oiling Triumph bonded clutch plates question ???

To soak, or not to soak ... that is my question. Bike is a 1971 Triumph TR6 that I'm putting back together for my Brother-in-law. I'm no expert, just a guy who likes to tinker and do my own work. It didn't run, so I stripped and rebuilt it, cleaning the clutch plates with an SOS pad and water. I've rebuilt 650 Triumph motors before, but don't remember if I soaked the bonded clutch plates in oil or not. Workshop manual I have don't say.

Just watched my Hughie Hancox Triumph unit 650 rebuild video, and he says nothing about soaking the bonded plates in transmission fluid prior to install, or even oiling them at all. Also watched my Triumph 650 rebuild video by Wes White ... and he says to soak the bonded plates in ATF before installation. So ... what say ye ??? Should I soak them in ATF overnight, or just install them dry ???

nortriubuell said:

Just watched my Hughie Hancox Triumph unit 650 rebuild video, and he says nothing about soaking the bonded plates in transmission fluid prior to install, or even oiling them at all. Also watched my Triumph 650 rebuild video by Wes White ... and he says to soak the bonded plates in ATF before installation. So ... what say ye ??? Should I soak them in ATF overnight, or just install them dry ???

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The 70-on 650 (and 750) models breathe through the primary, and therefore use the same oil in both compartments, so personally, I'm not sure I would consider using ATF in that situation. I don't see that it really matters one way or the other if the friction surfaces of the clutch plates are initially oiled or not.

L.A.B. said:

nortriubuell said:

Just watched my Hughie Hancox Triumph unit 650 rebuild video, and he says nothing about soaking the bonded plates in transmission fluid prior to install, or even oiling them at all. Also watched my Triumph 650 rebuild video by Wes White ... and he says to soak the bonded plates in ATF before installation. So ... what say ye ??? Should I soak them in ATF overnight, or just install them dry ???

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The 70-on 650 (and 750) models breathe through the primary, and therefore use the same oil in both compartments, so personally, I'm not sure I would consider using ATF in that situation. I don't see that it really matters one way or the other if the friction surfaces of the clutch plates are initially oiled or not.

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Good point Les ! The Wes White Triumph 650 rebuild video, is a rebuild of a pre 1970 650 motor. (and thus NOT breathing thru the primary) Where as the Hughie Hancox video, is of a 1970 650 motor, breathing thru the primary ... as you noted. Glad you pointed that out, as "if" I do soak the bonded plates, better to soak in the engine oil that will be used, and not ATF. (what Wes White used in his video.) As always, your input and comments are most helpful. Thanks

You're better not to soak the plates. A Triumph clutch should be dry regardless whether it is a pre 70 (separate oil) or post 70 (shared oil with the motor).
The oil which is very little, about 1 "- 2" deep (look at the level of the 3 small holes below the crank, this is the primary oil level) is there to lubricate the primary chain and to provide a little cooling to the alternator.

If you soak the plates you will get clutch slip. Whilst you have the clutch apart it's also a good idea to rough up the stator plates a little with a file (or I've heard of some people using the pavement).

Once you reassemble the clutch, start with the pressure plate spring bolts (or whatever they're called) flush with the bottom of the slots in the nuts, kick the bike over and ensure that the pressure plate is true (a wire pointer attached to a primary bolt hole can help here).

Once the clutch is running true, and you have the cable adjuster backed fully off turn the center adjusting nut till it just touches the clutch push rod and then back it off half a turn.

Finally, use the cable adjuster to take up the slack at the lever.

If you experience any clutch slip, turn the pressure plate nuts in half a tun at a time and then try again.

I hope this helps

All the best

Webby
(71 Bonnie, built from a pile of parts)

Typical classic Britbike clutches are DRY clutches. Do not oil any of the plates at all. You want them dry, and the plain plates de-glazed per the book.

Of course, "dry" plates in a "wet" primary case will soon become wet plates once the engine has been started.

L.A.B. said:

Of course, "dry" plates in a "wet" primary case will soon become wet plates once the engine has been started.

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More like moist :mrgreen:

Wow, thanks for all the replies They are going in dry NOW, for sure. So similar to a Norton clutch, makes total sense to NOT soak them in any kind of oil ... as they will then slip. However, I started "second-guessing" myself when I watched the "Triumph 650 rebuild video by Wes White". He does a pre-70 650 in the video. Just wondering now ... why in his video he recommends to soak the bonded plates :shock: Now that I think of it, I followed his advice when I put a Sparx rotor and stator in my 1979 Triumph T140E, and then soaked the bonded plates as per the video. And after a couple months, now THAT clutch slips So I need to take the clutch all apart, cleanup the plates, and put it back together. Hope I didn't ruin them ...

L.A.B. said:

Of course, "dry" plates in a "wet" primary case will soon become wet plates once the engine has been started.

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Centrifugal force keeps them almost completely dry unless you overfill, and in the case of Nortons, tranny oil migrates in via the pushrod tunnel (not nearly as prevalent with Triumphs).

The problem is, MOST people seem to overfill the primary for some reason.

Blowby through venting can push excess oil into primary too [ `70 on Triumph twins].