1959 Triumph 5TA Clutch

[twolitre]

The clutch on my 5TA is very heavy. Twice the nipple has pulled off the handlebar end of the cable. The second time, embarrasingly. just as I was about to embark on the ferry returning from the Manx GP.

I can find no cause. In my ownership the clutch has always had a tendency to slip when kick-starting it and relieving the springs tension does little for the "heaviness" and just makes the slip bad enough to detect on acceleration etc. I replaced the (4) springs with no improvement. The cable is routed as sympathetically as possible avoiding sharp bends, kinks or trapping and the lever in the gearbox housing is free and smooth in operation off the machine. The clutch plates are running true with no wobble. The chaincase has the correct oil. Once again Mr Hayne's "bible" has let me down with almost no mention of clutch operation, though I did find that two different push rod lengths are used/available. I don't know which is fitted to mine, nor what effect the wrong one might have. The one I have is adjusted to the correct end clearance.

Is this "heaviness" typical of unit construction? It is certainly very different from my pre-unit 5T, which I can operate with one finger.

Any advice or opinions gratefully received.
Thanks, Jim.

[Goldie]

At one time back along, I fitted Norton Domminator clutch springs in place of the Triumph ones on my Triton, because it was suffering from clutch slip.

It did the trick, but the clutch was a little heavier to operate.

Could it be that someone in the past has fitted heavier springs?

[twolitre]

Hi Goldie, I did replace the springs with new bought from Sheffield Classic Motorcycles (Bantam John), because of the tendency to slip. I presume they are correct, but have no way of checking. Certainly the brass spring caps are only just level with the end of the threads. Do you think springs of a lower compression rating might work? I cannot make up my mind.

Also, the Haynes Manual I picked up from the library shows only three spring clutch illustrations. Mine is 4 spring. Do I have the wrong clutch assembly fitted? I do not have the proper handbook.

Thanks for your reply, Jim.

By the way:- A tribute to Carol Nash insurance might be appropriate here. After a struggle to get the bike on the ferry, I rang Carol Nash Breakdown. They had a purpose built van waiting on the dockside in Liverpool with an extremely helpful, polite and pleasant driver who loaded my bike and transported me and it home to Chesterfield with no drama. I cannot praise the service highly enough.

[Goldie]

Have you tried fitting a new clutch cable, or checked the old inner cable for freedom of movement within the outer casing.

Could it be that it is seizing up due to lack of lubrication.

Take cable off bike and test cable by putting nipple in vice and moving outer cable to and fro.

It could be a lack of oil/lubrication. which does not help especially when there are bends in the cable however slight they are.

[twolitre]

The cable was replaced with a lubricated new one on return from the Isle of Man at the end of August. Now being the third one in less than 3 years. One thing I did not mention was that a soderless nipple was tried on the dockside at Douglas. It would not hold against the resistance of the clutch. I could cope with the heavy operation, but I know from experience that the new cable will fail before long. It would be less worrying if replacing the cable did not require removal of the gearbox outer casing.

[L.A.B.]

Various changes were made to the lifter mechanism, so are you sure the correct set of lifter parts are fitted?

[twolitre]

Various changes were made to the lifter mechanism, so are you sure the correct set of lifter parts are fitted?

Can you enlarge on that L.A.B.? How can I identify wrong (or right) mechanisms? I am considering removing the gearbox outer casing (again) without altering any adjustments to see if the operating lever is at right angles to the lie of the inner cable as it obviously should be. My 5TA is pre-primary chain adjuster. Do you think that might be significant? Were other changes/mods. made at the same time, because the crankcase was obviously modified to accept the adjuster (different primary chaincase gasket)?

[L.A.B.]

How can I identify wrong (or right) mechanisms?

Checking various years of 350/500 parts books it is apparent that certain changes were made to the lifter mechanism arm. and the method of cable attachment was changed, also the later versions had a ball ramp lifter instead of the quick thread. There were various detail differences between the 3TA, 5TA and T100 clutch assemblies, such as 4, 5 and 6 friction plates, different length screwed pins and clutch centres, 3 and 4 spring clutches, so you may have some mismatched clutch parts, as there shouldn't be any reason for the clutch action to be so heavy?    

[twolitre]

Thank you for going to so much trouble and doing the research L.A.B.
I have got hold of a No4 Instruction Manual marked "up to Engine No. H29773", but the Primary chain diagram shows an adjuster, so the manual is obviously more recent than my bike, though the thread operated clutch mechanism looks the same.

My engine and frame number match as 5TA H 7776, so there is no jiggery pokery there. Dare I beg more of your indulgence to check my engine number against your parts lists?

Thanks, just in case, Jim.

[L.A.B.]

I have got hold of a No4 Instruction Manual marked "up to Engine No. H29773", but the Primary chain diagram shows an adjuster, so the manual is obviously more recent than my bike, though the thread operated clutch mechanism looks the same.

My engine and frame number match as 5TA H 7776, so there is no jiggery pokery there. Dare I beg more of your indulgence to check my engine number against your parts lists?

Comparing the '59 No.2 parts list (from Eng. H 5485) with the '61 No.4 list, (H 18612) No.2 gives the early lever and worm as part T1484. No.4 lists it as T1459, and T1638 after Eng. No. H 25252.

The No.2 parts book shows the '59 5TA had the same 4 friction plate clutch as the 3TA. No.4 list shows the 500 models had the 5 friction plate clutch by then, and only the 3TA continued to use the 4 friction plate clutch, however the 5TA continued to use the same T1456 clutch pushrod as the 3TA. The T100 models used a different T1574 pushrod.              

[twolitre]

Thanks very much for all that L.A.B.  I'll try to get my head round all that, but the weather here is, like everywhere else, pretty abominable. I could even do with a sled and huskies to get to my garage. I think I will postpone further investigation until the weather improves.

Jim.

[cardan]

"I think I will postpone further investigation until the weather improves."

Reading this from Adelaide (Australia) I can't resist chiming in regarding our weather at the moment. So far this week, max temps have been 31, 32 34, 36 (celsius, not farenheit!). Nice enough. Today is heading for 39, then the next three days are forecast 41, 41, 41. For old fashioned folk, 41C is about 106F. So, if it's any comfort, work in the shed out here is also postponed until the weather improves!

All the best for the New Year,

Leon

[twolitre]

Sorry Cardan, I tend to sometimes forget that lots of Forum Members do not live in Britain. I was almost prompted to ask for the loan of your shed to sort things out, but then I saw the temperature. I don't think the huskies could stand it!

Happy New Year to all in Oz (which includes my niece somewhere near Darwin).

Jim.