Very basic clutch replace question. RSVP

So, I'm going to rebuild my clutch on my 74 mk 2. It has had the same plates for quite some time according to the PO. It grabs and does not operate smoothly.

The parts needed are listed on Old Britts:

*Five friction plates Barnett ($64 set of five)
*Four plain plates, Barnett ($7.53 ea.)
*One pressure plate, ($124.41)


5 Barnett friction plates and four plain Barnett plates.

I have not opened up the drive side of the engine yet but if you were to replace your clutch would you include buying a new pressure plate or not?

Also, any other parts needed besides the two sets of plates?

I read somewhere on the Old Britts that they will send you some "Shims" and return the ones you don't use. Not sure what to ask for???
I understand how you need to bring the stack up to the circlip ring.

(*I already have the Old Britts clutch tool.)

Thanks in advance.

I just recently replaced my clutches and just sanded the plates clean and smooth then wiped them down with ATF and reassembled.

You will need a new cir-clip retainer, best to replace the part that holds everything together!!

Really easy to replace the clutches once you get in the primary, make sure to undo the drain plug first. I did not and had gear oil everywhere on the ground in my garage!!

Also get you a new primary seal, cheap and easy to replace!!

Might not be the plates, notched clutch center can have the same symptom. Best to disassemble and inspect before purchasing parts.

agree on taking it all apart first before ordering parts...had similar problems on my bike and it turned out the clutch nut was loose due to the lock plate flattening (common from what I've read here) and the plates were oily....fixed those things and the clutch works fine now, no new parts were required

As mentioned before, take the clutch apart before you buy any parts. Grabbing is either due to oil on the plates or a bad spring. I don't think that I have ever had a plain plate or pressure plate go bad. A notched center ate the teeth off several sets of friction plates, but they always worked fine until they started to slip. Clean the friction plates. Check to see that the diaphram spring is lifting evenly. If in doubt remove it and see that the fingers are all even.

Greg

I have found that Barnett friction plates are "grabbier" than either the stock bronze plates or the Sureflex (fiber on aluminum plate). I have known people to substitute one or more bronze plate in a Barnett pack.

Yes to inspecting the clutch center for notching from stock plates eating into it. The plates will not free up and shifting will be poor.If so, order in the hardened type ,it should "ring" when tapped with a wrench.Good luck.

Another vote for take it apart first.
If the splines on the center hub are not smooth - they look they have notches along each spline - careful filing will cure the problem. Notching on the center can make the plates hang up and make for poor clutch performance. If the notching is bad, go for the better, late hub (harder).
If you can still see the eccentric groove on the bronze plates - no reason to change, unless the plates are warped or the teeth that engage the center hub are hammered. I've spoken to owners who have put over 100K on those bronze plates.
Plain plates should last the life of the bike. On the Atlas, the tabs would wear down, especially if the cush rubbers were shot, but the Commando design puts very little stress on them.
Only replace the pressure plate if it doesn't release evenly.

Grabby clutches that don't want to release cleanly are often the result of either gear oil in the plates - leaking through the clutch actuator hole in the main shaft - or too much oil in the primary from a leaking crank seal or primary mounting bolt (two different causes, but same result in the primary)

Wow!

The advice here is just amazing. Spot on what I was looking for. Ok, so if the "Clutch Centre" (part # 063979) has minimal notching on the spline a very careful filing might do. Otherwise buy the :
"12-063979/A Alloy Clutch Center, 750 and 850 Commando 0 SO 175.00"
from old Britts AND check for fluid contamination on the plates from " leaking through the clutch actuator hole in the main shaft - or too much oil in the primary from a leaking crank seal or primary mounting bolt." Now I have a much higher confidence level of what to look for. Also, What would be the best cleaning solution for the friction plates?

Thanks again for the wealth of knowledge on this task ahead.

Hi Sky,

You should be able to clear the clutch with a single kick with the clutch lever pulled in. If the kick lever does not depress freely on the first kick, either the plates are sticking, or the splines are notched; in either case, after inspecting the splines, I would strongly recommend replacing the friction plates. Our bikes are old, with unknown history, and it often happens that cleaning old plates simply doesn't do the job; the replacement plates are cheap, in any case. While you're in the primary, consider replacing the clutch rod seal with Dave Comeau's seal; again, it's an inexpensive part. The remarks on tweaking the pressure plate thicknesses are directed toward tuning the clutch lever pull pressure. Wait until you're got a freely disengaging clutch, then worry about the stack depth. Fred Eaton recommends Barnett friction plates, and I've never gone wrong taking his advice. And don't overfill the primary.

Rick

So, the dang thing is "notched."

Hummm, looks like some $$$ to spend.

Dangitall !!!

Skyguyz said:

"12-063979/A Alloy Clutch Center, 750 and 850 Commando 0 SO 175.00"
from old Britts

Click to expand...

The alloy center will probably wear faster than a hardened steel stock one.

063979 CENTRE - CLUTCH - HARDENED TYPE C - - - 68.10 pounds from Norvil. Figure on $140 or so by the time you have it in hand. I have not always been able to can get the bearing off the center without damage, so you might check that before ordering. I think there is a wimpy clip back there too...


Greg

Mine was notched like your. I filed it. It works now. I have put about 5000 miles on the bike since filing it. I know it won't last as long as a new one. I think it might last a long time. I was surprised that a new one is only 140.00. I don't think an alloy one would last very well.

I have put many miles on Triumphs and have filed the clutch centers on those. I have never found replacement was necessary. Nigel