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Ossa Tr77


bondy
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My TR77 came with a Motoplat electronic ignition which needed repair so got replaced with the new system.

Ride height is little changed from the MAR which had the upper shock mount at the point where the two frame tubes meet with the lower mounting forward of the rear wheel slot, the 77 has the lower point much further to the rear and the upper mount opposite the top side cover screw so overall there is little difference other than a change to the operating angle of the shock, it is worth remembering that the 77 was forerunner to the Gripper which had angled shocks mounted on raised brackets to bring the shocks within the frame.

The forks which I think are about 31" if set with an 1" or more through the top yoke are again then not too different from the earlier bikes whose fork length was +29"? or more from spindle centre to top of leg.

The TR77 came at a time when suspension developement was taking place in all forms of off road sport,the Comerford Bultaco ridden by Vesty being just one and similar design changes taking place at Montesa, they were all looking to improve the rear suspension so the 77 has to be taken in the context of its time, they are a good bike with strong back up from Marlimar.

Edited by trialsrfun
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Hello guys where is the Engine and frame numbers on the ossa TR77? It's the black frame modle green tank also should the rims have been gold on this modle? They have alloy ones on it cheers bondy.

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Gold rims were fitted to the Verde model tha black frame had alloy ones.

I have measured the forks on my TR77 they are 32" with on mybike 2" through the yokes, a pair of earlier MAR forks are around 29.5".

The 77 has Betor yokes which are parallel and narrower than those on the MAR which have run out.

The MAR top yoke is stepped by a small amount but this pushes the forks down which is the same as having slightly longer fork legs.

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Not yet trialsrfun going looking at it this next week i have seen it i did see it being riden looks and sounds good but ill have to check it over is the a cylinder head steady on these? Just want to know what to look for i gess it's only like any other bike but just wanted to be sure. It's not to bad nice tidy bike.

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  • 2 months later...

hello all i have now got my ossa TR77 nice bike and runs well however there is some things need doing like new sprocket chain. iv'e also bought a new Airfilter as the 1 that was in had seen better days. and i bought a new Exhaust gasket because i took it off to paint it and there is a few bits need patching up on the Exhaust as its blowing i have repacked the rear. am debating weather to buy a new Exhaust butvthis 1 is not in bad shape. but if i was to buy a Exhaust is the rear Wes ok. it needs new rear shocks what is the standard size? i was addviced to get the 360mm? thats about it really dare say ill need somthing else its a nice tidy bike just needs a little TLC oh need new seat foam and cover the old foam had had it the base is good the old cover is pretty good just a bit missing on the Conner but ill buy new. Cheers bond.

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hello anybody know if there should be a spring on the rear brake pedle? the pedle comes back slow. am not sure if the chain tensioner is the correct 1 i will upload a photo it has a big rubber wheel with a spring hooked on a pivot there is somthing missing on the other end off the chain tensionor cheers bondy.

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  • 2 weeks later...

hello anybody know if there should be a spring on the rear brake pedle? the pedle comes back slow. am not sure if the chain tensioner is the correct 1 i will upload a photo it has a big rubber wheel with a spring hooked on a pivot there is somthing missing on the other end off the chain tensionor cheers bondy.

 

Hi there

My TR77 came as a box of bits and it has been SO difficult to work out how some of it goes - as loads of bits were missing, and some bits aren't TR77! I found the brake assembly very confusing, but think I've got it right now (please correct me if I haven't). Its very different to earlier MARs and all the manuals and pics I could find don't look like mine. As such, don't count me as the 'correct' source!

 

Anyway, yes, the brake pedal should be sprung. There are two springs acting upon it - one on the rear brake hub and the other that tensions both the chain tensioner and the brake pedal. This is how I've done mine and it seems correct to me....

 

Brake1.jpg

 

This shows the shaft spring in position. The small hook goes round a pin that goes in the brake shaft, the other end goes under the chain tensioner as shown below:

 

Brake2.jpg

 

I'm pulling the tensioner down, against the spring tension, to show you how mine looks.

 

Below is the spring on the rear hub. Mines rusty, but I put it on to try and work out how it all goes.

 

Brake3.jpg

 

Hope this helps. I found information on this part of the TR77 almost impossible to find, and hope its right....

All the best

Adrian

Edited by t20racerman
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