Failing clutch master or slave? Or just sticky clutch plates?

Started by Shadowbennie, June 29, 2020, 08:39:36 AM

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Screamin beagle

After banging my head against the wall with my hydraulic clutch doing the same as yours, it finally hit me...no not the wall. I never replaced the steel plates during any of my attempts at fixing my clutch. Visually they looked ok...a few showed a little bluing. I finally followed the manual and checked them for flatness. All but one were fine...just that one plate being a little bit out of whack wreaked havoc with the clutch. Replaced all of the steel plates and clutch works great.

Shadowbennie

July 02, 2020, 12:03:09 PM #26 Last Edit: July 02, 2020, 12:28:24 PM by Shadowbennie
Quote from: Screamin beagle on July 02, 2020, 11:12:43 AM
After banging my head against the wall with my hydraulic clutch doing the same as yours, it finally hit me...no not the wall. I never replaced the steel plates during any of my attempts at fixing my clutch. Visually they looked ok...a few showed a little bluing. I finally followed the manual and checked them for flatness. All but one were fine...just that one plate being a little bit out of whack wreaked havoc with the clutch. Replaced all of the steel plates and clutch works great.

That thought occurred to me - maybe the steels are warped, but visually speaking, they all look pretty good except for the (1) plate in the picture, where it looks pretty smoothed out, which is the only one of concern in my mind. But, I certainly can't hurt to get a plate of glass and check for flatness and probably sand the steels and fibers just to make sure. Thankfully, my company makes lighted mirrors, so bingo, found a 3/8" piece of plate glass.....let the fun begin!

Shadowbennie

Quote from: Screamin beagle on July 02, 2020, 11:12:43 AM
After banging my head against the wall with my hydraulic clutch doing the same as yours, it finally hit me...no not the wall. I never replaced the steel plates during any of my attempts at fixing my clutch. Visually they looked ok...a few showed a little bluing. I finally followed the manual and checked them for flatness. All but one were fine...just that one plate being a little bit out of whack wreaked havoc with the clutch. Replaced all of the steel plates and clutch works great.

Went through all of the plates on Thursday, checking flatness on a 3/8" of plate glass. I'm pretty sure a couple were on the razor's edge of the manual spec (.006") - but, I wanted to ride this weekend, so I buttoned it up after lapping all of the steels with some 320 grit on the glass. Left the fluid level *just* touching the basket - it was better, wouldn't drag nearly as consistently when it got hot, if at all.

Although I'm still getting the weird "freeplay" in the lever which goes away after a few seconds after shifts, and it's not in every gear, which is strange - so wondering if maybe my slave or master need to be rebuilt.

If I can scrape up enough coin (just spent a bunch of dough on suspension upgrades) I'll probably look at a new clutch pack from Alto or Barnett and see if that eliminates the dragging - maybe go back to a kit that uses the judder spring & spacer. If it doesn't then I'll consider the slave & master rebuilds this fall/winter.

fleetmechanic

We recently bought a 2018 police bike locally that was laid down on both sides late last year with only 2000 miles on it.  There was a pinhole in the clutch line where it got dinged by the engine guard so I replaced the line and then the master cylinder wouldn't draw or push any fluid.  Holes in the cylinder were clear. Put a rebuild kit in the master cylinder and no change.  Replaced the complete master cylinder/clutch lever assembly with a new one and works fine.  No idea what the real issue was.

Shadowbennie

Ugh - still dragging...again, and, still getting the slow return of hydraulic pressure to the lever creating virtual "freeplay". Will shift, then lever is sloppy for a few seconds, then the hydraulic pressure builds back and returns the lever to it's natural position.

