[wessex_man]

Yes all the circulating oil bikes sump from experience. I solder up no 1 hole and use that position as an off during non riding periods. Ive see some add a tap in line but this this looks neater and is simple to reverse if you wish. No real problems with not forgetting to turn it back when in use as the tale tale won't work correctly and we all check it's working when riding don't we.

Oh yes and even though the return scavenges at twice the feed it pays to drain the oil out when heavily sumped so you can turn the flywheels over for easier starting.

I've even had the total loss flat tankers siphon the oil out of the tank, so unscrew the sight gauge to break the seal when not in use. Again you have to remember to re-tighten when in use or else no oil.

Never thought of using any other oil than a straight one for which the engine was designed. Many moons ago I learn't this the hard way with a 350 SV vintage BSA. We were using a multigrade in this and it drank oil even though the bore and rings were good. We cut back the oil to much( to get rid of the smoke) leading to me partially seizing on wet pine needle carpet. How I kept upright is still a mystery today. Anyway we opened the oil regulator up a notch and carried on riding no problems. On inspection luckily not to much damage  re-honed the bore to get rid of the minor scuffs and changed oil which cured the problem Lesson learn't.

[singleminded]

I think that for the telltale to really shut the oil off it would need a seal against the seating..may this problem be worse when multi-grade oils are used? 20/50 is thin when cold whereas straight grade oil is thicker when cold..john

[phutton]

In theory, the tell-tale is supposed to close off the oil supply when it retracts after the engine is stopped. Unfortunately, we all know that theory and practise are not necessarily the same!

P.

[iansoady]

My Model 10 has a permanent wet sump - but then that's how it was designed......

[VicYouel]

Mine all sump too. It is possible to place the three position oil regulator in an artificial off position but oil will still eventually leak down to the sump. Some people even solder up the number 1 position but it does not really help and then you could forget to turn it on again.
Vic

[singleminded]

Yes. Mine will sump all it's oil in less than a week..This is very common with old british bikes. They were designed to be used as everyday transport and if they are used as such 'sumping' will never be a problem. I disconnect and blank off the oil tap if I am not going to use my bike very often..Jphn

[Borada]

I have a 1932 model 9 can anyone tell me if these are prone to wet sumping