C: Clutch Twin clutch . centralizing plunger.

Cyborg

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C13/1 came on some Lightnings as did C1/1 the lightened clutch drum. View attachment 39033

I have a lightened drum like that. Seems to me that they were used on B’s (with the normal plate), but they stopped drilling holes in them at some point.
I wondered if my C13 was actually a C13/1 because it came in a bin that included couple of real Lightning parts. I see the hole pattern is different, wonder if they were all drilled the same or depended on the mood of the worker? Either way, I think mine is prettier than yours. Whoever did it, certainly gave it some thought.

D860FB22-68D6-432E-961E-05C258809784.jpeg
 

Bill Thomas

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Before I got the plungers to touch, It always drove me mad to feel drag when I could see lots of
play on the centre plate, Not always just sometimes,
Another funny one, We was doing a twin of someone else,
And found the spring for the Kickstart and over run was much stronger than the other shoe,
The wrong way round from what we were told, Without getting too involved, I unadjusted it ,
But still too strong, So thought we would just try it , And it was fine.
 

Gary Gittleson

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I thought this thread would be appropriate to discuss a related problem. On my D twin, I find that the C1 clutch drum notches have been worn (notched) from contact with the tabs of the primary friction plate. The friction plate is of the newer type, with bonded, non-segmented linings. The tabs on the plate are worn a bit too. I removed the resulting burrs from the tabs. But what to do with the drum? Should I carefully grind or file the notches or just replace the drum? The bike has some 50,000 miles on it and I'm pretty sure the drum is original. And what of the Lightning type drum? If I went with that one, I assume I'd have to change the friction plate as well.

Overall, the clutch behaves very well, after the attention I paid to bushes, plungers etc. The only annoying symptom is that If I come to a stop and then move on a short distance without fully engaging the clutch and then come to a second stop, the clutch drags enough to make neutral finding impossible. If I fully engage before freeing the clutch and then stopping, there's no problem. I'm assuming the primary plate is getting stuck in the wear notches.
 

Gary Gittleson

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Hi Norman,

Yes, I do have the needle roller setup. I replaced all the springs a couple of years ago and with that and your mod, the plate lifts off very evenly and overall, the clutch works very well, with the exception of the symptom I described. Under "normal" use there's no problem finding neutral. It's only a problem if I come to a stop after moving under partial engagement of the clutch.

So are you suggesting that the wear I see in the drum notches should not cause problems? I'm inclined to square them up with the side of a mini abrasive disk in a Dremel.

By the way, the C3 clutch carrier will not allow your valve-grinder mod for an O-ring at the back. It's the newer, thinner type. On the other hand, there's room for two O-rings at the outer end. I have been getting a bit of oil coming through so I'm going to try that, along with non-hardening sealer on the splines.
 

Peter Holmes

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The problem is you might get rid of the consequences of wear, but you will not get rid of the wear, the friction plate will now have a larger gap for the ears to slam back and forth in use and the problem will come back pretty soon, if you could get a friction plate with oversize ears that you could adjust back to a good fit without any backlash after you have Dremeled away the step, that would work, but failing that, and for a long term solution you need a new clutch drum.
 
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greg brillus

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Perhaps you could add a small weld to each tang on the clutch plate, without too much heat......(a cold dampened rag perhaps) then re work these to a proper shape, then clean up the matching slots on the drum..........So you either re work these parts, or buy new ones. If the shoes are hanging up this will cause drag in the clutch.......Perhaps the plunger springs are broken or weak......The bush in the C 13 could be grabbing on the C 20 nut, or not enough end float (C 19 shims) Even the shoe pivots C 5/1 can cause issues if the shoe pivots have been bushed oversize. It is important that the moving parts of the clutch do so quite freely without anything being tight or snug. Good luck with it.
 

timetraveller

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Hi Gary, I was just checking that one thing that can cause problems had been eliminated. It seems to me that you have nothing to loose by doing as you suggest and just tidying the slots and ears up with a Dremel. It might clatter afterwards but at least you will know that any problems are not being caused by 'hanging up' with the primary plate. Interesting that you have a 'thin'' C3. I must have been lucky as I have not come across one yet. Good luck with it.
 

stu spalding

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Perhaps you could add a small weld to each tang on the clutch plate, without too much heat.
Hi Gary, Greg's idea works fine, I used it on a Triumph plate, but like he says it must be kept cool. I dunked the plate in cold water after each weld, it doesn't take much heat to unstick the friction material. Cheers, Stu.
 
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