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Clutch slipping at 4K RPM full throttle. Do I need plates and springs?

lmckusic

lmckusic

Guest
Guest
I am asking for opinion or experience on which clutch components to replace.

It feels to me like the clutch is slipping on my Connie C-10 when I give it lots of throttle. The first time I noticed it, I was going through an intersection in second gear. I thought the rear tire was possibly slipping on the light sand in the intersection. The next time I noticed it was hurrying up to pass three cars at 35 mph. Giving the bike a big handful of throttle, it takes off fine, and at about the torque peak the engine rpms seem to go up and the bike isn't moving out like I expected. There is no time to look at the tach as the bike is going way over 35 and the problem is to immediately slow down after the pass is complete.

Reading the COG posts, I see much more about the clutch springs and no posts at all about replacing the clutch plates. My bike is a 2000 vintage, it did have the clutch slave cylinder replaced, and it has 71,000 miles.  And I have bought the Murph's clutch spring kit.
 

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Lee,
Most likely it is NOT the clutch plates or discs, it will be a star spring issue or a Slave/master cylinder issue. This clutches just don't quit like that. Many have racked up over 200K on them. Exhaust all other possibilities before the clutch replacement as it is not a simple swap. there is an "installed height" measurement that MUST be adhered to or the new clutch will not function either.
Matt
 
I see you had the slave replaced.  How long ago was that?  Did they flush and thoroughly clean the master cylinder at the same time?  When you look at the sight glass in the clutch reservoir, does it look dark or is it clear?  It doesn't take long for new brake fluid in the clutch system to start looking like coffee (about 1 year).  This could be as simple as a gunked up master cylinder.  Also, I have to ask this because I've done this myself.  The engagement/disengagement point on these bikes is at the very end of the clutch lever stroke.  Any chance you have a finger or two resting on the clutch lever during these throttle roll-ons?  Have you tried snapping the throttle open under a more controlled situation?
 
Any chance you are using some ultra slippery synthetic "energy conserving" engine oil?? Wet clutch system won't like that.
But, you are probably aware of that already.
 
jettawreck said:
Any chance you are using some ultra slippery synthetic "energy conserving" engine oil?? Wet clutch system won't like that.
But, you are probably aware of that already.
Click to expand...

You know, I've only ever heard warnings about this. I know there are cases, but I wonder if there are thousands of people that just use whatever oil without trouble. People coming from HDs that don't know any better maybe (since their transmission/clutch are separate from the engines). Crappy thing is even the cheapest crap has energy conserving additives these days. Gotta go diesel for cheap oils.
 
I actually had my clutch do this and the only problem was the clutch lever was not rotating freely and needed cleaning and lubing.  It was not letting the MC fully release.
 
You can test for clutch slip easily.
Get into 6th gear, at around 30Mph.
Pull the clutch in, give her about 6000rpm and dump the clutch hard.
If it slips you'll know.
 
Or put your front wheel against a concrete wall or such and egage the clutch slowly, give it a LITTLE throttle.  if the engine dies, your clutch is good, if the RPM goes up, she's slipping.

Another possibility is worn/stripped splines in the rear wheel drive plate, which is has been known to happen  with these bikes.  If you do the above test, and you heard grinding noise, that could be it.  Remove the rear wheel and pull the drive plate out of it, and check to see if your splines are worn. 
 
I did have to replace the springs in the clutch somewhere around 200k miles/14-15 years old. IIRC, they were about .125" under spec or a bit more for some. The fibers still had 30% left.
 
The master cylinder has a tiny port in it that can become clogged. When clogged, the hydraulic system will retain some pressure, in turn putting pressure on the clutch, allowing it to slip.

That might not be your problem, but that's where I would start.
 
drumstyx said:
jettawreck said:
Any chance you are using some ultra slippery synthetic "energy conserving" engine oil?? Wet clutch system won't like that.
But, you are probably aware of that already.
Click to expand...

You know, I've only ever heard warnings about this. I know there are cases, but I wonder if there are thousands of people that just use whatever oil without trouble. People coming from HDs that don't know any better maybe (since their transmission/clutch are separate from the engines). Crappy thing is even the cheapest crap has energy conserving additives these days. Gotta go diesel for cheap oils.
Click to expand...

I lost my clutch to me using the wrong oil and there is no amount of changing to the correct oil and multiple oil changes  that can fix this.  If you put the wrong oil in most or many may not even notice the problem unless you do some wide open throttle.
The remedy was to replace the clutch plates so I ordered a kit. The problem with the kit was my stack height was  wrong  (which drastically effects the function of the slipper clutchso I would have had to order shims (more parts to order).
In the end I ordered a used complete  basket/clutch pack from Ebay and returned the kit. Problem resolved.
 
