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Re: clutch slips
desco #824236 09/19/20 9:07 pm
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Re: clutch slips
splash #824240 09/19/20 9:48 pm
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Call me old fashioned but I prefer a book. I can tell what parts of the book I look at most by the grease on the edge of the pages.

Last edited by desco; 09/19/20 9:57 pm. Reason: addition

1968 T120R
1972 T120RV
Any advice given is without a warranty expressed or implied.
Re: clutch slips
splash #824242 09/19/20 10:14 pm
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I have the PDF of that one LAB and find it useful for the most part but it's missing the clutch exploded view "with names" of the parts. I tried a parts PDF file and the numbers by the parts are little black blobs. I used the one on the MAP site.

Desco, I like the book too. I still use the Hayne's book I have just because it's physically on hand and yeah, my favorite pages are full of grease as well. I haven't looked at it for this problem but it is with the bike at a friends house down the street. He has all the tools so he lets me keep it there when I need to wrench on it.
I think I know what you are talking about back there. Looking into it....

Last edited by splash; 09/19/20 10:17 pm.

1970 Triumph tiger owner
Re: clutch slips
splash #824251 09/19/20 11:45 pm
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Hi Splash, I see a huge problem that is causing back plate to fall behind hub. As did LAB.

I will say without question this is bad. Back side screws coming loose is probably the cause. Those screws generally need blue loctie & I always stake the screw head at slot as well. But... excess wear of spider back side will cause similar condition.

Your next step is to remove the cush hub & inspect back side.

Might find other things wrong behind also. I'd expect the screws to be damaged & very likely the screw threads in spider to be wallowed out as well. But tear down & inspection will show what's needed. Should you need spider, I'd get a new LF Harris hub. Not cheap. Get the later design with hex bolts instead of flat head screws. Much stronger in my mind. They are interchangeable. I believe mid production or so the '70 650 got the later hub with hex bolts from new at factory.

If we were together with all the parts this would make sense. Looking at exploded view it's hard to tell what holds what if you aren't familiar with what's going on.

The small hub with taper goes onto main shaft with key. This hub has external spline. The spider has internal spline to match. So the spider slides over the hub. The fat washer under main shaft nut is just right size to press against spline of spider. Close exam when you take nut & washer off will show this. The end of the tapered hub is slightly shorter. So the spider is pinched tight against shoulder on tapered hub. At the same time the nut pushes taper of hub tight to main shaft.

So, the spider is fixed tightly to main shaft via the splines & tapered hub.

What about the drum where clutch plates ride? The spider has 3 legs or arms if you will. The rubbers go against them. The drum has 3 large protrusions where the clutch springs will be. So the rubbers press on them. So clutch plates rotate drum, pushing rubbers, which push spider arms, turning spider & main shaft.

So the side plates of cush hub secured by the 3 screws ride on shoulder on each end of spider. You can see in photo outer plate has moved to left of machine & not longer is riding on shoulder of spider.

The end plates each side screwed to spider is what holds the drum centered over spider. So it looks like the back side screws may have come out.

I can't explain why, but when the drum has too much play on sides of spiders the force on clutch tends to cant the drum, wanting to separate clutch plates & slip. Normal bad wear on spider & back plate will allow similar to happen.

From what you say about ongoing problem with steel plate falling off back & getting stuck I wonder If the back plate may not have been perfectly seated for some reason. I've had a fair amount of these apart. Expanded cush rubbers can simulate a tight feeling plate when it's actually not seated yet. Accidently using T150 small rubbers will cause this. They look similar.

None the less next step is remove cush hub. If not too tight on spline you can work it out, leaving tapered hub, basket in place with chain in place as well.

On the other had I'd pull basket so you can inspect thrust washer & back side of basket. It could have taken damage as it's position relies on a stable back plate. Cush hub back plate is the outer thrust surface for the basket.

Please photo what you find. The photo you just posted solved the mystery. Now we need to see why it went wrong & what is best plan for repairs.
Don


1973 Tiger 750
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Re: clutch slips
splash #824254 09/20/20 12:04 am
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i thought you bought a new clutch hub ... not to long ago ?

