Clutch slip EDIT Sorted!

[flatfour]

I think that I still have the set of friction plates that I removed from my 750 K2 when I bought it some three years ago. I changed them as a matter of routine rather than for a specific reason, as I had clutch slip on my previous K6 and thought that I would take care of a potential problem before it could arise with this bike.

If these are of use to you, I will check that I still have them (all parts that I keep are stored indoors in sealed plastic bags) and if you want to arrange for a courier to collect (from Norfolk) you are welcome to them.

[MrDavo]

Thanks for the kind offer flatfour, if I can't get the real thing or make the ones Ive got fit I will take you up on it and send a myhermes man to pick the plates up, I'll pm you if I need them.

Like you if possible I'd rather fit new. As all the CB750's on the road are all slowly consuming clutch plates it seems amazing that this is one of the parts that Honda can no longer be bothered with in the light of their previous support for life policy. Slivers have 3 plates, I'll email to see if they expect any more, ever. If they do expect some then flatfour's plates would keep me on the road, mine are definitely shot, comparing them with new.

Interesting James had the same issue. How hard could it be for pattern parts makers to just make them the same size as Honda did?

CMS' plates are also pattern, so they may well have the same issue. Z1 aren't replying to my emails, so its not looking good for a refund, in any event my duty, post office fee and carriage are toast.

Here's a snap of a Z1 plate not fitting:



It's hard to see, but look around the 2 o'clock position - in  the right place, but not going past the external band.

The difference is really small, about 1mm. The real hassle is that each plate has 12 tab, so 84 tabs to shave a bit off.

I'll see what DSS have to say, if 'no' I may try shaving down the tabs on one plate, to see how hard it is.

[flatfour]

I've checked and they are bagged up in the garage, if you need them. The part number on the invoice from DSS is 22201371000 and they are described as OEM Friction Plates

[MCTID]

Oooops......although it seems a bit daunting to tackle each of the 84 tabs......especially to remove 1mm from the diameter.......but if you can find a local Machine Shop, it would only take a few minutes for them to mount in a lathe and turn them to the required diameter all at the same time.........and probably cost you £20.

I had a problem last year with my Peugeot Rear Brakes.......to replace the Brake Hubs I had to destroy the Bearings..........new Hubs and Bearings weren't expensive but the Bearings needed to be Pressed into Hubs.........went to a local Machine Shop who had a stonking great Power Press......and 10 minutes and £20 later.....job was done. Happy bunny.

P.S. If you can't take accurate measurements of the plate and basket dimensions.....take the Clutch Basket (or the motor....or the bike) with you to make sure that you have to correct clearance after the plates have been machined......or you'll probably have to do it all over again. More ooops.

[MrDavo]

DSS tell me they will have the real thing in stock next month. In the meantime, in the absence of any reply from Z1, I'm clearly stuck with what I've got, and having bought new pates I would like to use them if I can.

I spoke to a mate with a lathe (and a bikeshop), who thinks mounting them in a lathe to remove metal from the O.D. would be a pain, but he has done a similar job to get pattern Suzuki plates to go into a banded clutch, exactly the same problem.

He suggests I have a go at fixing 2 or 3 plates together, using an original as a template, and having a go at removing metal from the tabs (I have a bench mounted rotary grinding wheel, and yes, I know that I have to be careful not to 'clog' the wheel when grinding soft metal). As long as they fit inside the band he doesn't think finish or balance would be an issue, so I'm minded to have a go at the weekend. If it works, job done, if not I still have a set of expensive pattern plates I can't use.

[MrDavo]

News from the front, all sorted, thanks for your help.

Saturday was spent mostly grinding 1mm from each of 84 tabs. I decided that while a machine shop could do a better job, eventually, and that really I should send them back to the USA because they weren't right, sod it - I want my bike on the road now, not another delay wasting time I could be out riding.

After doing the first plate I taped them together in pairs to save time. It still took me all day to get to this stage though, all back in and tightened up:



I had discovered that the concave washer was missing, so I got a new one, and a new tab washer, and tightened up the clutch nut with my new tool.

As well as plates and springs, I replaced the lifter plate which had the end of a tab snapped off in a previous life, it's well documented how to do this:



I haven't noticed less vibration, but it can't have helped the balance any as it rotated with a bit missing.

After finishing, testing and still finding getting into first a bit clunky, I did some reading and discovered I had been setting the cable wrong, and not leaving a bit of slack when doing up the adjuster at the clutch end. That made all the difference - I now have a one finger operation clutch, with the bite point where I want it. After years on Brit twins I cant believe how light the clutch is.

As proof of the pudding I went for a ride and thrashed her up the same hill, past Dovestones Reservoir and over the border into Yorkshire. No clutch slip this time, just howling HM300s and a big grin.

[Johnwebley]

   great news,

   I bet your still grinning after that ride

[K2-K6]

I think many people blame all sorts of things when the clutch on these doesn't work correctly.

As you've explained though when the parts are right and it's setup ok they do work really well,  they're quite a nicely engineered little unit.

Bike looks so nice out on its run,  well done with the perseverance to get it sorted as well. I'd have filed the tabs as well to set them up for a correct fit.

[MrDavo]

A rubbish photo, but here's Candy at our mission objective, Compo's Cafe in Holmfirth.



Cod, chips mushy peas, bread and butter and a pot of tea put the clutch under even more testing conditions going back up the hill....

BTW, I did file the tabs, as grinding them had left burrs to the tab edges. It didn't go back until it all moved smoothly.