feetupfun

There are good photos of one of those cantilever OSSAs in a recent VMX magazine. From the photos there you can see one reason why that concept didn't work out that well - there is no space to fit an airbox. I can't help but think that some manufacturers had a bit of a rush of blood to the head at the time when Yamaha started selling their cantilever MX bikes and then the Mick Andrews works bike appeared and seemed to go well. In all likelyhood, the Yamaha cantilever design on Micks works bike did not work as well as the moved-up/laid down twinshock designs later seen on Fantics, SWMs, Majestys and others, due to the higher centre of gravity, greater mass and greater unsprung mass of the cantilever design compared with a good twin shock design.

Yes the wheel hubs are the same on all the twinshock TY175 and TY250 models. However there are some minor differences in the brake actuating arms and brake backing plates of some models - ie some have steel arms while most have aluminium arms and some have inspection holes in the backing plates. The differences do not prevent interchangability.

If it happened suddenly, I would guess that you have a split in the centre section of the exhaust pipe. Have a good look along the welds.

Thanks Tim. That is the most informative story I have ever seen in the mainstream media about motorbike racing. I wonder of there any lessons in that story for us regarding the popularity of Motorcycle Trials? David

Woody who do I contact about buying a replacement ignition to fit a MAR? Thanks David

The 1983 349 is better to ride and harder to get parts for so it depends on how complete and in what condition they are as to which one is better. Why decide anyway? If you like 1980s Montys, just buy both and enjoy comparing them.

I wouldn't single out Majesty parts prices on that. The prices for the Majesty fuel tanks are similar to prices for replica fuel tanks for other bikes of the era.

It's just the brilliant Aussie sunshine ScrumpyJack. This photo shows the colour better

Here is what one of the French aluminium replica tanks looks like on a 250 Godden Majesty

After the discussion on KT250 steering geometry on this string, there has been a bit of experimentation going on over here in OZ. While I was continuing to try multiple different setups with the KT forks, another Aussie just went ahead and tried fitting forks and wheel from a TY250, retaining the KT triple clamps. Soon after I heard how good the steering became, I set my KT up the same and we both think it works very well. KT purists will probably miss enjoying the visual appeal of the polished conical hub and extravagant brake arm setup but once they go for a ride, they may be won over. A word of warning though - the standard TY front guard as seen in my pictures touches the exhaust. It doesn't hit hard enough to affect the steering but does put small scratches in the finish of the guard. I'm working out what alternative guard to use. The KT in the pictures has 340mm shockies and I have also tried 360mm shockies. The bike steers very much like a TY250 now with either length shockies on it. For people with an interest in the change to the dimensions, sorry but I haven't measured anything exactly but by eyeball the front axle is about 25mm rearwards (in-line axle) and the steering head is about 25mm lower (shorter length forks) as a result of the changes. David Lahey

Steve You'll find plenty of things that will interest you in the Honda, Twinshock, Classic and SWM forums. David Lahey

I don't know what sort of terrain you ride enduros in but where I live the landscape is heavily covered with plant life much smaller than trees (regrowth, woody weeds, vines etc) and which typically whack semi-continuously against the barkbusters both sides even when you are riding along in perfect control in the middle of the track. It's not called single track for nothing. When riding in open grazing country or in desert type terrain or on a 4WD track, it is less of an issue. I agree yes if someone is hitting trees there is something wrong with the way they are riding. The person who wrote about using them on a trials bike mentioned catching on vines, not trees - easily done without barkbusters and not a pleasant experience.

Sorry but isn't that a photo of a pre-65 Bultaco Campera? The M10 Sherpa T came out later on and had leading axle forks, a different exhaust, a radial fin head and other differences that are not discernable in that photo.

If you do the rebuilding yourself, you can buy individual parts for Falcons and just replace what you want. That way you don't have to replace the shafts. The parts are not cheap though. I usually only replace the oil seals and the dust seals when I fix seal leaks on Falcons. Not sure of this is the main reason for the variability in seal life on Falcons, but the Falcon seal life can be shortened if you rely on the rubber mountings twisting to provide the movement as they rotate about the mounts. They need to rotate freely on the mounts to minimise side loading of the seal/sliding bearing. I'm happy with Falcons overall (well - happy enough to buy three sets so far) and have done back to back comparisons with the Betors that look just like Falcons and found the Betors have damping that is a bit too heavy for my liking.

I rode with brush guards on my enduro bikes for about 18 years (from when Goddard's Barkbusters were first available) so was keen to use them on trials bikes too when I started using trials bikes for setting out enduro courses in the 1990s. I did try those exact same Acerbis guards on a trials bike (TY250A). For trail riding on a trials bike they are a definite safety and speed benefit by preventing crashes due to things pushing against or catching on the levers while riding along. However for trials work, they made the steering feel too heavy so they came off again.