" Official " 1970 Triumph 120 parts catalog :
https://partsbooks.britishonly.com/partsbooks/20-10221C.pdf
clutch is on page 32 ( page 40 of pdf. )

Re: clutch slips
TR7RVMan #824268 09/20/20 5:02 am
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Originally Posted by TR7RVMan
I believe mid production or so the '70 650 got the later hub with hex bolts from new at factory.

Later '71 production (according to the '71 parts book)..

https://jrcengineering.com/wp-content/uploads/2015/09/T120-TR6-1971.pdf
pdf p.35.

Re: clutch slips
splash #824273 09/20/20 10:29 am
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Thanks Quinten! I'll save that to my files.

Hey Don, page 40 of the parts manual Quinten posted has numbers on the parts. It may be easy to use just the numbers because I can't be sure to understand what you mean when you write cush hub (6?). When I did the complete rebuild I replaced parts (4) rollers, (3) thrush washer, and (10&11) rubbers. The new rubbers were very difficult to install.
Last time this happen the clutch push rod wasn't stuck in the main shaft like it is this time and I remember putting blue loc tite on the screws (8) both sides of (6) centre. The backside screws were loose causing the plates to fall like they are now if I remember correctly. Back then the (12) outer plate was also not flush with (9) spider as in my picture I posted. I wonder if I put the rubbers in correct or if they sent me the wrong rubbers now if this is a continuing problem. The bike is still like it is in the picture, I haven't gone any further with it yet. I may get into it more tomorrow if some spare time and will sure take more pictures.

thanks for all the feed back guys.
Yes, a bolt would be much better than a flathead screw here.

Last edited by splash; 09/20/20 10:41 am.

1970 Triumph tiger owner
Re: clutch slips
splash #824290 09/20/20 5:29 pm
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Hi Splash,

Firstly, the un-removable clutch pushrod.
It has almost certainly mushroomed significantly at its timing side (gearbox) end.

The gearbox mainshaft has an internal bore ID from the gearbox end much larger than the OD of the pushrod. This large bore runs for most of the length of the mainshaft, but not all the way to the clutch end.
There is a brass or bronze collar a little way in from the gearbox end, which loosely gives the pushrod some centering support in this what would otherwise be a very slack fit in that end of the mainshaft.

The amount of mushrooming at the gearbox end of the pushrod is evidently minor enough to pass through that (probably worn) collar.

However, the clutch end of the mainshaft has a smaller ID, only a little more than the OD of the rod. This smaller ID only penetrates a few inches into the mainshaft from the clutch end.
Not only does this smaller ID provide centering support to that end of the rod without needing a collar (a minor point), crucially it maximises the strength of the mainshaft where it extends beyond the gearbox main bearing (there is a long overhang here which carries the loads of the gearbox sprocket and clutch).

I’m pretty sure the mushroomed end is catching on that step in the ID of the mainshaft, and there is little chance of pulling the rod out that way.
You must take the gearbox cover off and try removing the rod from that side.
Your pic is poorly focussed on the clutch end of the rod, but it does appear that there may be slight mushrooming there as well. If so, it may be necessary to file the mushrooming off the clutch end, or just cut the end off, as I suspect a new rod is desirable anyway.

It is unusual to find mushrooming at one or both ends to such a degree with a correct clutch assembly and adjustment. For the most part, the rod spins with the mainshaft and clutch centre in normal running, so if rod free play gradually reduced (for whatever reason) the first frictional heating would be at the rod contact with the lifter thrust button in the gearbox cover. Expect to see damage to this component.

The second part is why, and I suspect this is linked to the other issue that has come to light. Don and LAB have identified a clear clue from your clutch pic (the gap between the outer shock absorber plate and the collar of the spider (that plate should be around the spider collar).
As they have surmised, this can only be because the shock absorber is coming apart, in that the 3 screws holding the backplate to the drum have been unscrewing.
This will allow the main body of the absorber to gradually move away from the gearbox (and will have made a shambles of the normally tight control of the spider within the end plates). As Don has said, this can produce dragging/slipping issues alone.

