Non return valves - anti wet sump valves etc. Confused!!!!

The anti wet sump valve fits in the oil feed line between oil tank and engine. It is strongly recommended that the oil line be full of oil when the valve is put in, and the valve can be primed with oil too. You need a good suction from the oil pump pumping oil for the valve to open, if the pump is pumping air the engine will seize.

had one fitted on my commando for over 10 years no problems at all regards nick

The MkIII timing cover has a non return built in, and that cover can be fitted to earlier engines although it might need a little fettling? My 1973 engine had one fitted when i bought it many years ago but they do have a tendency to stick open, or at least mine does, so that the engine still wet sumps. I don't know of any other internal non return.

To my mind the best answer is a manual valve with a built in elec switch that means you can't start the engine with the tap off, or better yet ride every day so that it doesn't have time to wet sump.

Gentlemen,

Had one fitted to my MkIIA Interstate for ~ 5 years, purchased from Mick Hemmings.

First class, and fixed a wet sump issue permanently, despite a full oil pump "reconstruction!" Also just about to fit one to my 650SS, so would also fit any other model with similar oil tank fittings,

I believe the design is based on a Velocette one. However, as per previous post they have to be "Bled" on installation, but the instructions supplied by Mick are quite clear.

Highly recommended.

Rgds Steve

Fittedthe Mick Hemmings anti-wet sump valve to my MK 3 850and no problem at all so far -high quality ,robust and just followsimple fittingguidelines which includes priming. Thirty five quid odd very well spent.

Found the Norton anti-drain valve in timing cover of the Mk 3to be pretty muchuseless - either it sticksorwhen working doesn't stop oil seeping past when bike left standing for extended periods. Very much a Norton last gasp design on the Mk 3.

a paint of oil in your crankcases its noting to worrie about. but fitting some of the devices can mask the real problem that the oil pump is getting worn. and also with these devices fitted you will not know if and when is worn. the engine will just go bang. the oil pump had stopped working the teeth worn out. so you pay you money and take your choice. fit or not to fit that is the question! Me I leave well alone. and renew the gears in the oil pump.or the pump its self, then you know your getting oil . but the oil pump only feeds the large end bearings and the rocker spindles every thing else is splash feed, this is why its best to leave and pint of oil in the crankcases ,this on start up feeds your main bearings and camshaft. and the back of the bore. and small ends .so any one who drain this off is not doing the engine any favorers, lubrication of a air cooled engine is vital and a oil starved engine is not going to last. also theres the drying out of the main bearing this levies residue on the bearing witch in time build up . and is the main reason for main bearing failure this also the same with the cam shaft and followers residue build up leads to camshaft wear . So all Owners Of Air Cooled Twins and singles Must look after the Oil and keep as clean as possible.

Good points welll made Anna. However, kicking over 745cc of cold engine with a sump full of oil can be a bit of a challenge. