Author Topic: Primary Sliding Plate With Integrated Oil Seal  (Read 945 times)

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Re: Primary Sliding Plate With Integrated Oil Seal
« Reply #15 on: 22.09. 2018 22:46 »
I think it was the semi-unit (and some singles) that had a clutch cover designed to keep oil out as much as possible.
Check!

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Re: Primary Sliding Plate With Integrated Oil Seal
« Reply #16 on: 22.09. 2018 22:56 »
just to clear up RD fella, so if we had a stock of old corked plates things would be ok, or if we collected good shampers corks we could re cork  all the plates{as I did two chainwheels} and bobs ya uncle, so it must be the newish bonded plates that are sticking and tend to slip when the clutch case has got its oil in for the chain lube

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Re: Primary Sliding Plate With Integrated Oil Seal
« Reply #17 on: 23.09. 2018 21:07 »
G'day fellas.
Modern clutch material is designed to run in oil. New Surflex plates are OK with oil. BUT car type oil (GTX, Helix etc) with friction modifiers will make it slip. Use either motorcycle oil (Castrol Active 4T ect) or F type ATF.
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Offline RDfella

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Re: Primary Sliding Plate With Integrated Oil Seal
« Reply #18 on: 28.09. 2018 16:52 »
Maybe you guys have better luck than me. I can only speak from experience and over the years I've had many old British motorcycles (Triumph, BSA (mainly) Ariel, James, Velocette, DOT etc) and most if not all of them had a slipping or dragging (sometimes both) clutch when oil got onto the plates. The only exception has been those designed to run in oil - eg the Honda Firestorm - and those with all-cork clutches such as the James and DOT. In fact cork clutches are likely to burn if run without oil. If the non-cork clutches worked with oil, why did BSA go to the trouble of fitting a steel bowl over some of them to keep the oil out?
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

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Re: Primary Sliding Plate With Integrated Oil Seal
« Reply #19 on: 28.09. 2018 21:08 »
G'day RD.
Our clutches aren't swimming in oil like modern wet sump bikes (my CB1100F slipped but due to the extra HP I built in). They should be OK if the springs are done up even and tight enough. The amount of oil should only just be touching the bottom run of the chain and a non friction modified oil.
My plunger has a cover over the clutch and many times over the years I have found oil inside the cover but the clutch didn't slip. The only time it did slip was when the motor wet sumped and put an extra liter of highly friction modified oil into the primary.
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'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, .
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Muskys Plunger A7

Offline RDfella

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Re: Primary Sliding Plate With Integrated Oil Seal
« Reply #20 on: 29.09. 2018 20:44 »
My position throughout this debate has been quite simple: why risk a slipping / dragging clutch when there’s no need? Our rear chains don’t run in an oil bath yet last many thousands of miles, and a properly lubricated primary will last 3,000 miles plus before it needs re-lubrication. With the limited mileage most of us do, in my view that’s quite acceptable. And no oil dripping on the floor! Only two of my bikes have oil in the primary – the Honda (because there’s no option) and the DOT, because the clutch is cork and needs oil (when there’s any left after leakage).
For example, my vee twin M21 runs a dry primary. I boiled the chain in grease – something I got in the habit of doing when the bikes I raced in the 60’s all had uncased primaries – and all I do is give it two squirts from an oil can through the inspection hole every 500 miles or so whilst the engine is running. So far it’s done around 5,000 miles and I’ve yet to take the chain out and re-lubricate. And I know it’s not worn because the slack hasn’t changed.
My aversion to putting oil in primaries (as I alluded to in an earlier post) came about with a Triton I built. Every few days the clutch would slip on kickstarting sufficiently to prevent the mag producing a sufficient spark to start (OK, it had high comp pistons). So every few days it was primary cover off, wash clutch plates in petrol, re-assemble - and add oil. I soon learned to leave the oil out.
Leaving aside the smaller bikes with Villiers engines and cork clutches, most of our older British bikes have dry clutches, yet run in an unsatisfactory environment because there’s a need to lubricate the chain. All I’m saying is that for our limited recreational mileages, it’s not necessary to run that compromise.
To those who say the problem is the grade of oil, I concede you may have a point. But back in the days when I rode more than now, you used what you could get. Multigrades were yet to be invented and automatic transmission oil was an exotic item known only to the upper-classes and available from your local Jaguar / Bentley dealer. Us lesser mortals used straight 20 (when we could find it) or otherwise whatever came to hand. Maybe a transmission oil or similar would fit the bill but, having found a solution that solves the problem for me, I’ve now been a convert to dry primaries for several decades. No need for fancy oil seals and no more mopping up oil from the floor!

If you run oil in your cases and it doesn’t affect your clutch or leak all over the floor, then keep doing it. All I can say is, you’ve been luckier than me.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

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Re: Primary Sliding Plate With Integrated Oil Seal
« Reply #21 on: 29.09. 2018 22:05 »
was that a rant *eek* well my beezer has oil in the primary that doesn't leek out, maybe because its put together well, I went on a good thrash Thursday over snake pass and made her have it as I do often, the only oil I could see when parked up over night was the breather mist and a sweat about 2mm long on part of a rocker gasket. she never slipped even topping 6000 rpm  in first to third and even grabbing a handful in 4th at over 4000 rpm and found neutral no problem at a standstill , maybe my profession should be 6 spring clutch technician and pub p*ss head solutions LTD *beer* *countdown* , I like oil in mine because I don't plod about and without it the chain would get too hot for my liking. the corks don't swim in oil like some japanese bike clutches do, on a strip down I see a bit of grease thrown from the caged ball race and a trace on the corks that might come off on the thumb if rubbed hard, I never have burnt one out but then again I don't do 1 in 3 hill starts two up towing a notrun *fight* *whistle*