However, when the back screws have unwound sufficiently, and the outer absorber drum has moved correspondingly away from its designed position, the pressure plate will no longer be able to close properly against the clutch plates. This is when serious clutch slip will take hold.

On the way to this situation, the chainwheel will be allowed more freedom to wobble about (it is usually confined between the hub/thrust washer and outer rim of absorber), though I would expect this to result in drag rather than slip.

I would suspect that you’ve had clutch slip for some time (its not always obvious), possibly with an over-tight pushrod adjustment. Even if this was not originally the case, the self-disassembly of the absorber has resulted in this situation coming to a head.

If you have un-noticed clutch slip going on, it will wear the friction surfaces prematurely (as they are under load at the time), the pushrod clearance will reduce (eventually to zero), then the pushrod and associated bits overheat causing mushrooming.

Why would your backplate screws loosen? You said that you found it difficult to get the new rubbers in, maybe that is a clue? Presumably you inserted them from that back side? In which case you didn’t need to remove the front plate?
Without a couple of simple tools it is an almost impossible task to insert the rubbers properly and fully, such that they exert a neutral force in their housings. You can try pushing a bit of rubber at one end, without ever getting the rubber at the other fully where it needs to be.

To do this, I remove the front plate. Loosening or tightening those screws can be a challenge in itself. The method I use is to clamp the hub in a vice, with a good fitting screwdriver bit, then turn the bit with a spanner (it can’t escape the slot this way).

To install new rubbers, put the splined clutch centre in the vice (carefully not to break the flange), place the absorber onto it, place the large rubbers, then use a C spanner or clutch locking tool to compress the rubbers, creating free space to intall the smaller rubbers. Put a little grease or oil on the rubbers first, so they can find their natural fit.
If you’re gonna use loctite on the screws, the holes need to be thoroughly de-greased first, otherwise the loctite is useless. Better as Don says to stake next to the screw slots.

As mentioned, you may have shot screws and/or screw holes, as the spider was distanced from the back plate you may be lucky, won’t know till you look.

Re: clutch slips
splash #824343 09/21/20 12:11 pm
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Originally Posted by splash

This photo shows a real mess. You've found the cause of the slip, but what was the cause of the clutch centre coming apart? If the spider happened to be extremely badly worn, this could happen, but the wear really would be extreme to allow movement on this scale. Otherwise, the screws that fasten the outer plate on the centre to the rear plate must have come undone - completely undone by the look of it. Can you put a screwdriver in the heads and turn them easily? It looks as if the hub nut isn't a locknut too. It mat not have come undone yet bit if it isn't a locknut, it's another problem waiting to happen.

The pushrod must be mushroomed at the right hand end, as I suggested some posts back. I suggest you need a number of items: (a) a new complete clutch centre (b) a new clutch pushrod and possibly mainshaft bushes (c) a proper workshop manual which covers your actual model and year (I say this because I thought - apparently wrongly - that your bike was an oil-in-frame model, but the photo is of a pre-OIF frame (off the top of my head I can;t recall why I thought your was an OIF bike, I may have imagined this).

I'd also advise checking everything else in the primary case very carefully for wear and / or damage due to having been assembled incorrectly.


If anything other than a blank space is visible here, something's wrong.
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Re: clutch slips
Tigernuts #824346 09/21/20 12:56 pm
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Originally Posted by Tigernuts
This photo shows a real mess. You've found the cause of the slip, but what was the cause of the clutch centre coming apart? If the spider happened to be extremely badly worn, this could happen, but the wear really would be extreme to allow movement on this scale. Otherwise, the screws that fasten the outer plate on the centre to the rear plate must have come undone - completely undone by the look of it. Can you put a screwdriver in the heads and turn them easily?

