M100B - Shifting Lever Roller Not Dropping Into Play

[Brad]

I'm having trouble with the mech staying in play and I'm hoping someone can help me with what I'm missing. Transferring into play, the shifting lever roller drops into the play notch but not all the way down. So, this causes it to return to scan. However, if I push the shifting lever down further as the roller drops into the play notch, the mech stays in play. It's not an electrical clamp arm switch issue because this happens during manual operation with the power off. The clutch has been thoroughly cleaned and moves extremely freely when off the mech. All clutch adjustments have been made according to the service manual - several times over. The safety plunger is adjusted and working as it should.

With the clutch back in the mech, it moves very freely except in the final stages of transferring into play. The roller drops 80% of the way down into the play notch, then for the other 20% it acts like the clutch is gummed up, which it's not. I can manually move the transfer arm down the last 20% to place the roller fully into the notch, but it doesn't move freely, up or down - kind of like there's something else connected in the process. So I thought maybe the clutch shifting lever wasn't moving freely at needed to be lubed at its apex. It is moving freely.

I'm hoping someone can help me with what I'm thinking is probably an overlooked "DOH!" adjustment.


Brad

[Brad]

Anyone? Anyone? Bueller?

Brad

[jukenorman]

I don't think there's any obvious answer that you haven't previously covered. There is a note at the end of clutch adjustment 4 that may be pertinent to your problem - although I expect that you've read it! I have previously come across a problem like this and it was caused by someone packing the thrust plate at the base of clutch with bearing grease which worked its way up the shaft making it gummy.

Norman.

[Brad]

Thanks Norman. Yes, I've redone all the clutch adjustments so many times that I finally realized it has to be something else. So last night I decided to compare the action on my R when it goes into Play. What I found is that the shifting lever roller in the R drops the same as the B. They both don't drop all the way down into the Play notch. So, I'm thinking the reason it doesn't stay in Play lies elsewhere. Something is making the clutch act like it's sluggish or binding up, and it only happens when the mech is moving into Play. The clutch and shifting lever action moves freely when moving into Scan. 

And it's interesting that you mention the thrust plate. After comparing the R action to the B, I started thinking about what might have been changed when I cleaned and lubed the clutch. This made me think the top thrust bearing might have something to do with it. I loosened the top adjusting screw and it started to stay in Play, but only sometimes. Do you think adjusting the thrust bearing might be the answer? Also, I haven't been able to find anywhere in the installation and maintenance manual that focuses on this adjustment. Am I missing it?

Another thought - Would adjusting the thrust bearing change all the clutch adjustments? In other words, after adjusting the clutch, would I need to go through all the clutch adjustments again?  
Brad

[jukenorman]

Hi Brad,
I'm afraid that I can't really help, I've rarely if ever had cause to carry out clutch adjustments even when I have replaced one. I would say though, if you loosened the top thrust plate and it then goes into play sometimes, that would maybe show that it was overly tight. But that adjustment you made to the thrust can be no more than a couple of thousandths of an inch? Is it the same in both directions? My gut instinct at the point you are at now, would be more oil!

The only other thing I might be inclined to try would be to be less severe on clutch adjustment 3 to see if that might help - if only because the note at clutch adjustment 4 infers that and "until all rotational motion is just taken out of sprocket" is a bit wooly anyway. I also note that clutch adjustment 3 then calls for adjustment 4. But that's really just clutching at straws, if you can pardon the pun!


Norman.

[Brad]

Thanks again Norman. I didn't want to do it, but I think I'm going to put the clutch from my R into the B and see what happens. This is about the only other thing I can think of trying in order to rule in or out if it's the clutch. I'll post the results once I'm done.

Brad

[Brad]

Well, I should have taken the extra time to punch out the yoke pin on the clutch when I cleaned it. Turns out that was the problem all along. Although it looked like the clutch was working freely throughout Play, Transfer and Scan, the last little bit of dropping the member into Play was just slightly sluggish. My bad for not going the extra mile with cleaning it.

Thanks for your input Norman. Now onto the next issue.

Brad