Lost Clutch.

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Is there a possibility that a thick outer plate has been used instead of the thinner later version. The thicker earlier plate went with the 4 thicker clutch discs. The later thinner plate went with the 5 thinner discs. 5 worn discs plus the thicker plate might add up to the stack height he has.
I haven't experienced this kind of fault yet because my 2 bikes are still original. Mixing non matching parts is usually a problem. Has the clutch ever worked correctly on the bike in question while Larry has had it? Has someone " played around " with it?
Dereck
 
OOnortonOo you can edit your post. After entering it, you can go back in and look at the top of the area you write in. Click on Edit and change what you wrote.
I do it quite often because my fingers seem to be too big for the keyboard.

sorry Larry, I missed your comment about the clutch pack height. That is your problem I am sure [ well maybe ]. The diaphragm is over extended, and not exerting the pressure it should. Diaphrams usually get weaker as they go "over centre".
Dereck
 
kerinorton said:
OOnortonOo you can edit your post. After entering it, you can go back in and look at the top of the area you write in. Click on Edit and change what you wrote.
I do it quite often because my fingers seem to be too big for the keyboard.

Following a recent calamity here where significant volumes of information were deleted from posts via the original poster "editing" his post, I believe Jerry Doe changed the edit function to allow the original poster to edit for 24 hr, but thereafter editing access is denied. If I have this wrong perhaps a moderator could step in and clarify the editing policy.
 
concours said:
The transmission mainshaft/pushrod/actuator is suspect here. That RH bearing, being retained by the nut/pivot assembly must be examined. Have you checked that the items 33-39 shown here are all present and aligned as they should be? http://www.oldbritts.com/1973_g9.html

Yes, thank you. I have checked those items and they all seem to work fine. Also I recently replace the center hub of the basket with a new hardened one. That's my dilemma, everything seems to be just as it should. I'll be checking more on the clutch height soonest to see if that will help. Though last time I checked it it appeared just right.
 
L.A.B. said:
lwmcd1 said:
The stack height of the plates with pressure plate measured 1.246.
It should have been to large to fix in the large circlip but with difficulty I got it in.

According to the dynodave data, normal stack height should be 1.167" (4 friction plate + "thick" pressure plate) or 1.172" (5 friction + "thin" pressure plate).

http://atlanticgreen.com/clutchpak.htm

I'll be for sure looking into that closer. Thank you.
 
I am thinking like Concours .... that the diaphragm may be popping over center, or right on center. If this is the case, you should feel the pull in the lever suddenly diminish, like what happens drawing a compound bow.

I take it that the loss of clutch happens only under actual riding load. If you can make it happen on the center stand, then the cause should easily be found.

Good luck.

Slick
 
texasSlick said:
I am thinking like Concours .... that the diaphragm may be popping over center, or right on center. If this is the case, you should feel the pull in the lever suddenly diminish, like what happens drawing a compound bow.

I take it that the loss of clutch happens only under actual riding load. If you can make it happen on the center stand, then the cause should easily be found.

Good luck.

Slick

Thanks for the reply. Doesn't seem to be the case . But i will be checking clutch stack,again, soonest.
 
texasSlick said:
I am thinking like Concours .... that the diaphragm may be popping over center, or right on center. If this is the case, you should feel the pull in the lever suddenly diminish, like what happens drawing a compound bow.

I take it that the loss of clutch happens only under actual riding load. If you can make it happen on the center stand, then the cause should easily be found.

Good luck.

Slick

+2 agreeing with Concours and slick....

that makes the most sense. Your clutch rod throws the diaphram out to a point where it's completely unloaded and balanced against going the wrong way by the diaphram retaining ring.... You push the bike, and at some point the diaphram pops back down...
 
WZ507 said:
kerinorton said:
OOnortonOo you can edit your post. After entering it, you can go back in and look at the top of the area you write in. Click on Edit and change what you wrote.
I do it quite often because my fingers seem to be too big for the keyboard.

Following a recent calamity here where significant volumes of information were deleted from posts via the original poster "editing" his post, I believe Jerry Doe changed the edit function to allow the original poster to edit for 24 hr, but thereafter editing access is denied. If I have this wrong perhaps a moderator could step in and clarify the editing policy.

Yes that is correct.

If anyone is desperate to edit a message after 24hrs then PM the edit details to me [L.A.B.] and I will do it.
 
I think your stack height is too high. The higher the stack, the closer the diaphragm gets to the center "pop-over" position at full lift.

With the engine off, I suppose your diaphragm is getting very close to center, then at rpm, centrifugal forces, coupled with engine vibrational dynamics, causes the diaphragm to pop over. This would produce the complete loss of clutch pull and clamp force. A slight bump pops it back.