The inner and outer plates are secured by three short countersunk screws each, so six screws in total, not three long screws.
https://www.classicbritishspares.co...rsunk-screws-3-57-1040-a65-t120-tr6-t100



The three inner retaining plate screws therefore can loosen without the outer screws becoming loose which seems to be what has happened.

Last edited by L.A.B.; 09/21/20 1:09 pm.
Re: clutch slips
L.A.B. #824394 09/21/20 10:42 pm
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Another pre-OIF difference I didn't know about. And I've since seen that Splash's bike is a 1970 Tiger. I'm sure genuine manuals, or at least decent quality reprints, are easily obtainable. If the clutch centre is interchangeable with the later version it might be as well to get one - punched-over long screws seem a lot less likely to come undone.


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Re: clutch slips
Tigernuts #824396 09/21/20 11:36 pm
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Originally Posted by Tigernuts
If the clutch centre is interchangeable with the later version it might be as well to get one.

It is.

https://www.triumph-spares.co.uk/t120-t140-shock-absorber-unit-57-4435

http://www.britcycle.com/Products/57/57_4435.htm

Re: clutch slips
splash #824418 09/22/20 4:27 am
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Pictures below... Aright, I got into it further today. I hope the only reason was that the main shaft nut was too loose and it was. I used a impact drill but before i could hold the hub from spinning it easily came off. I was able to pull the clutch rod out from the primary side with a fast pull with hand. It was slightly mushroomed on that end but straight as an arrow, might as well get a new one though. It also had wear on the primary side if unless the slight step down is how it supped to be (?). Further down I pulled the drum off with 3 jaw puller without the jaws. Yes, the 3 screws were as loose as shown in the picture. Is the result of these 3 screws being loose caused by the main shaft nut being loose? No screws were stripped and I couldn't find were the metal flakes in the grease in the bottom of the primary came from so...

Another wonder is about the thrust washer, in the pitcher you can barely notice a slight bevel in the inner diameter (ID) of the washer where the flat head screwdriver is. Is that wear and tare or supposed to be like that. I believe I recall it being like that out the package. Which way does it go?

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Last edited by splash; 09/22/20 4:41 am.

1970 Triumph tiger owner
Re: clutch slips
splash #824473 09/22/20 4:53 pm
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Probably not glazed plates then!

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Re: clutch slips
splash #824488 09/22/20 7:57 pm
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Hi Splash, The rod is junk. The bushing on right end of main shaft is worn or you wouldn't have been able to pull rod through it. However the rod is very forgiving to worn bushing. The thrust pad in 3 ball cam will certainly have some damage as well. Again fairly forgiving. At this point I would just replace rod & not take trans cover off yet. The rod damage was not from loose screws, but from incorrect rod adjustment. Loose screws gives rod more play.

Back of basket looks good. It looks from what I can see should work fine after you fix the drum issues.

The small hub on main shaft photo is not sharp enough to evaluate it. From what I can see it will still give further service.

Thrust washer photo is not sharp to evaluate. Also need to see both sides & measure thickness. A worn thrust washer skews spring tension & can promote clutch drag. I would probably replace the washer. The bevel on washer depends on the washer at hand. Generally steel backed washer the steel side has chamfer, but obviously the bronze side goes towards basket. The all bronze washers often have a much larger chamfer. On these I always put chamfer towards basket. If you put chamfer to the small hub side, washer only centers on a small surface.

The original hubs work good. The repro hubs work ok, but the 4 small holes around flange can/will have very tiny burr which can chew the solid bronze washer very quickly. A 100 miles & you'll find bronze chips on bottom of primary case. Cure is to very carefully chamfer the edge of the 4 holes all around so washer doesn't get cut. The hub is not hardened so fine emery cloth wrapped on a pointed dowel or the like will work.

Regarding spider in photo, it has some wear for sure. How much taper is there from the base of arm compared to tip of arm? Overall wear of arm width is critical. I'd like to see sharp photo of the side of back plate that the spider rubs on. As you found front side of spider & front plate get basically zero wear. But bore of front plate & shoulder of spider takes wear so that must be accounted for.

