Additional Clutch plate?

L.A.B> - thanks for the info about the RGM seal; the one I have looks the same as the one in the 2008 thread; I will try it and see; I will be very disappointed if it does not work.

It is always a dilemma as to where to source parts from; especially here in the colonies where postage/freight charges are such a factor; so I generally try to buy a few items that I need from whatever supplier I choose, and invariably some suppliers can provide some items but not others, and there are interesting price differentials between them. In this case I needed some other incidentals from RGM and as they had the seal I bought it from them. Hopefully it will not turn into a saga, but having read those threads I am not holding my breath. I will let the forum know how I get on.

L.A.B.'s most recent posts in this thread pointed out issues that forum members have had with the RGM clutch seal. His references to prior threads contained photos of the seal, which is inserted into a modified form of nut that secures the clutch centre hub. I had bought one of these, and installed it yesterday when I put in my new clutch plates. It works fine for me; at least so far as I can tell from wheeling the bike around the garage and engaging and disengaging the clutch: I haven't ridden the bike yet.

I can see how there might be issues with this nut/seal in some cases. It is about twice the length of original nut (or is that twice the depth?), so that if your clutch is set up so that it needs the clutch adjustment screw to be screwed quite far through the diaphragm spring, the clutch adjustment screw could hit the end of the RGM seal before it fully pushed the clutch rod through the clutch and gearbox to allow the clutch to be disengaged. I wonder whether the issues that some members have had with this seal could have been influenced by the adjustment of the clutch cable, which in turn influences the position of the clutch actuator, and therefore presumably influences the position of the clutch rod from the gearbox end; if the clutch rod is not pushed enough towards the clutch spring from the gearbox end, it will not protrude enough towards the diaphragm spring to allow the adjustment screw in the diaphragm spring to be out sufficiently that it does not foul the rgm seal nut.

When I saw how little movement there was in the clutch rod between being fully engaged and fully disengaged I decided against trying to include an xtra clutch plate. I decided( probably illogically) that given the limited potentially limited range of adjustment when using the RGM seal I might not be able to engage the clutch sufficiently to separate all of the clutch plates. I spend a bit of time measuring the various plates; I had bought a new Barnett set of friction plates and steel plates. The Barnett plates were slightly thinner than the stock plates, so I reinserted the stock plates to give a slightly higher stack height. I don’t know if that has made any appreciable difference to the effort required to pull the clutch; it is certainly not one finger effort, but it seems ok.

Only clutch rod seal I know of is made by Dave Comeau but is sold world wide. I used a thinner washer under it on Peel and Trixie which both had/have sweet clutch action years at a time.

Chris T said:

I wonder whether the issues that some members have had with this seal could have been influenced by the adjustment of the clutch cable, which in turn influences the position of the clutch actuator, and therefore presumably influences the position of the clutch rod from the gearbox end; if the clutch rod is not pushed enough towards the clutch spring from the gearbox end, it will not protrude enough towards the diaphragm spring to allow the adjustment screw in the diaphragm spring to be out sufficiently that it does not foul the rgm seal nut.

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Yes I see what you mean, I think that's the first RGM nut we've heard of that's worked, but clutch pushrod clearance would usually be set with the cable fully slackened off, so the pushrod will be at the "fully retracted" position, and with zero lift at the actuator.

To project the pushrod further out through the RGM nut as you describe would probably involve over-adjustment of the cable, causing the actuator to be set partially lifted when the pushrod clearance is set, and that may result in a loss of clutch lift.

Duh the amount the rod sticks out is a built in fixed amount of distance from the actuator crook to the DS rod end and basket position or stack height has any bearing on how much sticks out to seal, unless too many shims behind basket locator clip. No one can adjust the cable until clutch primary fully assembled then should only need adjuster scerwed in to touch rod then backed off ~1/4 turn. Best chain alignment should have basket just barely cleaning inside of case.

I've always been 1/4 turn or less kind of guy. Otherwise, I can't get the rod to push out enough, I had to take off all my washers and I think I even ground down the something to get Dave's seal to work for me. Maybe it was the seal body, it may be in the instructions. I can't believe anyone could get that RGM one to work if it actually looks like that, unless the rod, actuator lever or cable is changed somehow. And that would mess up where you are on the diaphragm pressure curve.

I've tried extra plates and it would require something in the order of .005 more stack height to make mine work without slipping.

I've often wondered if the pressure curve on diaphragms aren't different among them.

Dave
69S

Hobot,

just to be clear, are you saying that clutch cable adjustment cannot adjust the position of the clutch rod in the gearbox and clutch?

If so, then I can only think of a couple of reasons why my RGM seal worked and the others did not. First, maybe RGM has made it fractionally shorter (I wish that I could have found my micrometer and measured it). Second, as you have suggested, any shimming of the clutch hub - and perhaps even the thickness of gaskets between the primary and the gearbox might have an effect of increasing the total width of gearbox and primary so that the rod is too short to protrude out of the seal. Also, mine is a 750; is the clutch hub shallower for 750s than 850 ? That would not be surprising given the extra plates that the 850 clutch has. I assume that the same clutch rod is used for all models. If so, and if the RGM seal was designed on a 750, it may not allow sufficient of the an 850 rod to protrude from the end of the seal to make it work.

Chris T said:

Also, mine is a 750; is the clutch hub shallower for 750s than 850 ?

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No, same part. later 750 and 850 hub/centre was hardened so it has a different part number.

Chris T said:

That would not be surprising given the extra plates that the 850 clutch has.

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But the 5 plate clutch has thinner friction plates and pressure plate. The 5 bronze plate clutch was also fitted to late 750 models.

According to the DynoDave info. the 850 stack is taller, but only by 0.005"
http://atlanticgreen.com/clutchpak.htm

I listed what can push basket out too far but apparently the real issue is which clutch nut seal version you have. Here's some more scuttlebutt to clarify the various details.

http://www.nortonownersclub.org/noc-cha ... 21388/view