heavydabber

I had a new Rev3 after Shercos/Gassers and to be honest, I didn't think that on uphill stuff in particular, the back wheel followed the ground as well as on a linkage bike, it was like the shock just didn't react as fast no matter what I set the spring or adjustment at. The fact that Beta went back to a linkage on the Evo speaks volumes in my opinion, even after 8 years of development the Rev3 couldn't match a linkage set-up

Definitely not in the Twinshock spirit.........

Even if in the name of weight saving it is unreliable or inherently weakly constructed? There's a significant difference between progress and a blind alley. Look at road-racing two strokes from a few years ago. Tuned to the point of unreliability and eye-watering maintenance costs, new pistons at 500 miles, cranks at 1000 miles for instance. It wasn't sustainable, let alone affordable or environmental. We can make bikes as light as you want with the technology that's available nowadays. The only limit is how many people can afford it. And most trials chaps don't have pockets all that deep....?

Some early Shercos had the impeller shaft machined from too soft a material and the seal wore grooves, causing leakage as lineaway says. A new, harder shaft was supplied under some warranty applications (I know, I had one, but it was a long time ago, 2001/2 model, I think). The kit was new seals, bearings and a shaft and it was priced at @ £25, I think, would depend on the age of your bike

That's a spot on analysis D of 2, especially with regard to the way trials bikes have developed. Have they/the sport just become too specialised? Are the bikes now just too expensive for something that only comes out of the shed once a week or fortnight and can't realistically be used for anything else? If 100 people learn to ride a motorbike, either round a field or with an instructor, how many of them will actually take up trials? 10? 5? Less? Has the sport become so specialised and expensive in terms of skill and machinery that it's no longer attractive to the mainstream to participate? We're talking £5k-£6k for a new bike and £300+ for a good set of riding gear. And that £5k-£6k bike is essentially manufactured as a disposable item to be changed every year for the newest model, the manufacturers would have us believe (with the depreciation hit). That is not a small amount of money for a couple of hours a week entertainment/competition, plus membership and entry fees, insurance, road tax etc etc. Certainly not in the current economy.

I wonder if the FIM's increase in the minimum weight limit for WTC bikes wasn't intended to pass down into making production bikes a bit more robust? When it gets to the stage that Joe Punter's £6k bike is so light that it's snapping in two, that's not doing anything for either the manufacturers or the sport in general. A year or so ago there was an interview with Scorpa boss Marc Tessier where he predicted the coming downfall of a couple of un-named manufacturers. Enduro etc bikes were subsidising loss making trials bikes, which were sold too cheap and in insufficient numbers (and I don't know how you square that circle). He might well have been right though.

Yup, I'd go with this, the stresses are directed straight up the main frame side-member which is obviously already there, so why not use it for a shock mount?. From an engineering point of view, advantages over a centrally mounted shock are: No need for the weight and complexity of a braced central cross-member to mount the top of the shock to Much improved access to shock and linkage maintenance Allows for a bigger airbox and more direct airflow into carb From a selling point of view it's novel and different Disadvantages Vulnerability to damage Doesn't contribute to centralisation of mass/weight I don't personally think that the design of the actual linkage is a million miles different from the old Yam TY/TYZ arrangement, the short link just runs direct to the bottom shock mount, obviously dimensions will have been worked on and optimised since those days and shock technology and development has moved on light years which is where the massive improvements will be, but principally it works in much the same way. But it's thinking "outside the box" and has moved things on!

Personally, I think that this increase in the minimum weight limit is more geared to reducing (or cutting out altogether) the use of expensive, exotic materials.Ultimately the aim, I think, is to keep prices down. Face it, let Honda loose with their cheque book and you could have a trials bike that weighed as little as a mountain bike, but at what cost? How much is a 4RT Repsol even now compared to the opposition? I remember the Japanese works GP motocrossers of the late 70's and early eighties. Price and the available materials of the time were no object.The fact that each bike was trashed by the end of the GP was seen as a price worth paying for development and success. But it wasn't sustainable, Who'd buy a production MXer that needed a total rebuild after each meeting, it's expensive enough as it is? So they increase minimum weight limits and manufacturers have to use plain old steel instead of titanium and carbon fibre. They did it in the late eighties and early nineties in 500 GP road racing. Suzuki and Schwantz had a considerable weight and manouverability advantage before. But Suzuki weren't stupid, they used being obliged to add weight to the bike cleverly, bracing the frame to make it stiffer and stronger. Which made it more crash damage resistant and therefore a bit more sustainable. So the rules achieved their aim. Look at the number of current manufacturers in the game - Gasser, Ossa, Sherco, Beta, Jotagas, Scorpa, Montesa/Honda, Tarres off to start something new, Dougie Lampkin involved with Vertigo. How many of those will be left by the end of next year (or get off the ground at all) with prices and therefore sales the way they are? It goes back a bit, but remember the days when the UK Montesa, Bultaco and Ossa importers all sold 1000 bikes a year each. How many do the UK importers even sell between them now? And would there still be a market, say, for a modern mono trials bike with an air-cooled head and barrel? Food for thought.....?

I've used a Sherco or Beta Rev3 tensioner spring from the tensioner to the bar on the swing-arm in the past to assist the radial spring, the radial spring also acts as the brake pedal return spring but they're a bit pathetic, Is the end of the bar cross-drilled to take a split-pin? If so, fit the spring, next, a 6mm washer then secure it all with a split-pin, job done!

Think I'd go with the above. Trials has moved so far away from the mainstream and become SO specialised both in (very expensive) machinery and skills that there are fewer and fewer people to become interested in it and take it up? Which means fewer bike sales (if there can be fewer in the current climate) and ultimately the death of the sport if you pursue the theory all the way to the end. Lots of biker people will watch the indoor and outdoor world championships and wonder at the skills involved in it - but how many will actually be inspired by it to try it, buy a bike and take it up in the sort of numbers that the manufacturers need to make it break even? Personal thought? I think we need a control tyre like so many other branches of motorsport....

