Draining the sump

[ray.woolford]

How much oil should I expect when draining the sump of a 650 twin after running it for 1/2 hour then shutting the anti sump valve and leaving overnight.

[Groily]

I'd say about a half pint Ray, based on what I get out typically. I think Neill says '8 fl oz' somewhere in his book on the twins. Obviously he wouldn't be assuming there was a tap in the line - just an engine that didn't wet-sump (much!) probably.
You can see after an oil change and sump drain, when you top up the tank after running for a few mins, how much it takes to get back to where you started. It can be a goodly dollop.
Not all of that difference will flow back to the sump if the anti-drain valve is working to keep some oil in the crank etc for the next start up, but a fair bit will; and there will usually be some sort of pool down below waiting to be scavenged which will sit there when you stop the motor.

[ray.woolford]

Thanks for that , I think I might have a problem as I have just drained just short of 1 1/4 pints from the sump. I suspect there might be a problem with the return pump, as far as I am aware they are the right way round, however the return flow is very airiated so there might be an air leak . Unless anyone else has any ideas.
Thanks Ray

[G15 Roy]

If it's not your bike and you are looking for the problem on someone else's bike has the pump been put back together wrong??.

[Duncan]

Rather ironically I have a tap in line that leaks, a constant fine line of oil is evident when the oil pipe is disconnected from the engine this will run until the tank is empty, may be worth checking the one you have?

[ray.woolford]

No I have checked the tap it's not leaking

[REW]

For what it's worth, when I get home after a run on my 500 twin, I let it idle for at least 30 seconds before stopping the engine. By that time the oil return has turned from a steady flow back to a spluttery trickle, suggesting the sump is now "empty". Next day (or 2 or 3 weeks later) there is little in the sump and I don't have to drain it. If I get back from a run and immediately stop the engine there is significantly more in the sump and the next start takes quite a bit longer to become a splutter rather than a stream again.

HTH