The slave cylinder sometimes corrodes and doesn't let it work correctly.
if that's the problem, remove the slave cylinder and piston, lightly sand the ID of the cylinder or use a Scotchbrite pad.
Then reassemble...

Ride safe, Ted
 
Daytona_Mike said:
drumstyx said:
jettawreck said:
Any chance you are using some ultra slippery synthetic "energy conserving" engine oil?? Wet clutch system won't like that.
But, you are probably aware of that already.
Click to expand...

You know, I've only ever heard warnings about this. I know there are cases, but I wonder if there are thousands of people that just use whatever oil without trouble. People coming from HDs that don't know any better maybe (since their transmission/clutch are separate from the engines). Crappy thing is even the cheapest crap has energy conserving additives these days. Gotta go diesel for cheap oils.
Click to expand...

I lost my clutch to me using the wrong oil and there is no amount of changing to the correct oil and multiple oil changes  that can fix this.  If you put the wrong oil in most or many may not even notice the problem unless you do some wide open throttle.
The remedy was to replace the clutch plates so I ordered a kit. The problem with the kit was my stack height was  wrong  (which drastically effects the function of the slipper clutchso I would have had to order shims (more parts to order).
In the end I ordered a used complete  basket/clutch pack from Ebay and returned the kit. Problem resolved.
Click to expand...

In my experience with Conni clutches, I have found that if the fiber plates has been contaminated, or toasted from abuse, only the fiber plates need to be replaced.
If you purchase OEM fiber plates, they are very precise, amazingly so, and unless the steel plates are destroyed, which I have never found... they should be scrubbed and re used.
This will keep the stack height almost perfect.... and no stack variance will be resultant over the original spec.
Pre soak the fiber plates in a ziplok bag of the same engine oil you plan to use for filling, and go for it. Also note to refer to the fsm for correct fiber plate placement, the outborad fiber get shifted to the captive groove in the basket for proper function.

I've done over a dozen star spring replacements for myself and others, and have yet to have to buy a steel plate... ymmv.

NOTE
I always use the OEM fibers, and never suggest using aftermarket (Barnett or others)
They are not made the same, or have the same consistant dimensions and tolerance of OEM
 
Thank you for a bunch of good comments about understanding what might be clutch slip on the Connie.
Lee
 
LeeM said:
Thank you for a bunch of good comments about understanding what might be clutch slip on the Connie.
Lee
Click to expand...

1) broken star spring(s), broken pices of tip preventing complete friction plate contact
2) incorrect oil
3) Clutch slave cylinder gacked up, needing a rebuild kit, including the piston spring....
4) flush and bleed of master cylinder, and possible rebuild,
5) clogged return port on master cylinder
6) worn clutch lever bushing, or lack of lube on it

7)  a bunch of miles and abuse.

Oh, and as I noted, and you said you bought a murph clutch spring kit... the outer friction plate is not correctly clocked and positioned, and was simply stacked as were.the others... this would surely cause the issue...

Note the position of the outer plate, thanks to Davida, that posted this in another thread about a different problem, but it was perfect timing for use here to show plate positions... :great: :great:


7FBB0C72-06A1-41A2-897A-8CF2C4762EE5_zpstn49kn90.jpg
 
connie_rider said:
The slave cylinder sometimes corrodes and doesn't let it work correctly.
if that's the problem, remove the slave cylinder and piston, lightly sand the ID of the cylinder or use a Scotchbrite pad.
Then reassemble...

Ride safe, Ted
Click to expand...
This post helped me get my bike back up and running. I flushed the brake fluid for the clutch and rebuilt the slave cylinder. Also, I made sure to clean up the master cylinder reservoir since it was nasty. Thanks!
 
jkmk168775 said:
This post helped me get my bike back up and running. I flushed the brake fluid for the clutch and rebuilt the slave cylinder. Also, I made sure to clean up the master cylinder reservoir since it was nasty. Thanks!
Click to expand...
Glad the information got your bike up and running. I see that you are on " free limited trial", the number one reason I initially became a paying member was due to the amount of information that I received from this site. Heck, I think if I just drive by a dealership it costs me $37.🤣
Please consider becoming a full member.

Ride safe and stay focused
Dale
 
I knew a guy that went so long without an oil change, that the clutch would slip. He changed the oil and it quit slipping.
 
Pr356 said:
Glad the information got your bike up and running. I see that you are on " free limited trial", the number one reason I initially became a paying member was due to the amount of information that I received from this site. Heck, I think if I just drive by a dealership it costs me $37.🤣
Please consider becoming a full member.

Ride safe and stay focused
Dale
Click to expand...
I second the opinion. Money well spent. Well spent, indeed.
 
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