LAB gave you DynoDave's stack heights. Get the height right and I think your problem will go away.

I think Old Brits offers a set of plain shim plates of various thickness to adjust the height. You pick the one you need and send the rest back. I would consider buying the whole lot, as you need to compensate for friction plate wear over time, and will need to swap out shim plates.

Let us know what you find. Good luck.

Slick
 
texasSlick said:
I think Old Brits offers a set of plain shim plates of various thickness to adjust the height. You pick the one you need and send the rest back. I would consider buying the whole lot, as you need to compensate for friction plate wear over time, and will need to swap out shim plates.

https://www.oldbritts.com/ob_clutch_info.html
Sorry, but we can no longer do shim plates due to the increased cost of precision grinding the plates. We may still have some shim plates in stock and when they are sold, they are gone. Check our clutch page Gearbox, Clutch for the plates we still have available. The shim plates that we do still have in stock are plates that we have precision ground on both sides to guarantee a true flat plate.
 
Thank you all so much,
I hope to have her sorted out soon. I'll keep you all updated.
I'm stubborn and don't give up easily.
 
lwmcd1 said:
concours said:
The transmission mainshaft/pushrod/actuator is suspect here. That RH bearing, being retained by the nut/pivot assembly must be examined. Have you checked that the items 33-39 shown here are all present and aligned as they should be? http://www.oldbritts.com/1973_g9.html

Yes, thank you. I have checked those items and they all seem to work fine. Also I recently replace the center hub of the basket with a new hardened one. That's my dilemma, everything seems to be just as it should. I'll be checking more on the clutch height soonest to see if that will help. Though last time I checked it it appeared just right.


a question. did the problem occur after you changed the hub?
Dereck
please let us know what you find. I think stack height is the problem though. Measure everything. Its ok to make mistakes. That's the way we learn to not make them again.
 
Nope, the center hub was replaced a while ago. Good thought though.
Will be checking on stack next.
 
sounds like you have had that problem for quite some time. I noted that you had to fit a thinner retaining circlip in the hub to hold the diaphragm. I don't think that is a good idea. Fix the problem and use the original double layered circlip [ not sure what its called ].
Dereck

When you refit the clutch hub, I suggest you get a hardened thick washer to go against the spline. Fit the lock tab on top of that then do it up. Remember , parrallel splines are not the best things for holding things together. There will always be play, and the shaft and hub will always rotate against each other. That's why those nuts always come loose [ and splines wear ], and hence you will always see wear on that washer. Never fit the soft lock tab against the spline for the now obvious reason.
[ and that's the reason why they use a taper to secure the drive sprocket to the crank shaft. ]
 
kerinorton said:
sounds like you have had that problem for quite some time. I noted that you had to fit a thinner retaining circlip in the hub to hold the diaphragm. I don't think that is a good idea. Fix the problem and use the original double layered circlip [ not sure what its called ].
Dereck

When you refit the clutch hub, I suggest you get a hardened thick washer to go against the spline. Fit the lock tab on top of that then do it up. Remember , parrallel splines are not the best things for holding things together. There will always be play, and the shaft and hub will always rotate against each other. That's why those nuts always come loose [ and splines wear ], and hence you will always see wear on that washer. Never fit the soft lock tab against the spline for the now obvious reason.
[ and that's the reason why they use a taper to secure the drive sprocket to the crank shaft. ]

No, actually I used the same outer circlip. I replaced the one behind the basket with a new one .
 
kerinorton said:
Is there a possibility that a thick outer plate has been used instead of the thinner later version. The thicker earlier plate went with the 4 thicker clutch discs. The later thinner plate went with the 5 thinner discs. 5 worn discs plus the thicker plate might add up to the stack height he has.
I haven't experienced this kind of fault yet because my 2 bikes are still original. Mixing non matching parts is usually a problem. Has the clutch ever worked correctly on the bike in question while Larry has had it? Has someone " played around " with it?
Dereck
The clutch worked fine for years before it started acting up.
 
Well guys I found the problem. I inner spline of the 063979 Clutch Center was worn smooth. So it was not turning with the sleeve gear when kicked over.Thanks loads for the help.
 
Interesting.
Was yours an alloy clutch center?
How were the outer splines where the clutch plates mesh?
How are the mainshaft splines looking?
 
lwmcd1 said:
Well guys I found the problem. I inner spline of the 063979 Clutch Center was worn smooth. So it was not turning with the sleeve gear when kicked over.Thanks loads for the help.

Good job, glad you solved it. :idea: :mrgreen: How did you use a new small circlip (previous post) and not notice horribly worn splines? :?:
 
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