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khristi

Beta TR33 1986 Service

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Hello, I'm new here and I have just purchased a Beta TR33, with the 239 cc engine, from 1986. The bike has been stored in a garage for the last five years and we didn't try to start it since the kick start lever was removed. The engine went around fine and compression seemed very good though. I don't even have the bike home yet but when checking it at the sellers place I noticed a few things:

1. The rear suspension had quite slow return. The spring seemed fine but the damper probably needs service. How servicable are those? Nitrogen filled or just oil?

2. The front break needed quite some pumping to build pressure. I didn't see any leaks so I guess this is because the bike has not been used for the last five years. What do you think?

3. The right fork had a small leak. Is there any seals to get or do I have to go for some generic?

4. The clutch didn't disengage the drive entirely but had no noticeable slack either? Ideas? Time for new discs?

I will probably have more questions once the bike is in my garage, thanks for now.

Edited by khristi

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Hello khristi, I can only comment on Q4 about the clutch and even then I'm comparing it to the '87 TR 34 that I had new back in the day, but it may give some insight into the woeful clutch action that those early Beta's had.

I bought a new 1987 TR 34 from Beta direct from Italy back in the day because we had no importer in Oz at that time, it had a horrible dragging clutch which couldn't be fixed with different oils .Me and my trials riding buddies tried to fix it by shortening the alloy actuating arm on top of the case to increase plate separation, this helped but gave me a very heavy clutch lever pull, then I went and got some softer springs made up which helped the action but gave me a clutch that slipped. From memory I think we even attempted to clean out the crud from between the friction pads and file off any sharp edges on the steel plates, basically we tried every thing we could think of and it was always an ordinary clutch.

After a few "telexes" to Florence (no emails back then), I finally got a little packet of improvement parts the main one from memory being the toothed actuating push rod from down inside the clutch cover, I never got to try them out as I sold the bike with those parts still in the packet. I reckon your TR 33 has the same crappy clutch that my TR 34 had.

I should add that the next time I rode a Beta was the '89 stripey or 'zebra' as we called them here, and it's clutch action was very good compared to my TR 34.

So in essence, if you can't improve you clutch with the "Beta clutch fix" and different oils, than see if the '89 clutch parts will retro-fit your TR 33. Hope this long winded story helps?

PS: There was a '88 model between mine and the stripey, it was known as the TR 34 'Replica'. This is the model that those clutch parts would have come from, but as stated I never fitted them so cannot comment. The '89 stripey did have a pretty good clutch for back in the day.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited by fourex
PS added.

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Thank you for your answer. I have ordered a set of new discs and will prepare them according to the guide on this forum. Maybe the basket will need some polishing as well. I'll look in to this toothed rod thing you mention and see what fits between the models/years.

I found new fork seals on ebay. And I guess since there's no leak in the front brake it's probably just a cleanup+new fluid+air purge that's needed.

Main concern now is how to service the rear shock and linkage for a quicker return/rebound.

IMG_0334.JPG

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Ok, the linkage is just fine and the spring is good as well. But the shock is very stiff, I can hardly push it together by hand (spring removed). It does not serm to be a serviceable shock, there is no way I can disassemble this. Anyone knows?

Edited by khristi

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 The shock was not meant to be serviceable. I have a TR33 that I ride in our vintage events. As said above not near as good as the `89 TR34 I rode as new. Better off to just ride it as is or find something newer. It is not going to be much of  a bike to learn trials on.

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I'm not giving up on this one yet. My plan is to ride it like a mix between "slow enduro" and "free in the woods trial", like a cheap version of an Ossa Explorer or similar. I'll hardly be riding any challanging, pure trials with it.

The brake is now ok after adding new fluid and purging air.

The clutch is ok. The friction discs and the plain discs were almost "glued" together by old sticky oil. Took it apart and cleaned it up and it now engages and releases as supposed (I suppose). Couldn't find a torque value for the clutch spring bolts so I used 12 Nm. Anyone knows?

I have new seals for the forks but the dust caps seem unavalable. I guess I just have to use the old ones which seem fine and maybe use neoprene protectors in addition.

The rear shock are now in parts. Small pieces of the internal "punch through" rubber had came loose and were jammed in the valve. I accidently spilled most of the oil when I took it apart and I don't know how much oil to add. There is a separate chamber in the tube, I dont know if it's nitrogen filled, air filled or just spring loaded. There is no schrader valve or similar to refill it with (if air or nitrogen) but it's very springy and if gas filled it doesn't leak. Should the oil chamber be entirely filled when gas chamber is fully compressed? There does not seem to be a spec avalable for this shock so whats's generally the idea? When looking on rebuild videos of shocks with external gas bladder they seem to fill fully with oil before adding nitrogen.

IMG_0364.JPG

IMG_0363.JPG

Edited by khristi

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Hi khristi,

Regarding the fork seals / dust covers.  The original covers aren't available but new versions with outer metal spring are. I bought mine from Steve goode motorcycles, Dave renham (in motion) sells them too. By the way, check you get the right fork seals. My TR34 has 2 x 10mm deep seals per fork leg, not 7mm ones.

I can't help with your other questions,  but I have one for you. Is the white plastic bit the main cap, or just a pushed on cover ?

Your rear shock looks like the same one on my TR34 (made by corte cosso i think, has a black aduster on the top).
My shock works fine, but I want to get it replated, so need to strip it.

Hope that helps. 

Cheers, John. 

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The white plastic is just the outer dust cap. Inside it there's a smaller o-ring type dust cap toward the stem. The main cap is partly visible inside the dust cap.

I made a compression tool to push down the main cap 2-3 mm until the circlip could be removed. When releasing the compression tool the main cap popped out with most of the oil and the valve stack came all the way up to the second circlip. I drilled a hole almost all the way towards the upper ring, check position so the schrader valve wont interfer with the frame/airbox/saddle. You could just drill and release pressure first of all, then you wont need a homemade compression tool.

I threaded the hole and fitted a schrader and put some pressure on it to push out the gas piston. Be very careful at this stage and aim inside a bucket or something and wear protective goggles and other PPE, ideal would be to push it out with water or another uncompressable media. Clean out the swarf from the drilling and tapping otherwise the gas seal will get ruined I guess.

I have just put all my parts together and waiting for the loctite to cure. Will hopefully finalize later this week and add som photos.

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Thanks for the reply.

I removed the dust cover but couldn't compress the cap to get the circlip out. I took it to a local suspension specialist who said it's not intended to be rebuildable, and he said adding a valve to the body is not usually very successful. I'm therefore just having the outside replated with all the shaft etc still in place. I will post some pics when I get it back next week.

Cheers,  John.

P.'s.  I am rebuilding a tr32 too, which is essentially the same as your tr33 but no front disc brake. 

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Mine seem to hold up. At least is feels better than before and I cant't see any leaks. Haven't really ridden much because I'm waiting for new seals for the front fork. For the moment I've only filled it with about 12 Bar of air since i don't have a regulator in the 12-15 Bar region for my argon bottle (Tig weld protection gas).

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