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bondy

Ossa Tr77

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Hello chaps am thinking off buying a ossa Tr77 iv'e never had 1 before are they ok am a bultaco man but fancy a ossa somthing different to my bultacos.

Edited by bondy

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Hi bondy,

 

If I,m thinking of the correct one that is the all green verde? As rare as hens teeth over here.I think you will need Woodys expertise on how it compares to a Bul or earlier MAR.

 I did,however,just finish my first total rebuild of an Ossa engine(175 stiletto) and I can tell you that the Bul is much,much easier to work on.Every shaft in the trans is shimmed along with the crankshaft.I didn,t pay attention when I pulled mine apart :wall:  so I had to start from scratch and re-shim all of it.

 If you do pull the trigger and buy it let us no and post some pics!

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Hello scot taco yes it is the green 1 and is in good condtion i think it's been serviced iv'e seen it running sound nice. Am hoping i won't need to pull it apart as it's just had main bearings replaced.it would be a big help if woody did tell me what to look for i have only experience with bultaco.

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Hello again the ossa TR77 with the black frame green tank what year was it please? Also what are they like to maintain clutch ect. and is it 1 oil for clutch and gear box? As am used to the bultaco separate oils. This is a 350 but was told it's a 310? also are parts easy to get hold off? The bike is all good as it's been throw i just wanted to get some idea off what am letting my self in for i do love the look off the bike. Is as a nice green fiber tank witch as not got fuel in it so i was thinking off may be buying another tank is there such thing as a plastic tank for this modle? I have seen the alloy ones but i dont want to put a nice new shinny tank on to ride so id be looking at a second hand tank. Happy new year bondy.

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HI bondy,

 

I can answer a few of your questions.

 

I think it,s a 1979,but could be wrong on that.

 

It is a 310

 

The gearbox and clutch share the same oil,not as easy to fill as a Bul.

 

Not sure about the clutch.I have one that has a nice clutch and one that I just can,t get to work well on so it must be operator error.

 

I have never seen a plastic tank for one.

 

Try these two sites for info. http://ossa.2y.net/index.html  http://www.ossaworld.com/

 

Cheers, Scott

 

Edited by scot taco

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Hi Bondy,

The black framed OSSA TR77 is essentially the same bike as the all green Verde model which was the last version.

The clutch if fitted with new plates from Steve at Marlimar will operate very well with a good feel and light action, suspension (both ends) works very well on my own TR77 Verde, the footrests in my opinion are better lowered.

Overall I would rate the TR77 as equal to a Bultaco.

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Hello scot and trialsrfun that you for you replys this gives me a good idea off the bike the bike as fare as i know dose not need and work doning as it's had the work done to make it operate as it should. Another thing iwanted to ask is there a electronic ignition available for this modle? Thanks scot for the links.bondy

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The 77 has a Motoplat electronic ignition ftted when new but if that needs repair Steve at Marlimar supplies a digital ignition that is easy to fit and works superbly well. I have one on my bike which along with a Motocarb 26mm Mikuni makes for a good performance.

Edited by trialsrfun
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Hi Bondy, I've got an all- green TR77, I believe that it's the 1978 model, I think they went to black frames in 1979, Woody should be able to confirm if he posts.

 

A lot of them came with Motoplat points ignitions, mine has, I was told that Motoplat were struggling at the time and were basically sending out anything that they could manage? Mine's never given any trouble though. Steve Sell at Marlimar is your man for virtually anything. If you're looking for an Ossa tank (alloy) in any sort of reasonable condition, be prepared to dig deep....

 

In the name of increasing ground clearance (I think), Ossa fitted longer shocks and dropped the fork legs down through the yokes (or even fitted longer legs?) on the TR, all with the standard geometry, I personally think my Mk 1 MAR handles a lot better with a lower centre of gravity.

 

If you check out the US website "Ossa Engineering" they've got a full gallery and specs of everything Ossa ever built, their boss man Steve Levi used to be the boss of the US Ossa importers and is very helpful with a range of Ossa products too.

 

Hope this helps!

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Looks like most of your questions have been answered but what do you really want to know in the context of are they alright?  It's subjective and personal opinion.

 

Yes they're a decent bike but not as good as the Bultaco of the same era as they had virtually no development from the original MAR, just longer travel suspension with angled rear and longer forks, revised porting on the cylinder which made them a bit quicker on pick up as the MAR has a fairly docile power delivery. Longer front pipe and one of the most ridiculous rear silencers ever stuck on a trials bike. Green bikes usually had points, Ossa went back to electronic on the Grippers. The green bike with the black frame was 1977, hence TR77, the green frame was introduced in 79, TR77 Verde and was the same bike apart from gold rims and all green frame and guards.

 

The 350, usually called 310 is actually 302cc. I've never ridden a 350 TR77 so no idea what they go like and never ridden a 250 TR77 in sections, so can't really compare with the power delivery of the earlier bikes. I've got a TR77 350 cylinder and it is slightly different porting from my MK2 350 cylinder but how that translates to performance I've no idea. I had a MK3 MAR years ago for a short while and it felt too high with the long travel suspension and needed the forks pulled up through the yokes to make it steer like the MK2 which is a very good handling bike. Maybe it could have done with slightly shorter rear shocks too but Ossa actually moved the shock top mount on the TR77 which probably had the same affect.

 

It's all academic now as when the bikes were new, top centre and national riders would have needed the bike to be as competitive as possible against the bikes from other manufacturers. Nowadays, the sections ridden in classic trials are nowhere near as hard as sections from centre and national trials back then and the bike, even in standard chopper form, is more than capable of handling classic events. If your not riding it in trials it matters even less.

 

Maintenance is no different from other bikes. Yes it has the same oil for clutch and gearbox, 800 - 900cc, but can't see why that is an issue, the Bultaco and Montesa are the only bikes I can think of off the top of my head that have seperate gear and clutch oil. Points maintenance is no different from other bikes but if it has electronic it needs none, just check inside the casing now and again to make sure there is no water in there as the timing cover isn't a brilliant fit in front of the drive sprocket. A useful mod is to move the wires from the stator from exiting through the bottom of the case to exit through the front of the case. There are articles on here somewhere describing how to do this, if not already done. When the wires exit from the bottom they are bent 90 degrees and can get trapped between the sumpguard and engine if the sump has had a good battering which can split the insulation enough to short out the wire and kill the spark. Same can also happen if the insulation has gone hard / brittle over the years.and cracked.

 

The rear brake plate has a flange / slot in it to locate on a lug on the swingarm instead of a torque arm. The alloy of the brake plate is very brittle and if there is any chatter in the fit of the slot on the lug it is possible to break the top flange of the slot clean off if the rear brake is applied hard, meaning you have no rear brake as the plate is no longer fixed in place and free to rotate (I've done it on 3 bikes over the years) It's probably beneficial to pack shims to remove any slack if it's possible to do so and eliminate any chatter from the brake plate.

 

Lastly, all UK bikes had alloy tanks so if the one you're looking at has fibreglass it's probably a later import, unless someone has retro fitted a glass tank. The black framed TR77 had the same alloy tank as the earlier bikes but the green framed bike had a re-shaped tank with an extended front

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For got to ask what tank will fit mt ossa tr77? Iv'e seen 1 from sammy miller dont really want to pay that much i really wanted a used 1 i could may be tart up cheers bondy. P.s how do i get in contact with steve sell dose he have a website?

Edited by bondy

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