Thanks very much for having a look for the stop valve seal Trigger.
That said, since I dismantled and cleaned the pump, and refitted it with 4 new O-rings last week, its stopped draining into the sump! I just went out to the garage, and the level is exactly where it was 4 days ago when I last ran the bike.
maybe that would work for you, OP, or fit Trigger's stop valve seal.
Maybe my stop valve piston wasn't moving freely, or maybe the flat and hard O-rings were leaking, but that seems to be fixed for now, so I'll leave well alone. thanks again for the offer, though.
Interesting that you are getting a leak from the tacho drive, El__burro, I have a slight leak and when I rode the bike I seemed to get a bit of a fog on the glass of the tacho as if it is breathing down the cable. I have a new seal, but with the drive spindle in place, I can only pick at the old seal with my dental pick and damage it more, I couldn't shift it. I'm guessing I may need to go medieval on it and cut it or get a self tapper in there. The downside is that once I start I'll have to see it through, and if unsuccessful the only way to get the drive spindle out is with the cam cover off and the engine out, as far as I can see.
