C11 Clutch Slip

[scifi]

Hi Guys, I just found that my C11 clutch slips when I try kick starting.   The compression does not leak away, so I cannot force the engine over TDC.   The original crankcase oil was about a pint of very thick black oil, which I replaced by 1/3 pint of 10/30.  The clutch cable is loose so no problems there.   Is there an easy solution..?   
I find it strange that there is only one friction plate in the clutch pack, could I add more, as there is space on the basket..?

[scifi]

Having stripped the clutch down, I think I have found out where the excess oil came from..  It had wet-sumped and dumped all the oil-tank full into the crankcase, and then into the chaincase.   I emptied it all out, and tightened the clutch nuts a bit more, and now it starts much easier.    It's either time for a new oil pump, or a valve on the oil supply line.

[Tigerfeet]

10/30 oil seems very thin for old bikes. I'm not a C11 expert but I'd expect something like straight 40 for a bike of that era.

On the wet sumping - my understanding is that most BSA's will wet sump when parked for a few days. Its related to the gear oil pumps - sooneer or later, with the help of gravity, the oil makes its way through.  (i'm toyng with fitting a new SRM pump to my A50, but note that even this precision pump has 'reduced' bleed past the gears when the bike is standing for long periods...)

And on the question of an oil valve - it seems that everyone who goes that route sooner or later forgets to turn it on. That said - I would have thought a 'remove before flight' red lanyard on the tap would work - you are only going to close the tap when parking the bike back in the garage after use, so the rule would be never close the tap without inserting the lanyard....      You may have guessed that I am also tempted by a tap!  Having to drain the sump before taking my BSA's out is offputting.

[Aquarius]

Would one of these help?
https://www.ebay.co.uk/sch/i.html?_ssn=kingpincomponents&store_cat=27832923016&store_name=Kingpin-Components

[Derek996]

I have on of these anti-wet sump valves on my B32. It works superbly and there is no tap for me to forget to open.
https://www.ebay.co.uk/itm/394925016234?hash=item5bf35d84aa:g:OnwAAOSwOAZZgb6v&amdata=enc%3AAQAIAAAA4GTaW%2FKNnqaLZtYiaUh%2F5rRtg8eWqtMt3kZMBH1pYmbMWODIvpFz%2B1we8G20PFrCq0yeUK%2Bu1hZXAAQOPvaBa7xI9Qhg9dwtMsL5f%2F5zdakgBQv0DYT7tBE0Xf26RmIbo0k9wiL5uwRPcwidevt5uuLcsK3vTD93jFd4DX7qNmjIE1%2BePl8GXioycPGlSNpiGhmHYK%2BSwn9Z2knTmdrb0u1Y89LIXD8Wb4t38ArstAeApkzcPQy0RBIP6asJDNKAOUtP5EjcDRUA%2B79ToySWXcXTSZceXqDJgaIWT2%2BbJK3H%7Ctkp%3ABk9SR7Tzir7mYg