Post by: MrDavo on February 07, 2016, 08:12:18 PM
When I stripped the clutch, I pulled the plates apart, and each steel plate had a 'photo' of the friction plate it had been in close company with for god knows how long. I cleaned up the steel plates, and oiled everything before reassembly, as per the manual. Maybe I over oiled, I don't know.
The clutch has worked fine since, but on a ride out today, I gave it full beans to pass a car, going uphill, and the clutch suddenly slipped. backing off a touch got the drive back, but I got it to do it again later, same thing, WOT and a high gear.
It seems to me that if this happens solo, then 2 up with camping gear is going to be a problem.
Do you think my plates are shot, or could cleaning the plates or adjusting the springs get me my drive back 100%?
Post by: hairygit on February 07, 2016, 08:26:45 PM
Sent from my X5 using Tapatalk
Post by: Bryanj on February 08, 2016, 06:26:44 AM
Post by: MrDavo on February 08, 2016, 10:09:06 AM
The cross shaped lifter plate has a small piece missing at the end of one of its 'ears'. It cant affect the operation, but I'm wondering if it contributes to the 'buzz' that blurs the mirrors at speed as the clutch will be out of balance as it spins.
Post by: MrDavo on February 10, 2016, 05:18:52 PM
Lets see what takes the longest, I'm not dismantling the clutch (or using full throttle) until I have all the bits.
Post by: 750rideruk on February 10, 2016, 05:50:09 PM
don't ask me how I know this!!!
Post by: tom400f on February 11, 2016, 11:02:29 AM
Post by: ST1100 on February 11, 2016, 12:13:57 PM
There are various reports of "modern" oils causing clutch slip on these bikes.I'd limit this to modern car-oils, as bike specific full synt ones have friction additives added...
Post by: MrDavo on February 11, 2016, 03:25:13 PM
Are you running mineral oil, or at most semi-synthetic?
Old school Halfords Classic Multigrade. But lets not start another oil thread. I take the point about modern oils, apparently if I put synthetic in my air / oil cooled 911 bad things would happen and it would try and escape through the oil seals.
Post by: MrDavo on February 19, 2016, 02:47:01 PM
I just went out for a ride, and its noticable that the bite point isn't where it should be, almost the lightest touch of the clutch lever will disengage it. 2 up, a good twist of throttle on the bypass and it slipped. The clutch is as light as any i've tried (amazing compared to a 750cc Brit) so I dont think the cable is binding, but that adjustment has gone somewhere.
No doubt all will be explained when it comes apart, what determines the bite point though? I remember having to set the adjustment of the cluch lifter arm, could this have gone awry?
Post by: MrDavo on February 20, 2016, 10:44:19 PM
The day started badly, the postman plays 'knock and run' and just leaves a card, despite me buying an industrial strength doorbell just for him. Get to the sorting office, pay £5.53 VAT plus an £8 fee to the Royal Mail. :(
Get in garage, strip clutch, try to refit with the new plates from Z1, can't. The ad says they fit http://z1parts.net/clutch-friction-plate-honda-early-cb750 the number is correct from my parts book, but the ears are 1mm too wide and wont pass the band that goes around the basket to stop it spreading. I could grind them but there are a lot of ears, it would be rough, and why the &*(% should I have to?
I waited nearly two weeks for these to show up, now what do I do?
I'd like to say that's the last time I use non - Honda parts, but D Silver still has just 3 plates in stock. :( The only OEM ones on eBay are in the USA of course.
Post by: hairygit on February 20, 2016, 11:24:38 PM
Post by: MrDavo on February 21, 2016, 12:45:22 AM
The plates I ordered were listed as equivalent to 22201-300-000, my parts book thinks that's right for K1 and K2.
If I have a later clutch than K2, quite possible, can someone suggest a part number for the friction plate to fit? Any way to tell? I'm loathe to order pattern plates from say CMS, they may very well be from the same source. The only other course is to start grinding ears!
Post by: JamesH on February 21, 2016, 06:46:10 AM
Post by: flatfour on February 21, 2016, 09:52:44 AM
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.
Post by: MrDavo on February 22, 2016, 04:07:03 PM
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:
(http://i34.photobucket.com/albums/d144/roycropper/IMG_0119.jpg)
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.
Post by: flatfour on February 22, 2016, 08:36:59 PM
Post by: MCTID on February 23, 2016, 11:38:04 AM
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.
Post by: MrDavo on February 24, 2016, 10:45:49 AM
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.
Post by: MrDavo on February 29, 2016, 03:46:46 PM
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:
(http://i34.photobucket.com/albums/d144/roycropper/IMG_0834.jpg)
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:
(http://i34.photobucket.com/albums/d144/roycropper/IMG_0833.jpg)
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.
(http://i34.photobucket.com/albums/d144/roycropper/IMG_0841.jpg)
Post by: Johnwebley on February 29, 2016, 08:32:34 PM
great news,
I bet your still grinning after that ride
Post by: K2-K6 on February 29, 2016, 09:40:18 PM
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.
Post by: MrDavo on March 01, 2016, 12:38:44 PM
(http://i34.photobucket.com/albums/d144/roycropper/IMG_0142_1.jpg)
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.