Triumphrat

Savannah Bill

Hello,
I have a 1972 T120 TR6C.
I bought it with a failed primary drive and clutch basket. Seemed like a good idea to upgrade to a belt drive primary, duly purchased from MAP.
My question is: with the bike on the side stand, kicking over to pressurise the oil pump causes oil to leak past the crank bearing and into the primary case. The bike does not have a center stand, but it does not appear to be a problem with the bike upright. I have not road tested as yet.
Thanks for any input.

Webby

Hi Bill,

The post 70 models have a shared crankcase/primary lubrication system. If you look closely you should see 3 small holes about 1mm in diameter in the case next to the crank bearing, I would guess that the oil is coming though these (which is normal) and not though the bearing.
The normal solution when fitting a belt drive is to blank off the holes with some small self tapping screws (or I guess some patent plate rivscrews (or whatever they're called) would do a nice neat job)
Here's a pic of the holes you need to blank off, taken from the inside of the crankcase.

http://www.triumphrat.net/attachment...d-dsc00265.jpg

I hope this helps

Webby

RetroRod

Just adding to young Webby's good advice. Bill, you will also have to refit the LH crankcase bearing seal which is deliberately left out to assist the oil exchange. If you do not fit this, you will continue to have engine oil invade the primary. Good luck with the work. RR

Webby

Well done that man!
Forgot all about the oil seal!

RetroRod

C'mon Webby, that was deliberate to see if I would pick up on it!!

I passed the test, yippee!!! RR

dogtired

Excuse my nooby questions here, but...

Now if I understand this right, the primary cover now becomes an oil free area?

Is the new clutch a "dry" model?
If it isn't, how would it get its oil?

Is it a "toothed" belt?

Is it still tensioned as per before, with the friction pad under the belt, adjusted externally by the bolt? Or does it need no tensioner? And assuming it does need a tensioner... if this is now a dry area, is friction and heat, and subsequent wear on the tensioner belt a problem, or is it solved with using different material on the tensioner, or even an idler wheel?


There would obviously be advantages to a belt drive, otherwise you wouldnt be doing it.
What would be the main reason for installing one of these?

__________________
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Webby

1st Prize!
A slab of XXXX is on it's way he he

Webby

Hi dogtired,
There are various different belt conversions out there. Some use the standard pressure plate and clutch plates, only the basket is replaced. Others have a diaphram type pressure plate. They are all dry clutches, the standard Triumph clutch is also dry, the oil is there to lubricate the primary chain and does no good whatsoever for the clutch plates
I've not had any direct experience of the belt conversions but I understand that they have the following advantages:
Better clutch action
No more stuck or slipping clutches (it's the oil that causes this)
No primary chain adjustment
Less oil leaks (one less joint surface to leak)
Less rotating mass (especially if you use a aluminium basket) (I remember in the movie "Brittown" they weighed up the old and new components and there was something like a 2Kg or maybe more difference)

All the belts I've seen have been the toothed type, as the distance between the crank and the clutch is fixed there is no requirement for a tensioner.
Some shops advertise conversions that can be run in oil, so evicting the need to blank off the holes and add an oil seal (thanks RR ) in the later models, however personally I'm not convinced by this, there was a thread a while back from a guy who's belt had snapped after running it in oil.

I hope this answers some of your questions, as I said I've no direct experience, just some info I've picked up along the way, hopefully someone with real experience should be able to confirm (or disagee ) and add a bit more info

Webby

dogtired

Thanks for the answers Webby.

Cleared a fair bit up for me. Sounds a good thing.

__________________
Can a storm be officially designated as a tornado without touching down at a trailer park?

Savannah Bill

Many thanks to all .
I had previously sealed the three weep holes. The clutch kit was supplied by MAP who have been very helpful. In the install instructions they mention the weep holes. They supply a seal that goes onto the crank, I may have this set to far back on the shaft,
I have ordered a replacement seal, sure to damage the existing one removing it.
There might be too much oil in the sump? It only seems to be a problem when the bike is inclined to the left. could it be draining from the reservoir into the sump after sitting a long time?
I hate to hog all this time. I will keep you all posted.
Best wishes to all for a safe New Year.