Hard to say for sure, from photo, but it looks like top of screw holes are probably elongate/oval. That is a problem. More importantly DO NOT!! reuse the 3 screws. They have taken a beating & the head of screw & shank near head is at great risk of fracturing if reused. Trust me on this.

From the photos if you assembled with new screws, loctite on bone dry threads, tightened very tightly & the slots staked, the hub would work. Still the distortion of threads may still allow screws to work loose.

If you can at all afford it, I'd recommend new cush hub assembly. For sure I'd get the later version with hex bolts 54-4435.
If you look at photos of cush hub at Bonneville Shop very closely you'll see the early 3 screw version actually uses the same outer drum....
Also looking a photos of both new ones, notice how much the spider sticks out on back of rear plate. On yours it appears in photo, your spider sticks out much further, indicating wear in spider arms & back plate. This also effects end play of the basket as it give excess play on front side of basket. So you add that to thrust washer play for total play... Again effects spring tension & drag.

Do you have a clutch holder tool so you can properly torque the clutch nut with torque wrench? Trust me do not guess on this. Clutch nut is single use all steel locknut. Hardware store all steel works fine. I feel loctite 242 or 243 is a good plan for clutch nut. These nuts will work loose, especially if there is any play at all on the spline. Kind of sounds like your nut may have been loose. That is not cause of the 3 screws coming loose. However a loose nut will cause small hub to come loose on taper, break key & damage main shaft taper as well.

To be clear, this stuff is not all that simple until you understand it well. The clutch is not very forgiving. If everything is not right, it won't work right.

Before moving forward ordering parts, I'd like to see measurements of thrust washer & very clear detailed photos of the other parts mentioned.

The complete hub is $152 + shipping to HI. We need to get this right this time.

Very detailed photos of steel plates & friction plates after cleaning both with gasoline. Dry with rag, then lay in sun.

There is the 1.400" formula that can be followed to compensate for friction pad wear that I've found works really good. We'll get into later. As I recall you have a verner caliper to measure the parts with. That is a must. Hope ot hear from you soon.
Don


1973 Tiger 750
Re: clutch slips
splash #824516 09/23/20 12:09 am
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Re: clutch slips
splash #824522 09/23/20 1:09 am
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Perhaps its because I’m a long term owner of pre-unit (ie much older) parts that I’m less concerned about the signs of wear in your pics.
Admittedly my thoughts are only based on the pics, and measurements and first hand examination would be more convincing, as Don says.

Of course, a new clutch shock absorber hub would be best as advised. However, you may wish to try the following, if you’re as tight as me!

The rubbers look to be ok, so see how the 3 screws fit into the threads. If they wind in straight, without much slack, they may just do further service.

They, and the holes they go into, will require thorough solvent de-greasing, then thorough drying, before application of loctite, and serious tightening. See my earlier advice on this, using a vice and screwdriver bit (it works!).

Then dot punch next to the slot as Don mentioned posts ago.

That should sort out the shock hub.

The thrust washer shows unusual wear patterns, but that may be due to the unusual movements of the parts. Install a new washer, bronze/copper side to the basket, steel side to the hub flange.

I don’t know what is the best centre nut for your model, mine uses a nut with tab washer, but yours may take a locknut.
Either should work fine, when torqued properly. That is a crucial thing, to torque that nut properly. Don’t rely on shocking it tight with an air gun, it needs torquing.

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Re: clutch slips
splash #824556 09/23/20 2:24 pm
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To assemble the damper you need to put the mainshaft in a soft jaw vice, put the hub on the mainshaft, put the damper housing and spider on the hub, put in the large dampers, use a clutch holding tool to turn the damper housing to compress the dampers, put in the small dampers.
You need an impact driver to set the screws.
The A65 changed from the six countersunk screws to three through bolts to fix the screws backing out problem.

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Re: clutch slips
splash #824560 09/23/20 3:41 pm
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I wonder if it's possible to drill out and tap a 6 screw clutch hub for 3 bolts and if it would be an improvement.
I recently had one that the 6 little screws would not come out. I tried penetrating fluid, heat, impact driver, screwdriver with wrench attached - no go.
I finally drilled all 6 and I believe I weakened the threads some. I see the bolts are 1/4 x 28 x 1 1/4.

