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slowkitty

Inability to disengage clutch after twin-disc conversion

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Dear all,

 

I have a Scura. Yes, the one that is prone to a grenading clutch. 

 

So I decided to convert to  a twin-clutch. Got a used set from Gutsibits. 

 

I installed the clutch. It came with new springs (the 5-ring ones) that are stronger.  I also have new SD friction plates and intermittent plate.

 

After reinstallation, the clutch does not disengage. There is tension in the clutch lever, which means that the pressure plate is being actuated. So, what happened after was:

1. I changed to the original softer (6-ring) springs.  Softer pull on the clutch lever, no disengagement still.

 

2. I read that the SD friction plates are thicker, so I machined skimmed it down to under the 8mm thickness of the stock plates. No disengagement. 

 

3. Checked that the intermittent plate is flat and not warped.

 

4. I have bled and changed the fluid out in the clutch master cylinder too.

 

The clutch still does not disengage. I am at my wits end. 

 

Contemplating doing a Non Destructive Testing on my aluminium flywheel and then reinstalling the original single plater.  Or look or CNC a steel flywheel.

 

Views, gents?

 

Andy

 

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Hi, docc,

 

Thanks for the input (no pun intended).  There is no disengagement on mine, period.  Nonetheless, it is something to think about. Will see what else comes in before I tear down the clutch (again!).  

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Scud also had some struggles with this.  I recall he traced it to the stiffer replacement springs. Sounds like you addressed  that already.

 

The drive hub is easy to overlook. It is not part of the clutch assembly.

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So, wait . . . when you converted to the twin plate clutch, which input hub did you use?

 

The single plate input hub differs.

 

You'll need a "twin plate" input hub for the full conversion.

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Dear docc,

 

I used the correct hub, i think.  

I will post some pics. How the heck do i post pics without paying photobucket?

 

cheers

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as Docc said you need to use the twin plate hub.... AND the actuating (?) rod. I think this part might be a different length.

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as Docc said you need to use the twin plate hub.... AND the actuating (?) rod. I think this part might be a different length.

 

Yes, I used the hub for a twin.  I definitely did not use the single plater hub which is shallower.  

 

Capture.JPG

 

Twin with hub installed.

 

Capture.JPG

The single plater and the twin comparison

 

The pushrod is the same as the single plater I think.  This was covered in another post.  In any case, I have tension when I pull the clutch lever, indicating the pushrod is pushing on the clutch pressure plate that in turn is pushing on the pressure plate.

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When I changed my single to dual, I did not replace the push rod. So a single plate rod works on a twin plate config.

 

Which flywheel did you install?

I have had troubles with the clutch leaver handle feeling sort of normal (but stiffer than in my memory), but not disengaging.

Eventually I took out the gearbox again, removed the starter ring gear (thus removing tension from the setup) and then had someone use his fingers through the hole in the clutch plates to check the springs, while I held the setup in slight compression.

We found out that at least two of the springs, maybe more, had not settled in the recess on both sides (flywheel/pressure plate). This caused the space for disengagement to be absent.

 

So in short: ensure you 100% correctly have all the springs in the recesses. Otherwise you can still install the assembly including starter ring gear, but it will not disengage.

 

 

EDIT: I also don't see the receiver cup (GU04082800) for the pushrod in your assembly overview on the floor... Did you install it?

 

 

04082800.jpg

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Dear Tinus 

 

Thank you for chipping in. 

 

Yes, the receiver cup is installed; it was omitted from the pic, as were the hubs.  I reckon that without the receiver cup, the clutch lever will not even have any tension since the pushrod will not be pushing against it (and the pressure plate/springs)?

 

The unseated spring theory sounds plausible. Something I have to bear in mind but I am really trying to exhaust all options before re-opening the transmission again.  I glued all of the springs to the flywheel and then attached the pressure plate.  Arguably it could be a dislodgement there.

 

andy

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 I glued all of the springs to the flywheel and then attached the pressure plate.  Arguably it could be a dislodgement there.

 

I used some copper grease to stick them in place in the flywheel, which I think was successful. I expect the dislodgement would have been on the pressure plate side as well. But as it were not my fingers on the inside replacing the springs, I am not sure;)

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FWIW, I use channel locks and lightly squeeze the last coil of the spring so it is secure on the boss when assembling the clutch. I'm guessing s wayward spring is your problem..

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I ended up alternating the original and the new (stiffer) springs - 5 of each.  I believe that the problem with mine might also have been a spring not seated correctly.  If you do take the motor out again, try laying it flat so the springs stand upright. When you put the pressure plate on, reach in with your finger to ensure that every spring is fully seated. Another way to tell is that the pressure plate will sit exactly level with the flywheel if all springs are in correctly. If even one spring is not seated, the pressure plate will be a little bit tilted.

 

The pushrod is the same for both clutch types. 

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Thanks for all the views. I just learnt that the donor bike for the clutch was a 99 V11 (in green). 

 

I guess I have to tear down and reseat the springs.  

 

Is there any sense in alternating the springs? To get that intermediate feel of hard/softness in the clutch pull?

 

andy

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When I rebuilt my twin plate clutch at 100,000 miles+, the OEM springs worked for me. And were cheap. "Glued" them in with blue LocTite on assembly.

IMG_2583.JPG.jpeg

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