t20racerman

Hi all Anyone know what the correct steering head angle should be on a TR77 MAR? Thanks Adrian

Can't you get the original welded up?

I'm no 'expert' but I've been riding and working on bikes for nearly 40 years. The TR77 engine is different to most I've worked on before, but an engine is an engine.... The primary chain drive shaft that fits on the crank is almost impossible to remove - I had to have a huge, strong special puller made after the first two broke - you can't remove it without one. There are shims inside, and at first it all seems quite complicated. To be honest, I found it quite intimidating, but once you've studied it, played with it, and got your head round it, its just like any other engine. If you know what you are doing, no problem! The engine was as it originally was many years ago when I got the bike (in bits) and everything was pretty much shagged. However, everything you need is available, and you can get shims from the internet (most sizes) or laser cut by good friends if you know the right people. The new centre gasket I have is about 0.2mm thicker than the original one, and I've replaced all the bearings and had the crank rebuilt too. As such, I've had to add shims to the crank and gearbox shafts. Its fiddly to measure up, and for best results you'll need a dial gauge, but I think I've got it right - we'll see soon! If you live near me, happy to meet up. I'll be building up my engine the week after this one as I have a week off then. :-)

I need to add about 0.2- 0.3mm so I'll add them all to the LH side which should keep everything pretty much the same as it was. I will check it selects all the gears though as you suggest, and have now decided to NOT use gasket glue.

Hi all My Clymer manual for the Ossa MAR says to use a new gasket on the crankcase halves, grease the surfaces and to NOT use any gasket glue. How well does this seal? What are your experiences? The gasket set I got from 'In Motion' seems very high quality so I can see why, and the surfaces are pretty good too. However, with a long history of working on leaking Brit bikes (and old Jap classics) I thought I'd ask.... Had to shim up the crank and gearbox too as the new gasket is about .25mm thicker than the old one. Fiddly, but it has to be done.

I have some ACF30 and will use that. I don't like paint if it isn't needed. Re Jap alloy, my '67 T20 Suzuki alloy furs up if a cloud passes overhead! No wonder they lacquered it as standard :-( My BSA A10 casings though, polish like mirrors if I buff them once a year... Re Vapour blasting - it wasn't cheap. I took in the head, barrel and cases. All were painted and had sat covered in ***** for 15+ years. They soaked them all in paint stripper, then washed in solvent, then blasted them to get all the crap off. I was quoted 60 quid plus VAT for the job on the assumption it would take an hour. It took nearly double that, and the woman doing the bits was very concerned to get it done really well. The company was West Country Windings (based in Essex between Harlow and Bishop's Stortford) who can be found here: http://www.westcountrywindings.co.uk/ This company eat, sleep and think bikes. Happy to support them. :-)

Thanks. I know some early Jap alloy was so prone to corrosion that it was painted or lacquered, but the Ossa casings look much better than this. Saves me buying some paint... :-)

Hi all Presently restoring a TR77 that has been in bits for 15+ years. The crankcases were painted a silvery colour and I had this all vapour blasted off today. The casings underneath look superb, and the alloy (at this time) shows no signs of corrosion. As they are sand-cast, I assume that the alloy is pretty good quality. Were they painted originally other than on the green TR77's? I'd rather leave the alloy bare if it doesn't corrode. Was there any reason for painting them? I'd appreciate your experiences with unpainted cases Thanks Adrian

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

Hi there There is an 'O' ring in the casing where the shaft comes out. The only way to replace this is to remove the casing. Hope this helps. Adrian

I'd love to show you my Ossa TR77 in action... but sadly it is taking me a lot of time to restore the thing. It came as a box of bits with the assurance "its all there mate" and "it was running fine when I stripped it" but of course, there is loads missing and everything I DO have is completely worn/trashed/bent/cracked etc. To be fair, it was given me for nothing and once done it will be like a brand new bike. Here it is at the moment...

Hi Spen No, off on a family holiday instead. The TZ350 is nearly ready to go but the T20 needs stripping and the gearbox fixing. Unfortunately this Ossa and my KTM have bled my bike funds dry. Will be out later in the season, but probably not with the CRMC. Fancy a change.

I'm restoring a TR77 from a box of bits and after cleaning up the crankcases I found cracks on both sides where the cylinder studs go in. Is this a common problem or have the studs been tightened up by a Gorilla with a 10 foot long wrench? Work to do :-(

Hi all I'm new to the forum (and Ossa's) and hope you can help. I'm restoring a TR77 that I got in pieces 15 years ago and am finally getting it together. The engine is stripped, the crank rebuilt, and the main bearings and other bearings in the casing seem easy enough to source, but I'm puzzled at the blind needle roller pictured below. Is this an open-at-both-ends bearing fitted up against a blocking end piece, or is it a one piece closed-at-one-end needle roller bearing? Also, does anyone know what number bearing it is so that I can buy one from somewhere? Is it easy to remove? Any other tips or comments you have would be much appreciated Thanks Adrian (PS Hi Spen - I noticed that you are a forum member!)