That's a good question and I think the answer's yes, they were around 14" (I think). Certainly the whole bike is "jacked up" compared to a MAR. I've got a Trials and MX News from 1980 with a test of the TR77 and they're enthusing about the nearly 14" of ground clearance - and then describing how the UK contracted riders of the time (Tony Calvert etc) were cutting and shutting the steering head angles to try and get them to steer......I think they were being touted as Ossa's second coming..... As Woody says, shock angles moved down and up between the MAR, Mk3 and TR77, a good way to tell is to compare the top shock mounts relative to the side panel mounting tabs; the Mk3 has them adjacent to the lower tabs; on the TR77 they've moved back up to the upper tabs. There's a very useful American website called "Ossa Engineering" with promo pics and quantities by engine and frame number of everything Ossa ever built, TR77 numbers were about 600 in total, I think.

Woody's absolutely spot on with his verdict on the TR77, I've got one myself, and Ossa seemed to think that the holy grail of trials was to increase ground clearance as much as possible and the best way to do it was whack longer shocks and forks on the standard geometry - which gives the centre of gravity of a giraffe. One way to bring it back to MAR geometry (but not for the purists) is fit shorter shocks (13.2"?) and shorten the front fork damper rods by an inch at the bottom, but this requires engineering. From memory if you try to drop the forks too far up through the TR77-type yokes (different to MAR), they foul on the handlebar? A lot of TR77's also ran Motoplat points type ignition rather than the usual Motoplat electronic. Allegedly due to supply difficulties during the throes of the Spanish industry, but the points are the same as Bultaco/Montesa and are available though genuine originals are better than the pattern stuff if you can get them

Did yours come with an ignition flywheel.....?!

He was Jim Sandiford's 200 Montesa rider, being regularly placed in the top 10 in the British Champs in the early 80's then he switched to the Armstrong for 1984, riding the 250 alongside Steve Saunders on the 310/320 I think. He was a tidy rider in his day too.

Hi Amo, re your correct colour of green enquiry, I restored my TR77 using SEAT Kent Verde green, it's not a million miles away from the original shade but is slightly darker than the shade of green on Gonelli plastic mudguards, hope this helps!

Try Bob Wright Motorcycles at Weston-super-mare, he does a lot of Fantic stuff including NOS that he unearths in Italy from time to time, hope this helps!

I fitted a Keith Lynas (www.ossaplanet) supplied-Wiseco piston and it turned my TR77 into a different bike (well sort of, you know what I mean!) Revs quicker and cleaner and sounds a whole lot better mechanically as well, not cheap but I reckon well worth it. I,d enquire for mods with Keith, if anybody would know he would, seems to live and breathe Ossas. Hope this helps!

It's the much heralded but not yet seen 2010 model!

I know its a bit of a distance from you but I've always found the UK's Dellorto importers to be brill at info and parts supply (seem to have everything!), even to the specs/jetting/setup of carbs originally supplied on bikes, they're called Eurocarb in Tilehurst, Reading, www.dellorto.uk , they're usually cheaper than buying the carb parts through the bike's dealer too! Think 240 carb was a 26mm Dellorto PHBL (I stand to be corrected!) hope this helps

Sealey have just started advertising a universal motorcycle flywheel holder in the flyers they put around workshops, looks similar to the genuine Honda one for small mxers, think it was about

Wayne, for fork rechroming try Dynasurf in Cheshire. Their main line of work is resurfacing piston rams on JCB's/Cats etc but they seem to do stanchions as a bit of a sideline, I had some Marzocchis done a couple of years back and it was about

Be careful with the front pipe as the expansion chamber is lined with a layer of sound-absorbent material (read fibreglass wool) behind a metal mesh skin that keeps it all in place, check the u-bend at the front of the pipe to make sure its not coked up also same thing with the outlet to the silencer.......but did it run like this before you rebuilt the engine?!! Chain tensioner spring might be a bit weak or the bush and/or tensioner arm itself worn or even seized up, most things available from Bill Pye at Frankfield Fantic, hope this helps

There was an absolutely MINT Explorer on Ebay a couple of weeks back, in Scotland somewhere (SSDT country from memory), red with silver frame, it didn't sell, asking price was set at

Flat Talon sprocket is part no TR 241 - No of teeth required, Steve Sell at Marlimar-UK has loads of stuff, some NOS, some S/H, try him at steve@marlimar-uk.wannadoo.co.uk or ossa.mar@ntlworld.com, sometimes he takes a while to get back but he's very helpful. Further afield, try Keith Lynas at Ossa planet (website), KLynas@aol.com , what he doesn't know about and have for Ossas isn't worth talking about, loads of NOS and repro parts too, his Wiseco pistons are the mutts nuts, he's in California, parts take about 10 days, postage not much more than UK rates really. There's a Spanish website, Ossa Cels with a lot of stuff on but I've never tried them personally, Hope this helps

On a Sherco the clutch compartment is completely sealed off from the gearbox compartment except for a small passage above the clutch drum. The transmission oil filler fills the clutch compartment initially, then on start-up the primary drive gear on the back of the clutch drum acts as an oil-slinger and throws the oil through into the gearbox via the small passage. In actual use there is very little oil in the primary drive case to lube the gears, I think this is to improve clutch response....but the gearbox breather breathes from the clutch compartment so when that's overfull initially from an oil change sometimes oil gets thrown out of the breather before it's all been thrown into the gearbox....from memory I think 315 Monts used something similar....it may just be finding its own level, mine used to.....hope this helps!