Here are some facts about what was ridden in our Twinshock Masters event late in 2007. Modern riding rules applied to this trial ie stopping was allowed. Fantic 240 - 1 1970s Spanish - 6 (OSSA MAR, M125, M159, Cota 348, M199, Highboy frame Sherpa T) 1980s Spanish - 3 (Cota 242, M199B, Cota 349) 1970s Jap - 10 (TY175, TY175, TY175, TY175, TY175, TY175, TY175, TL125 special, TY250, RL250) 1980s Jap - 5 (RS200, TLR250, TLR250, TLR200, 250 Majesty) 1970s bikes - 16 1980s bikes - 9 Spanish bikes - 9 Jap bikes - 15 Italian - 1 To me this indiates that at this modern twinshock trial: There was a wide range of bike ages represented. 1970s Jap bikes were twice as popular as 1980s Jap bikes. 1970s Spanish bikes were more popular than 1980s Jap bikes.

I reckon there is nothing wrong with the standard cam or actuating lever on the front of Yamaha twinshocks. I recently did the machining thing on the drum surface and on some new oversize brake linings combined with a new low-friction cable on my Majesty and the front brake is brilliant.

Who gives a fig what their bikes cost to be made rideable? I wanted a 348 for 25 years and finally got one a few years ago but it had nothing to do with wanting to have the most "competitive" twinshock but simply to be able to ride a 348 and to look at it and learn all about it. The way you are telling it, we should all ride the world's "best" twinshock - whatever that is. B*****ks! Everyone has their own idea of what they like and old Spanish trials bikes feature pretty heavily in my favourites list.

Depending on how long your shockies are, you may increase the rate that you wear out the swingarm pivot protector by fitting smaller diameter sprockets. If you have 340mm or longer shockies, you will definitely be compromising the clearance at the swingarm pivot if you use smaller sprockets.

If you replace in-line forks with leading axle forks of the same length and use the same triple clamp offset, the trail is reduced, not increased. There are also many other effects on geometry as described by MichaelMoore at length. The main benefit from changing to Yamaha mono forks on a Majesty is a slight improvement in damping control and spring rate. It is really quite a small improvement. The invisible addition of gold valves (cartridge emulators) in either TY250 twinshock or TY250 mono forks can make a very large improvement to fork damping and is commonplace in Vintage MX and I would assume they are also used in the forks of some pre-65 trials bikes.

The standard chain type for them is 520 and it looks like 520 in the photo. If in doubt, look at a sprocket website like the JT or TALON sprocket websites and you'll soon work it out.

I'm not saying the Aussie rules are the ideal but they do suit the situation here where twinshock competition is quite a low key pastime. I can well imagine that the twinshock competition situation in Spain is far more competitive hence the well defined and well enforced eligibility rules. I would love to have the bike age classes they have in Spain. Not especially to put the bikes on an equal footing, but to encourage riders to ride some of the older bikes that never seem to get ridden here now (our twinshock class covers bikes made from 1965 to 1986). Unfortunately there are too few entries here to allow further splitting up of the twinshock field into bike age sub-groups. One thing that does work well here for machine eligibilty is peer pressure. If a rider does something a bit dodgy regarding eligibility, it usually gets discussed and resolved before the bike gets to scrutineering at a trial. Here is an example: A rider scratch-built a twinshock trials bike in about 1996 which was a visual and dimensional copy of a mid-1990s trials bike but with an air-cooled Yamaha trailbike motor, drum brake wheels and twin shocks. When the bike turned up at a trial, the rider was enlightened about the bike having to be made before 1984 (as was the rule then) and he quickly put the bike back on the ute. As Woody has pointed out, the riders who win twinshock class are usually the best riders and invariably ride well-prepared, standard-looking bikes. There are also quite a few customised but era-sensitive bikes which are usually owned by people for whom the modifications are a big part of the fun of riding old bikes and where they place in an event is of secondary importance. To put things in perspective, the most competitive twinshock bikes (the SWMs and the Fantics) are only rarely seen while bikes regarded as being also-rans in the performance stakes (Yamaha TYs, Honda TLs and TLRs, post-75 Sherpa Ts and Cotas) are the dominant bikes by number.

Woody you said exactly what I was thinking and it reminded me of what happened at the big twinshock trial we hold each November. The older blokes from the era of twinshock bikes, some riding quite lovely and relatively expensive twinshock bikes and some on whatever was available, all had a fantastic time enjoying our bikes and the atmosphere. At the end of the day it was no surprise that we were all beaten by a young bloke riding his Dad's stock standard TY175. Our national rules for twinshock class are: Made before 1986 Air cooled Drum Brakes Twinshock Specific components are not listed in the rules as having to be pre-86 but specials with obviously post-1986 frames and/or motors have been rejected in the past. I haven't seen occasions of later manufacture drum brakes or forks being cause for rejection. Haven't seen any new (replica or improved) frames yet in twinshock here but replica frames or improved frames similar to original would probably be acceptable to use. Modified stock frames are common (steering geometry, footpeg location, shockie mounts)

That's got to be the undercoat surely

Yes it does look quite neat mollygreen. Do you remember which model DT125 the kickstart is from? Thanks David