woody

Bad picture but my money's on a silver engined Beamish

I'm no technicaL expert but ask yourself this before removing metal from anything - did every TY250 mono sold back in the 80s and 90s detonate? I can't remember it ever being an issue. None of mine did, none of my mate's bikes did, none of our club/centre rider's bikes did. It just didn't happen. If they did and a design fault with the squish band was the cause, every biike would have had to have been modified in the way described to cure it. Recalls to dealers/importers etc. None of this ever happened. And would Yamaha have let a problem like that continue for the 10 year production run of the bike? If everything is set correctly on your engine, timing/carb etc. and there are no air leaks etc. a probable cause is a choked exhaust - you don't say what condition the exhaust/silencer is in - I'd start there if it was me and I'd definitely ask Nigel Birkett about the squish band issue before having anything modified. He has just rebuilt an engine for a mate of mine, 270cc and ported - no modifications to squish band on that motor and there is no detonation - there wasn't before either. I'm perfectly happy to be proved wrong, just can't see it myself, if it was designed wrong they'd all detonate and they don't.

Don't know whether Mick sells them himself over here, but as they are advertised on Todotrial website, you may be able to buy them through Todotrial. If you e-mail them and ask, Horatio speaks good English so he will be ale to answer your question. The only problem is that buying direct from the Spanish suppliers means you have to pay by bank transfer usually, they don't do credit/debit cards payments or paypal.

Just realised my mistake, I didn't look at the picture properly - because the post initially mentioned Jon Draper on a Bantam I just assumed the bike was a Bantam without actually looking at it and couldn't understand why that bike changed anything..... Now I've looked at the picture properly I can see it is a Bultaco

I know the older ones were rebuildable as the pair that I bought from Sammy Miller about 7 or 8 years ago were. They were advertised as rebuildable also back then if I remember correctly. I haven't seen the current Betors but was told they are no longer rebuildable, they aren't advertised as rebuildable but that means nothing... is this incorrect then, is it the current Betors you're saying can be rebuilt? If so getting seals and O rings from local stockists shouldn't be a problem and it means the damping can be altered to suit personal preference if necessary whilst they're apart.

ANY air cooled machine..?? - I think you'd be pushing your luck using 80:1 on a Villiers/Ossa/Bultaco etc. and isn't the sort of advice to give to someone who may do it and suffer a seized engine. Castrol TTS at 50:1 works fine in the following bikes - Yam TYZ, KTM 300EXC, Ossa, Bultaco and has never gummed up rings or silencer or anything else. The TYZ could easily run on 80:1 but I prefer 50:1 - it doesn't smoke, runs perfectly clean, pick-up is clean as a whistle and it doesn't have a coked up exhaust. I have no technical knowledge of oils to back this up, just the experience of what I have used with no problem. There is no way I would ever run an Ossa or Bultaco (air cooled machines...) on 80:1

Instead of guessing and/or relying on information from people who may or may not be qualified to give a definitive answer on forums, why don't you phone Nigel Birkett and ask his opinion on why the bike may be detonating. There is nothing he doesn't know about Yams. I know nothing about squish bands but find it hard to believe Yamaha produced a bike for nearly 10 years with a wrong squish band. I owned 3 monos, an '86 'S' I bought new, and '87 'R' and and '88 'R' both bought used from a local rider so the history was known. NONE of these bikes detonated at all, not even once. In fact, the S model was quite firey and I had at least 2 head gaskets fitted to soften it off, maybe 3, can't remember now. That presumably increases the squish but there was no detonation. I ran them on 50:1 as I do everything else with no problems. We have a rider in our club who owns a mono Yam and it is the foulest sounding and smelling bike I have ever heard. It is loud, smokes and pinks like crazy. The reason it does this is because the exhaust system is choked. The rear silencer needs repacking and the middle box may be coked or have broken baffles. With those fixed it would be a different bike. Check the condition of your exhaust so that when Birks asks you the question, you at least know the answer to give him. It's a common cause of poor running and detonation.

It doesn't matter which brand you go for it is pot luck whether they work how you want them to work when you get them and also whether they last for any length of time before blowing a seal. I have a pair of Betors on my 1968 Bulto and they work pretty damn good, my mate has a pair on his '73 325 and they feel dead by comparison. I have a pair of Falcons on my Majesty and they are probably the best twinshock shocks I've ever had, the back of the bike works brilliantly. However, they've lost their oil after 2 years and the bike isn't used every weekend. Somehow they still work well... I've 2 pairs of Falcons for my Ossa. One pair work well and have lasted about 6 years before blowing the seals. The other pair which are supposed to be an identical set-up are nowhere near as good and give poor performance...!!?? I've Falcons on my C15, work well but have blown the seals after 2 years, bike not used every weekend. Yes the Falcons are rebuildable and on a DIY basis if you can refill them with nitrogen (air is probably just as good but you need a correct valve attachment otherwise you won't get the air to stay in when you remove the pump as you need 90psi) If you send them back to Falcon for rebuild it will be new seals and rods, not just seals and it isn't cheap. There is also the matter of turnaround time which may or may not be quick. Rockshocks can work well but you may need to try different valving and springs from the standard set-up if you are say 14 stones or over as standard set-up has softish damping and spring rate. They are rebuildable and are easy to work on. However, they are the most expensive (discounting Falcon alloy shocks which are head-spinningly expensive) NJB come in 3 specs, standard, expert and trickshocks, standard being the cheapest at