I'm still at a loss - should I just get some replacement steels to eliminate the possibility of my current steels being warped, or does anybody have any insight into the slow return of the clutch lever - thus back to my original thought of a failing clutch master - I'm debating just rebuilding the darn thing, rebuild kits at cheap ($40), but I hate that I'm pretty much shotgunning parts at it.

kd

I think if it's returning slowly as you say, there must be a buildup restriction preventing the fluid from returning into the MC and equalizing the system. It could be the slave cylinder or the master.  I would expect the clutch pushrod has retracted because you don't say the clutch slips after a shift. That would indicate the slave cylinder is pushed back. IMO the most likely culprit is the master cylinder.
KD

Shadowbennie

Quote from: kd on July 14, 2020, 08:15:12 AM
I think if it's returning slowly as you say, there must be a buildup restriction preventing the fluid from returning into the MC and equalizing the system. It could be the slave cylinder or the master.  I would expect the clutch pushrod has retracted because you don't say the clutch slips after a shift. That would indicate the slave cylinder is pushed back. IMO the most likely culprit is the master cylinder.

Those are good points - seems that if the slave was failing, there should be throwout distance issues, and since it's not slipping, maybe the master cylinder piston is hanging up and takes time to return to position. I don't know if this is related to the clutch dragging though since my throwout measured up fairly well according to manual spec.

Two separate unrelated issues maybe? warped steels in the clutch with a sticky m/c? Do the fibers have a flatness spec as well or do those not matter as much when it comes to a dragging clutch?

kd

Yes, there is a chance that the clutch discs have suffered from dragging.  Both steels and fibers have to be true to release fully.
KD

Shadowbennie

Quote from: kd on July 14, 2020, 12:44:15 PM
Yes, there is a chance that the clutch discs have suffered from dragging.  Both steels and fibers have to be true to release fully.

Bummer, I was afraid of that - looking more and more like a new clutch kit and clutch master rebuild for me.....so is there a better option than the BDL (Energy One) extra plate kit? Alto carbonite? Barnett?

Shadowbennie

Welp, bit the bullet and got an Alto carbonite clutch kit, put it in this a.m. and gave it a test run- seems to be better, but haven't had the chance to get the plates nice and hot to see if it still drags. I will say the finding neutral after the short test ride was a breeze! Gonna give it a workout tomorrow and see what happens...

Shadowbennie

December 04, 2020, 10:06:20 AM #35 Last Edit: December 04, 2020, 10:17:31 AM by Shadowbennie
Hi folks, re-visiting this thread again - I rode out the summer with my dragging clutch after changing out my clutch pack to the Alto carbonite set, which then started slipping (even with using the heavy spring from the BDL clutch pack I removed), so went back to the BDL set and the creeping it had been exhibiting.

Now that winter has arrived, I want to try to solve this once and for all - here's the rundown of what has been done to date:

Currently have the original "dragging" BDL extra plate kit in.

- I rebuilt the clutch master cylinder in July - that solved the slow return issue with the clutch lever

- Removed BDL kit and with a 3/8" plate glass, sanded all fibers & steels using 220 grit - no change, then installed Alto kit, got slippage, so back to BDL

- Completely flushed clutch hydraulic fluid with new - have confirmed no air in system (have done this several times now.....ugh)

- Have verified that the throwout is within reasonable specs

- Have changed primary fluid a few times - first was running Formula +, then swapped to Spectro primary. Still dragging, so went with B & M trick-shift, no change. My final change for the summer was to a 10-40w dino oil in lieu of thicker formula + or Spectro primary fluid. It was still dragging with 10-40W oil near the end of the season.

As I see it, the items that I have not addressed to this point that could be potentially causing problems would be:

- Throwout bearing - if this is failing, can this cause clutch drag?

- Clutch slave cylinder - although the throwout measurements falling in spec contradict this being a problem source

- Clutch basket - I have not dusted the clutch basket tines with a file - but is there a reference as to what amount of wear could be a potential problem source?

-  Clutch hub - no noticeable damage or wear the last time I was in there to swap out the Alto clutch kit back to the BDL extra plate kit. plates installed smoothly

- Clutch pack - maybe the BDL kit is flat-out just warped and I need to buy another new set? However, if this is the case, I think this time I'll get a standard kit configuration that uses the judder spring and seat - the Alto kit made use of the judder spring and seat and had a better feel to it than the BDL extra plate kit.

I can certainly shotgun a new clutch slave at this thing, as they're only about $150 for a new slave assembly ($200+ for the Muller), but would prefer not to- just looking for feedback on anything I may have overlooked.

TIA!