Also, seems you could extend the life of a worn back plate like this one by drilling new holes (and tapping for the bolts) in a new location.
This would shift the contact patch of the spider to an unworn area.
[Linked Image from i.imgur.com]

Last edited by Nick H; 09/23/20 3:51 pm.

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(2) 1967 Triumph "Choppa"s
1974 Indian ME125
1960 Harley Servi-Car
Re: clutch slips
splash #824580 09/23/20 7:07 pm
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Hi Nick, I looked into that. Not really a good place to move it to. Now you have oil directly interring vane space. I chucked up plate in lathe & was hoping to resurface using carbide bit. Not possible. Too hard. It needed to be ground. I don't have capability to grind it. The plate is hardened.

I see new screws are not so easy to come buy & costly but available. Plus you need screws of correct thread. I don't know what thread is. CEI? At work I've seen many times guys reusing screws/bolts that came loose that takes force. Very often the head or shank breaks off.

We'll see the condition of parts after splash posts them. At a point you have to bite the bullet & pay for new. Only close exam will tell if that point is reached. $30 for new screws is certainly not a waste of money if the it saves broken heads. Like I said Triumphs are not simple & demand perfect work. They are not forgiving at all. Proof is in the pudding. This is 2nd failure. The 3rd must be prevented even if means new hub.

Regarding lock nut, the later shaft/hubs have no provision for lock tab. The large thick washer covers the area. This washer is very specific part. Hardened & only rests on tip of splines. A lock tab could be fabricated, but it would take some doing. Hub properly installed with wiped dry tapers, new lock nut tightened to spec with blue loctite, I've never seen nut come loose. Again the splines should have zero play. Light press fit is best. However... I've observed many/most new parts are .0002 out of spec. Meaning the spline is an easy sliding fit. So it can/will work on the splines. Loctite is very advisable in my mind. Nut will come off no problem later. Washer can get glued in. Heat gun on washer frees the loctite & washer will pull out easy then.

Jury is out on parts needed until the true condition is known. Keeps us on the edge of our seats...

Don


1973 Tiger 750
Re: clutch slips
splash #824602 09/23/20 10:07 pm
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Yes the plates are very hard. I tried to drill small holes so I could peen over the screw with a carbide bit and it was very slow.
Of course the old holes could be sealed off.
I believe the screws/bolts are UNF and not hard to find and reasonable.
The 6 little 1BA screw are pricey - for a screw.

Last edited by Nick H; 09/23/20 10:13 pm.

1966 BSA Lightning
(2) 1967 Triumph "Choppa"s
1974 Indian ME125
1960 Harley Servi-Car
Re: clutch slips
TR7RVMan #824622 09/24/20 2:40 am
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splash Offline OP
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Originally Posted by TR7RVMan
We'll see the condition of parts after splash posts them.

I posted 6 new pics above. Did you miss them?

Koan, or someone, what is a way to hold the clutch basket when torquing down the main shaft nut?

Last edited by splash; 09/24/20 5:31 am.

1970 Triumph tiger owner
Re: clutch slips
splash #824627 09/24/20 5:28 am
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Cannot tell from the picture, what is the clearance between the outer cover and the spider, O.D. and I.D.? Too much and it lets the spider push on the front and back plates which will work the screws. You can use Loctite Liquid Metal or JB Weld on the O.D. of the plate to take up clearance. The only time you will be taking it apart is to change the dampers and the heat required to break the Liquid Metal will destroy them anyway.

Re: clutch slips
splash #824629 09/24/20 5:57 am
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splash Offline OP
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So, in the 3rd and forth picture the center is not flush with the front cover which I haven't removed. That center hub (spider) supposed to be flush with front cover, eh? I need to press it a little more toward the front cover, right? Next put the back cover plate on. The back plate is the one that keeps getting lose and I can't understand why. I wish had not changed the f'n dampers during the rebuild. Maybe I don't have them pressed all the way to the front plate where needed to be so the back plate can fit nice and snug? IDK, getting frustrated with the _hit.