Are you sure the stator is off a Montesa? The green Ossas, TR77 and TR Verde did have Motoplat points fitted as standard instead of electronic ignition, then they went back to electronic on the Grippers. Have you replaced condensor also? Bing carbs work well but are very finicky with the float level, are you sure it isn't flooding which is why it's cutting out. I may have the carb specs for the Ossa's Bing, I'll check tomorrow

You will struggle for 'off the shelf' parts for Montesas but with a bit of hunting around you should turn up the parts you need. There isn't a one-off specialist for old Montesas but Bultaco UK's offshoot, In-Motion, are starting to stock and accumulate parts for other brands so they are worth a try for used parts. Sandifords I think, have sold all or most of their old stock of parts to a guy in America so doubtful they will have anything now but you may as well try them if you haven't already. Jeff Bungay at Mainly Spanish is no longer trading I believe due to ill-health and his stock has been sold on to someone who specialises in Ossas - Marlimar - but I think In-motion will probably end up with the non Ossa stuff. You could try Gordon Farley as they were Montesa dealers years ago, Steve Goode may also have some stuff. Wakefield offroad also break bikes and have used parts. As regards the actual parts; Fuel filler cap may well be common to other models so try some of the breakers as well - Ellastone Offroad in Rochester 01889 590186, A&B Autos in Cheadle. Keep an eye on ebay as Mont stuff is regularly auctioned. Clutch and gearbox filler caps as above. I'm not overly familiar with Montesas but if there are two filler caps then yes, clutch filler will be on outer clutch case, gearbox in the centre crankcases. Forks - use about 180cc per leg of 10 weight as a starting point. Not sure of the quantity for clutch and gearbox but a Bultaco is 300cc of ATF in clutch and 600cc of light gear iol in gearbox - the Mont shouldn't be too far off these. Hve a look on Todotrial Classic website Todtrial classic as they have parts lists and spec sheets available for some bikes. It's option 10 on the left of the page when you get onto the site. The Montesa 349/4 has the same engine as yours and it may give quantities in the manual. Chain guide/protector - as far as I know there aren't aftermarket parts but again, they may be common to the other models that had these fitted so again it is a case of trying the names mentioned above. For a spacer you will probably have to get one made - unless a piece cut off some old Renthal bars will work. Finally, if you look through some of the parts on ebay at the moment, either Ossa or Montesa and look for a seller called trickytrials, he has used parts for Montesas so it may be worth contacting him and asking wether he has the stuff you need. For the telephone numbers of the dealers/breakers mentioned above, just google for them or use Yell.com as I don't have them to hand apart from Ellastone which I have imprinted on my mind... Hope this is of help to you and good luck. Another old Mont saved from the scrap heap is worth the effort.

On the 6 speed Frontera the ratios are higher - 1st gear on the Frontera is midway between 2nd and 3rd on the 199b

Yes, it's an alloy tank off an earlier model. Bike looks nicely finished though

Well, it seems to me that the only person getting worked up is you as you choose to come on this forum and denounce bikes you admit you have no interest in and a traditional series you have no interest in riding in.... sure is a funny old world

How many have I won..?? irrelevant. I wouldn't win overall if I was riding Bou's 4RT because there are better riders in the series than me, but since you ask, I have placed 1st in class B (2nd overall) in one event and had other 2nd and 3rd places on an Ossa MAR now and again without any trick riding obviously. However, if you were at any of these events you would have seen Nick Shield win some outright - yes, beating the modern bikes too, on a 340 Bultaco or a Majesty and he does NOT trick ride. Your ramblings, yet again, are not based on any fact whatsoever.

FFS man, where do you get this tripe from. That is complete and utter B*****ks and you'd know it if you'd ever ridden one of the events. Give it a rest with these bull**** posts - your credibility is long gone

More crap - you really haven't a clue why people ride the bikes they choose to, have you

Try Honda, you may get a bit warmer.

Ellastone Offroad have a Beta TR34 Stripey that they have broken for parts, may have the same coil as 87 model? 01889 590186

Well, given my luck and track record with punctures, that's probably just how it will be....

If you're ok with standard footrest position I'd leave them but if you're not move them. Forget originality, that's fine for a museum piece but if your using it you have to be comfortable. If that means moving them so be it. I was ok with the footrest position on these bikes back in their day but 30 years on a knackered back, neck and wrists means I can't ride them like that any more. They get moved.

Too many Majesties around - no early Cotas being ridden at all - do the Cota, be nice to see some Monts out there, I've a MK4b that I must get done sometime for the Miller series. Who cares what it's worth. Enjoying them is what counts.

If you go onto Todotrial Classic website you can download a parts list/manual for a 348. Use the link below which takes you onto Todotrial Classic, then select option 10 from the index on the left of the page for the manuals. They are mainly exploded parts diagrams I think, rather than an instruction manual on how to strip and rebuild the bike, but may be useful to you. Todotrial Classic

It always amuses me when someone posts something like this which is of no assistance to anyone - why not just say what the simple modification is as that would be far more helpful. How can they machine shoes to the exact diameter of the hub without the hub?

It all depends on whether the spoke holes in the Yam rim are at the correct angle for the conical hub, you may be lucky and they are, but I guess only the wheel builder can tell you that. Are you going for the conical hub for appearance or for a better brake. If the former I'm assuming you already have the hub. If it's for a better brake, see if you can find a complete Grimeca front wheel assembly as fitted to Fantic/Beta/Garelli/Armstrong twinshocks as generally they are a pretty good brake and they're conical. My Majesty front brake is tragic. You'll just need to have a fiddle with the spindle fitting as it is a larger diameter than the Yam one.