[StraDuc]

So I finally got to take the new to me 900SS to some proper roads up in the Driftless region of SW Wisconsin this weekend. While wandering around on the county alphabet roads in the region I found the perfect road for a Super Sport as evidenced by the road sign... I sadly later learned that it was named after the V Twin engine manufacturer in Viola rather than the one in Bologna.

After about 150 miles of delightful corner carving I noticed the gearbox becoming more crunchy feeling on shifts and the clutch lever having more and more free play before disengaging. Also neutral became more than the usually hard to find then became impossible. The lever would come half way to the grip without doing anything. I managed to nurse it back to the motel and I was riding solo and there is no cell phone service in that area so I could call for help so I was lucky it held out. I had not abused the clutch nor was the fluid level lower than when I started the ride. I just changed the lines to Venhill SS lines about 300 miles back but I can't see how that would affect the clutch operation unless leaking...which they aren't. And I would think if there was air in the line that would have shown up much sooner after the line change. So is perhaps my original clutch slave packing it in at 8800 miles? I think it could only be the master or slave and the slave cylinders are well known slackers it seems, but I don't know the symptoms of the slave giving up. I just got home (luckily I hauled the bike up there in my truck so I was able to get back home) and I will start looking for the issue this week but I wanted the opinions of the Masters. I suppose the first thing to check is to remove the clutch cover and confirm it isn't moving far enough to disengage? Then the clutch stack height? Then...??

Oh and I will confirm what all of you long time SS riders already know... what a great twisty back road bike this is. I think it's the most fun bike I've ever ridden and I started riding in 1965-ish.

Thanks for any knowledge shared.

Terry

 

[rennsportmotorrad]

Well my thoughts are this--if it was working well before it started to fade then I would first just because its easy bleed the clutch again-I doubt this will solve the issue but it's easy to rule this out. again if everything was fine before I doubt your clutch stack height is the issue unless you smoked the clutch which I doubt you did--look at the master cylinder carefully with a light where the lever moves the piston-do you see and fluid in there -leakage etc-if not go to the slave cylinder remove the slave cylinder and look and see if you can see brake fluid on the inside where the piston rides inside the cylinder. I'm no Ducati expert but my guess is the slave cylinder is where your problem will be found. but check everything else out it will take no time to do and it rules out those

 

[Iwannaduc]

While wandering around on the county alphabet roads in the region I found the perfect road for a Super Sport as evidenced by the road sign... I sadly later learned that it was named after the V Twin engine manufacturer in Viola rather than the one in Bologna.

Nice!! After seeing the picture, I'd probably have assumed as you did, that it stood for super sport!! Who'd a thunk it was for S&S???

I think it could only be the master or slave and the slave cylinders are well known slackers it seems, but I don't know the symptoms of the slave giving up.

Well....now you do. If it were the master cylinder (and I'm not saying it couldn't be) you'd see it leaking either at the plunger seal or the crushwasher/banjo.

The slave cylinder can leak and not ever be seen leaking. It may not leave any evidence behind that it is. Of course, it can be painfully obvious too.

In some circumstances, it can leak and the "bellows" that resides between the clutch slave and the opening in the lay shaft will contain the leak for quite a while. When it finally begins to leak from there, it will drip down onto the chain and/or in the countershaft area.

When it leaks down onto the chain, you ride and all the evidence of leak (EOL) flings off the chain. When it leaks into the countershaft area, you don't see it because a) the EOL is behind the countershaft cover and/or b) the build up of chain lube and grime behind the cover acts like a sponge.

Don't ask how I know all this.

Suffice it to say that if your particular bike was not ridden regularly (and at 8800 miles from the mid 1990s I'd say it hasn't)and you still have the OEM slave, then the slave cylinder is likely the culprit.

You can rebuild the OEM slave cylinder...pretty sure there are kits available from Gotham cycle. Or, you can order yourself a spiffy new slave cylinder (recommended) from any online retailer of such cylinders. Oberon is popular but my choice is EVR.

Both are available in the same colors and offer a similar amount of lever effort reduction. They are also similar in price.

A failing clutch hydraulic system is indicated by exactly what you describe. Increased difficulty in gear selection as well as finding neutral. It will get progressively worse until it is impossible to get into gear at a stop.

Stack height issues would reveal themselves in a slipping clutch, indicated by increased rpm on throttle, without matching increase in road speed.

Hope all of this is useful information for you.....sean

 

[belter]

you say the fluid level hasn't dropped? so realistically there's no leak. if it was just out of fluid you'd see it, and it'd probably be leaking from the slave. which has been said above is not always apparent.

what sort of levers are on it? as in, can the pushrod adjuster wind itself out giving lots of freeplay? some do.

if you pull the lever several times quickly does it pump the pressure up?

lean the bike over to the right, turn the bars to the right so the lever is the highest part of the master and work the lever several times - slow, fast, short, full pulls - to see if you can get any air to come up into the reservoir.

remove the clutch cover and see if the freeplay corresponds to the complete assembly moving out - spring caps being the most obvious. if the spring caps are moving with the lever, the nut is lose or there is a heap of wear behind the big star washer. i put 3 extra washers in one last week.

if it had a pack issue or warped steel plates, etc, the lever feel would not have changed as such.

