2000 Concours clutch slipping

[Amdonim]

Title has it. Sold my Honda and bought a Connie about 6 weeks ago. My clutch suddenly started slipping a few days ago. Up until that it was fine. In the course of a day it went from only slipping at high rpms to pretty much slipping with anything more than 5% throttle. Leading up to this, I rode about 1500 miles over a weekend, no problems. Halfway through, I changed engine oil at my father's house. It was AMSoil synthetic MC oil. On the way back I got stuck in a traffic jam, lots of very slow speeds. It was hot, but the bike didn't overheat or anything. I'm worried all the low speed and starting/stopping may have damaged it. Today, as per recommendation of other site I flushed the hydraulics for the clutch. SC seems to have a slight leak, but i've ordered a new seal for it. MC seems to be in good shape. Any ideas what to do? I've never dealt with a bad clutch here so I'm pretty lost.

[ceemes]

First off, welcome to the Connie family. Both Johnj and I are proud owners and riders of older Connies, which are arguable the best Sport-Touring bikes of their era.

As for your clutch issue. Never had a problem with my clutch on the Connie and she has almost 200,000 kilometres on the clock. However, my old GPz1100 and both KZ550's (the KZ's were courier bikes, so got a lot of hard use) had clutch issues. From the sounds of it, you might just have worn out plates and need to replace them, much the same way you need to replace the clutch on a car with a standard transmission when it wears out.

However Johnj is much more knowledgeable when it comes to wrenching and trouble shooting Connies, so I will defer to his expert opinion when he pipes up.

[Johnj]

You are too kind ceemes, first off make sure the oil you used does not have any "Friction Modifiers" in it. From your describtion (after changing the oil, it's getting worse) that's where the problem started. If the clutch is contaminated you can try changing back to an oil with an API classification of SE, SF, or SG (the book). This may not work as you may have to change the oil several times to get it all out. You can take the clutch apart and replace the fiber discs, after all they're the part that's contaminated(the oil, with the evil Friction Modifiers in it, has soaked into the fiber discs). I use Shell Rotella T® 15W-40 in all my bikes now and have had many thousands of miles (on a bunch of UJM's) on it.

When you release the clutch lever hydraulic pressure is released. When you pull the clutch lever hydraulic pressure is applied.

[Amdonim]

The engine oil shouldn't be a problem, it was motorcycle oil, no friction modifiers. Checked it twice. I read a suggestion elsewhere that it might be blockage in the MC relief hole, causing pressure to not release fully. Sound plausible?

p.s. What is the function of the spring in the SC?

p.p.s. I thought I'd mentioned this before, but the slipping only starts once the engine is at operating temperature. For the first few minutes after start, the clutch sticks fine, even during WOT. Once it's hot, more than 5-10% throttle causes slipping, although it eventually catches.

[Johnj]

Posable, but not probable. Pull the clutch lever then release it. Can you pull it again?
The spring holds the piston against the pushrod.
I have spent much time in stop and go traffic, the only thing that wore out was my left hand.

[ceemes]

I have spent much time in stop and go traffic, the only thing that wore out was my left hand.

Don't I know that pain, Connies seem to have a heavy clutch. Best you have a strong left hand/wrist if you are doing much stop and go riding. More often then not, I take a chance and put it in neutral while waiting for a light to change and give my hand a rest. Dodgy I know, but I am left handed and need the silly thing to do most of my work.

[Amdonim]

Well it seems the Master Cylinder is failing. The push rod isn't fully returning. Ordered a MC rebuilt kit. Maybe this will solve the problem.

[Amdonim]

While I'm waiting on the kit to come in, is there anyway to get the slave cylinder apart? Can't pump the clutch lever, no fluid.

[Johnj]

You can use a vacuum pump to pull the brake fluid from the slave cylinder. Instructions are in the manual. You do have a manual?

[Amdonim]

Yeah. I left it in Houston and just got it in. The slave is empty already. The manual reconmends using compressed air to get the piston out. I don't have a compressor with a tank, could I use a small 12v compressor?