docc

Four "command" cylinders on hand (thanks, Andy York!) to consider. As well as square section and round section O-rings in the best-guess sizes I posted. (rendered in Nitrile or Buna-N). Of course, the Nitrile/Buna-N will not work and the sizing does not appear correct either. These are only observations . . .

Honda CBX 1978-1982 came first. Laverda also did a magnificent job of copying the early Honda 305 motors to develop their 750 twins. Gorgeous motors!

Love the John Player-looking black and gold!

The Good Guzzi Fairy has surprised me with a pair of clutch slaves to consider. I suppose I'll inspect the seals in the new one and see if the shape and measurements make sense. Then install the used one and give it a go . . .

Short answer? nope. I can't be sure of the measurements or shape. Thanks, man. It's just I've lost confidence that this is the actual problem. Time to steel myself to the clutch inspection. If it checks out, I'll take you up on the offer! Thanks, again, to everyone for the discussion. I really don't think my measurements are valid on the seals.

As luhbo has pointed out, the chance the slave is my problem is dubious at best. Whether we can source a replacement for the NLA Grimeca V11 slave cylinder, or rebuild seals, remains to be seen. I've exhausted my resources in that regard. More likely, one or more of my clutch discs have failed. Well, nuts.

This is Grimeca's contact page. I have no idea what to do with it: http://www.grimeca.it/en/contacts

Thanks for the encouragement, guys. I have to admit to feeling pretty bummed at the Sport being down and no visible progress in sight. I try to take heart in the words of Thomas Edison,

Introducing beer to the discussion is certainly helping to stave off my creeping discouragement in the whole affair.

I'll get Grimeca on my to-do list. At this point, I've lost confidence the flat seal is square, or that it can be measured and built. So far I've only managed to chase down a few dead ends. Thanks for the continued input.

For now, I'm carrying on with Andy's clutch slave thread. One main reason is for our community to collectively pursue a reliable solution to the now unavailable part. In the event that it turns out to not be the source of my failure, I'll bring the discussion elsewhere. At that point, I do hope we will have documented a solution to the NLA clutch slave for those who may need it in the future.

I rebuilt the master cylinder at 62,000 miles/ 100.000 km for a broken internal spring (currently ~103,000 miles/ ~167.000 km). At first, I thought this might have occurred again, but the lever moves and returns normally with no fluid in the system. So, it is not likely the spring like before. Thinking it could be the master cylinder seals at fault, I have obtained a rebuild kit for it just in case. My plan was to address the slave first, then the master cylinder before resigning myself to remove the gearbox and obtain the necessary clutch parts and replacement flywheel.

It doesn't seem like weak clutch springs would present such a sudden change. Ariete replied they have nothing for this Grimeca cylinder.

I'm finding this out. I'd like to get the hydraulics back together soon. If the trouble persists, I will have to take a look at the clutch, input shaft, and flywheel. I feel certain mine is well knackered from holding the clutch in at stops all these years.

Well, something's wrong. I am just trying to work through the parts systematically. I thought the slave could use some attention by this point. We shall see, I suppose . . . P.S. - It is, of course, the scary V11 flywheel that has all of smack of hypochondaic internetitis.

I'll go back to my local supplier later this week. They spec'd the build (in Nitrile) for about $13US each/ minimum of ten, but I'll have to see if they can have them built in EPDM. In the meantime, I've contacted an EPDM supplier online as well as Ariete in Italy. It just seems like the kind of thing that ought to already be in a bin somewhere, waiting to get bagged and shipped . . . Thanks, everyone for the community effort! We'll get this figured out! It'll be one for The En-psycho-pedia of Compatible Parts.

Yeah, I called Harper's two days ago: NLA, not in stock. Moto International also lists the part online, but emailed me shortly after my order to advise the same.

Everything at Motion Ind. looks to be inch measure, and no square section.

Looks like Silicone O-rings are compatible with brake fluid, but have "low tear resistance and high coefficient of friction." Also, I only see fractional measures (no metric) silicone O-rings at McMaster-Carr (?) "Silicone compounds are very clean and are used in many food and medical applications because they do not impart odor or taste. Silicone compounds are not recommended for dynamic O-ring sealing applications due to relatively low tear strength and high coefficient of friction. Silicone is resistant to hot air, ozone, UV radiation, engine and transmission oils, animal and vegetable fats and oils, and brake fluids." (https://o-ring.info/en/materials/silicone--vmq/?gclid=CjwKEAjwqIfLBRCk6vH_rJq7yD0SJACG18frNSY_FySPui6fJXq9hwsnFG4bfiZXzNSbtHtuH8V2ORoCptvw_wcB) Will we be correct in declaring that the correct compound for this application is EPDM?

Definitely. Is there a part number on the slave? No part number on the Grimeca slave cylinder. There is an outer round section O-ring that is likely the "seal". I'm trying to rule out the inner "flat" O-ring. Again, my failure could be (or could be exacerbated by) the worn flywheel [or input shaft as Chuck noted earlier], but I'm (obviously) hoping for a simple O-ring solution.

The eccentric doesn't offer much adjustment to the pedal position. Maybe something like LuckyPhil has done with his shift lever would give you what you're looking for: http://www.v11lemans.com/forums/index.php?showtopic=19547

Great thread, here, by LuckyPhil on V11 Shift Improvement with lots of photos and good methods: http://www.v11lemans.com/forums/index.php?showtopic=19547

The flywheel wear is a definite concern. I *thought* I was going with the simple solution first. Another high(er) mileage V11 we know of just needed a clutch slave replacement. The failure doesn't *feel* mechanical like the clutch discs popping back out of the flywheel grooves. (But, yeah, I am totally putting off the big teardown. "Some people" seem to take these things apart like Legos ) So, right, the Grimeca made V11 clutch "command" cylinder is No Longer Available.

It's not that it leaks, the clutch won't always re-engage; feels like the piston is sticking.