 

[StraDuc]

Thanks for the ideas guys. Sadly I have to work today but I'm off tomorrow and Wednesday and I will be checking out the clutch armed with your suggestions. I do however have a feeling there is an Oberon slave cylinder in my near future.

I just remembered and I have to wonder if disturbing the clutch slave caused it to go South since I had installed a LT Snyder case saver just before the trip. That requires sliding the slave away from the engine to slip the saver into position. I know when I have to do plumbing on my house it's never just the section you repair, there's always a new leak that forms somewhere else along the line after you loosen and tighten a joint.

 

[Jetta03]

Totally possible that removing a ‘marginal’ slave cylinder introduced some air. I rebuilt my slave cylinder recently and if I removed it from the engine case pre-rebuild as you describe I’d have to re-bleed it.


Sent from my iPhone using Tapatalk

 

[Strega]

My guess is that some debris is partially blocking the replenishing port in the master cylinder.

When you release the lever, fluid is not refilling the cylinder, causing symptoms similar to no clutch fluid in the reservoir.

(Similar problem with the brake master cylinder)
https://www.ducati.ms/forums/57-supersport/723859-strange-front-brake-problem.html
https://www.ducati.ms/forums/57-supersport/723859-strange-front-brake-problem-4.html#post7006759

 

[belter]

My guess is that some debris is partially blocking the replenishing port in the master cylinder.

When you release the lever, fluid is not refilling the cylinder, causing symptoms similar to no clutch fluid in the reservoir.

(Similar problem with the brake master cylinder)
https://www.ducati.ms/forums/57-supersport/723859-strange-front-brake-problem.html
https://www.ducati.ms/forums/57-supersport/723859-strange-front-brake-problem-4.html#post7006759

i'm seeing a lot of this these days. you can pull the 90 degrees plastic elbow out with some pincer pliers and then i run a 0.6mm drill bit through the hole.

 

[StraDuc]

i'm seeing a lot of this these days. you can pull the 90 degrees plastic elbow out with some pincer pliers and then i run a 0.6mm drill bit through the hole.

So if I am understanding you correctly Belter that 90 degree plastic elbow is just a friction fit in the top of the cylinder? And it will just push back in without leaking after the replenishing port is reamed clean? And the replenishing port that needs cleaned out is right below the elbow opening hole? And perhaps a piece of .020" safety wire which I just happen to have a roll of (0.6mm drills not being easy to source here in 'Merica...) could be used to ream it out? Excellent news! I thought to get inside to clean it out I would be needing to remove the cylinder from the clip on and disassemble the cylinder, and pull out the piston and blow a bunch of compressed air in there and then get a rebuild kit (if it exists) so it could be reassembled... at which point I might as well just replace the cylinder with a new one like I did with the DOA rear brake master. It appears I have a new plan of attack for tomorrow. But I do have a black Oberon slave cylinder on the way just in case. Thanks!

 

[belter]

the elbow is held in by a rubber barrel thingy. you can pull it out and push it back in with some fiddling. fluid will spill. lever the rubber out and you'll see two holes. small one closest to outlet is the compensating port.

that's just a guess as to what may be wrong with it. if you can see the fluid level in the reservoir rise when you pull the lever in (very slight) then it's ok.

 

[StraDuc]

Result!

So as per Belter's info and Strega's hunch I sucked the fluid out of the reservoir with my vacuum bleeder and removed it. And I pulled out the plastic 90 degree elbow (with difficulty) and then the rubber plug. I didn't see anything amiss but I cleaned out the opening and poked around in the two ports with a piece of safety wire. I didn't feel like it pushed anything out of the port. I reinstalled the rubber plug and blew some compressed air (at about 30 PSI) into the cylinder with the lever pulled in then put it all back together, refilled the reservoir and hooked the vacuum bleeder to the slave bleed valve. I sucked 5-6 reservoir's worth of fluid thru and buttoned it up. And it appears to be resolved. Lever feels firm and "normal". It was into rush hour by the time I finished so I didn't want to take it out for a spin to check it out but I'll do that tomorrow. I don't know what the issue was, maybe a piece of detritus, maybe just air after all, but it seems to be fixed and I'm a happy camper. Now I wish I was back in S.W. Wisconsin... or Northern California.

Tip: it is much, MUCH easier to get the plastic elbow back in if you install it into the rubber plug BEFORE you install the rubber plug in the top of the master cylinder. I wasted about 20 minutes trying to install it with the rubber back in place. Pulled the rubber out, installed the elbow into the rubber and reinstalled the rubber in about 2 minutes.

Thanks to everyone for the insight.

Terry

PS-The cheapo Harbor Freight air compressor powered vacuum bleeder I have makes bleeding the line a real piece of cake. Highly recommended especially if you work alone.