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!)

 

 

 

 

 

It's a standard size bearing so easy to source a new one. Once you have it removed, you'll find the number stamped on it (as with the clutch side roller)

I can't remember what they are as it's a while since I did mine

 

The crankcase has a hole in it as the bearing outer case is closed at one end, so it seals the hole when in situ.  To remove just warm the casing and tap it out with a drift from the outside inwards

 

 

Hello Adrian, good to see you're finally sorting the OSSA.

Will you be at Pembrey over Easter?

Hello Adrian, good to see you're finally sorting the OSSA.

Will you be at Pembrey over Easter?

 

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.

hello guys sory to but in i also am new to ossa and have just bought same model ossa TR77 runs well just needs a few jobs doing to it. iv'e noticed a very small drip off oil comming from the gear leaver i gess there's a oil seal? if so does the case need to be taken off to replace it? cheers guys sory to but in on your topic hope you get the Engine sorted bond.

A good source of info'...

http://www.carlsalter.com/classic-bike-service-manuals.asp

www.carlsalter.com

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

hello guys  as you know I just bought a tr77 alto it runs good am just thinking are they easy to rebuild any tips am use to bultaco I heard the ossa as shim inside alot more then bultaco any body done 1

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.  :-)