MC-5 clutch adjustment

[skiracer]

I need some help in adjusting the clutch on my 76 MC-5 250.  The nuts on the clutch hub are adjusted about three threads showing on the studs, and the clutch does not work.  Do I need to tighten the nuts, or back them out in order to give me additional movement of the clutch plates. Thanks, James

 

[penton117]

Hi,

You didn't mention what the symptoms were but backing the nuts out will give you less spring tension and increased movement of the actuating rod. This is in turn will allow the plates to separate further, also slightly easier pull at the lever.

 

[skiracer]

Thanks for the reply.  The problem I am having, is when I pull the clutch lever, the clutch is not grabbing.  I adjusted the cable out on the bottom which gave me a little clutch action, but not enough to hold the bike standing still.  I thought if I adjusted the plate tensions, I would increase the amount of grab.

 

[penton117]

Ok, I understand.  Think of a clutch as a switch that connects the engine to transmission. In simple terms, half the plates are connected to the engine, the other half to the transmission. When you let out the lever the springs push all the plates together, connecting the engine and transmission. When you pull in the lever, the plates are forced apart, disconnecting the engine and transmission. If pulling in the lever does not fully disconnect the two, start by backing out the nuts on the clutch basket. This will give the plates more "room" to separate from each other. If this is still not enough, you probably have one or more plates which are warped, causing the drag that you are experiencing. Good luck.

 

[john durrill]

James,
check the runout on your clutch,
 you can use a dial gauge or a pointer fixed to the engine case.
 if all the plates are the right thickness and not warped. if all your springs are the same length. then check and see if you can adjust the nuts to give you as little runout as possible. its sort of like trueing a rim.
you might want to pull the clutch lever in an inch or so and fix it with a rubber band
to load the clutch assembly. that would give you a more accurate reading. Thats a trick Bobby Lucas passed on to me and he said at one time there was a post on here about how to do it. He likes no more than .006 runout.
 set up like that the clutch last almost forever.
Hope this helps,
John

 

[skiracer]

Wow!!! I never expected to get such great responses. Thanks so much for your time and effort.  However, after playing with the plate screws, I still do not have a working clutch.  I guess I have a few bad plates.  So my next question, where can buy the special hexagon screwdriver #51.12.007.000, due to one of my spring bolts has a broken slot for the screwdriver?

 

[john durrill]

James are the threads buggere`d up?
if not you can use an equaling file to deepen and square up the screw driver slot and a socket turned with your fingers to get the nut off. If that dosent work you can get an allen wrench , have some one weld it to a small rod and go through the opposite side of the motor to hold the screw with as you turn the nut.  I Havent been able to find any suppliers for an allen wrench that long
John & Peter



Edited by - John Durrill on 08/01/2002  7:40:13 PM

[skiracer]

John, do you know what size allen wrench is for the spring nuts?  Thanks, James

 

[john durrill]

James ,
 sorry to take so long , but i had to find one to make sure. its a 4 mm i believe
John

 

[skiracer]

John,
Thanks.  I tried to get to the back of the bolts but couldn't.  I ended up removing all of the good one's and hack sawing the final one.  I got it all back together and found another problem.  I don't think the disengaging lever is moving the pushrod far enough.  So either the diengaging shaft or the pressure bolt is worn out, (New style bearing cover.)  Thanks again for the help. James

 

[john durrill]

James,
 you should have two rods and a ball bearing between the actuator and the pressure plate.
 look and see if someone left out the ball bearing. the order should be one rod, rounded end facing the preasure plate, one ball bearing and one rod square end facing the ball bearing and rounded end facing the actuator
 That would give you the problem of not enough throw.
Might not be it but it does happen.
John



Edited by - john durrill on 08/07/2002  3:33:21 PM

[skiracer]

John,
On the updated covers, they use a solid shaft, and a concave race for a small bearing on the end of it.  I have re-installed my original old style cover with the three piece shaft.  I put three small washers on the center bolt of the pressure plate to extend the shaft length.  I tried the bike today, and I have a little clutch.  I am beginning to remember why I switched to a Honda back in 1978.  I guess I will have to keep trying.  Thanks, James

 

[john durrill]

James ,
 sounds like you just need the length of the stock rods . if the ones you have are short that's the problem. can you come up with a new bolt for the pressure plate? sounds like it may have been worn down or modified in the past.
 I can find no measurement in the book for the length on either. Never had one that did what you  describe with its clutch. ask Larry or Al to measure a new rod for you to get the length and the bolt on the pressure
plate.
 It has to be the sum of these parts = not enough length. One thing though. you do have stock levers right?
 not the short power levers. I have seen short levers not give enough throw on Sachs engines. and that gave the same result you are experiencing.
all this is if you have the right number of plates and the right thickness. not something that some pervious owner has added parts to that are not correct for the clutch basket and preasure plate you have.
 John



Edited by - john durrill on 08/08/2002  07:46:41 AM