Last edited by splash; 09/24/20 6:07 am.

1970 Triumph tiger owner
Re: clutch slips
splash #824633 09/24/20 7:04 am
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Hi splash, My apologies, yes I did miss the pictures. Very sorry.

The thrust washer is discolored, but not chewed up. If it's still flat and... the center bore still fits good on small hub, and if it's got grooved & not worn thin, it could be reused. Again I find the solid bronze washer works better with chamfer facing basket. I think I see a small "shoulder" worn in the chamfer?? I find I've seen that when chamfer is facing the small hub.

Actually the back plate doesn't look that worn. If I get time tomorrow,

Looking a photo of spider & rubbers. Those are correct rubbers, installed correctly. However in the photo it looks like spider has a "step" worn in the arms. Looking at arm at 1 o'clock position. You see the machined area where the spider rides in bore of rear cover. Then you can see shoulder at base of arm. The shoulder steps down to the arm. As I recall & from photos of my lightly worn spider, years/miles ago the step is actually worn into the spider arm & base circle. Here's a link to CBS & eBay new spider to compare:

https://www.classicbritishspares.co...t140?_pos=1&_sid=2772eda66&_ss=r


https://www.eBay.com/itm/GENUINE-TRIUMPH-3-SPRING-CLUTCH-SPIDER-57-4636-T100-T120-T140-BONNEVILLE/142274450808?hash=item212037d578:g:uWUAAMXQYwFRhKlF

You can see where they machine the OD of the spline, then pull tool bit outwards & face the spider or something like that.

If I get a chance I'll measure the end play of my old worn spider. The cush rubbers must be removed though.

If you have a proper holder in your vise made from a piece of flat steel & old clutch steel plate with long handle bolted to it, installing rubbers is safe & easy job, with no damage to you or hubs. I've installed lots of rubbers, if at all possible you'll need to make the tools. If you keep bike, you'll use them again. Rubbers don't last long these days.

The brown rusty looking deposits on spider arms are somewhat normal. These arms take a beating on the back plate.

I wonder if the loose screws allowed things to wobble & accelerate wear?

In the end of the day you'd be best off with new later version with hex bolt cush hub assembly.

I don't know what your end play is, but if you reused it, it would still work, just not as good as it should. The clutch should not slip. It will release, but probably not perfectly. Your budget. Our time is free so if you choose to take a chance on the old one, you don't have a lot to loose financially.


I see L.A.B. posted link to the 3 screws Classic British Spares. Good price. They say thread is 28tpi. I'd verify the thread before ordering.

At this point in my mind, you need rod, thrust washer, main shaft lock nut, primary gasket. New cush hub assembly, or... 3 screws.

Sleeping on it, thinking about the 3 screws I'd use red loctite 271, easy to buy. It holds very strong. Will release with heat gun. Heat until spit boils freely, they'll come out. Clean all threads & head areas bone dry. Freely apply 271 to threads & head. Tighten screws tight as you dare. Don't break head off, but really tight. Not a rattle gun. You need to feel the tightness.

Main shaft thread is 9/16-18. You can use clevelock type lock nut which looks like most of the Triumph lock nuts. Or the conical all steel lock nut. They are domed shaped with the top of dome pinched in to lock. Avoid nylock. they don't hold tight enough. I always use loctite 242 or 243 as well. Torque to 50#. Do not guess!! The same holder tool for installing clutch rubbers is used to hold cush hub during torqueing

Notice on new version cush hub the hex bolts are swaged over on their ends. Swaging looks rather like a screwdriver slot. If not swaged they can/will back out! Just like your screws. Triumph got smart with the long hex bolts. It is impractical to drill your hub & install hex bolts. You need to machine relief in drum for head clearance. As well as drill all the way through drum. Drilling hardened back plate not easy either.

Any thoughts?

Don


1973 Tiger 750
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