suit their own requirements. All perfectly acceptable I've been riding my 340 Sherpa regularly for the last 4 years or so in modern as well as classic events (far more modern than classic in fact) The forks are just as bad as they were when I had my old '77 model. So when I get the chance I am going to fit a Marzocchi fork and yoke set from an Armstrong or Fantic. I already have a Fantic front wheel in it as the chrome liner on the original is scrap. Your proposal would prevent me from doing this, or from making any of the mods mentioned in the previous paragraph, yet they are all period parts. Similarly, anyone with a Commerfords 340 couldn't ride it as the frame is not standard. I don't pretend to know what the answer is to try and stop twinshock development, if that is what will actually happen. I do know however, from experience in riding in many events, that whatever rules are in place, that there is a question of who is going to do the scrutineering, who knows the intricacies of each model, what part belongs on what bike? I've also seen zero scrutineering at many big events, regardless of what the regs say, so still bikes compete with inelgible parts, whether it is Pre65 or a mono converted to twinshock (very rare ocurrence) So far, twinshock mods in most events have been sensible, very few have gone 'over the line' and most riders seem to accept what is correct and what is not. Sure there are a few out there who will push it, but the current rules for the national championships state that the bike must have been twinshock at original manufacture and have drum brakes fitted. That alone should be enough to keep it in check. A lot has been said of fitting later Fantic engines with reed valves to 300 and 240 models, but Yams had reeds in 1974 and Ossa UK fitted reeds to their bikes in 1975 so if someone fits a 305 reed engine into their 240 instead of having their 240 cylinder converted (perfectly acceptable is it not as it is use of old technology), is there really any difference? Not that a 240 needs it, but that's a different matter.

Metisse - How big a problem is this fuel thing? I'm riding Santigosa as well and driving from Calais at midnight Thursday. I caught a bit of it on the BBC news tonight. Is it accross the whole country? There is no way my van will make Spain on one tank so I'm going to take a jerry can full as well just in case, but I didn't realise that there may be blockages at peages. Is that a reality? May have to look at other routes if it is - a van with UK plates won't have much success getting through any blockages I suspect.... OTF - I honestly wouldn't think of modified Spanish twinshocks as cheat bikes. They are a different concept altogether from the Pre65 scene here. I've ridden some Puma 340 Sherpas and a Vasquez 340 Sherpa. They are still Bultacos. Ported engines, reworked exhaust internals, modified fork internals, altered steering angles - yes, they have all these things but they are nothing that couldn't be done when the bikes were new (and probably were on some factory bikes) and nothing that individual owners who have the skills haven't done over the years. I can't comment on the mono to twinshock Aprilia TX300 as I haven't seen it but I'm surprised that it has been done as when I was in Robregordo last year it was a pleasant surprise to see how the modified bikes still look basically the same as the standard model (apart from the anodised parts and extra polishing and chroming) They are just 'tuned up'. They are just able to get optimum performance from original components with some clever mods and the bikes perform very impressively. Interestingly, there was one Bultaco that had a 38mm Paioli front end in it (drum brake, not disc) and no-one I spoke to approved of it, it was considered a step too far.

The MH349 tank is the plastic one, not fibreglass

Not a Majesty, engine hasn't been lifted. Shock mounts are in a different position from Majesty. Seller may genuinely believe it's a Majesty, I'm not suggesting someone is knowingly trying to pass off a copy as a proper one as I have no idea

Thank you

I have a set of forks from a 303 Fantic that aren't working very well and need setting up. I know that on later forks such as Fantic 305 or JCM Europa, the compression damping was controlled on one leg and the rebound on the other. I've no experience with 303 forks so don't know if they work in this way or have conventional damping with compression/rebound controlled on both legs like older forks. Any help appreciated.

Clutch cases are always available on ebay, the one on the 340 is no different from other models, any Sherpa since 1975 has that clutch case as well as Alpina and Pursang. The ignition cover would be harder to find. However, any competent welder can easily repair them with a TIG welder.

If they're talking about trials bikes it's rubbish. They're referring to tuned up motocross bikes I would guess as there are a couple of blokes in the US who can really tune them and make already fast bikes absolute flyers. Standard fitment to both trials and motocross was the same rod and it's accepted that it wasn't up to the job for really serious motocross use. The standard rod is fine for trials

I'm becoming a fan of Homebase 3 in 1 silicon/mastik sealant. No rim tape. They are an utter pain in the a*** to fit - just too wide to sit properley in the well, won't lie flat all the way around the rim and rarely seal

Clutch arm - it's in seriously small print in the title This is from memory but I think the arm should just pull out after it has been lifted as far as it will go, then turned as far as it will go then lifted again. Can't remember which way it turns. I think this is how it comes out, same as on a YZ engine (I think again) Memory is not so good but give that a try.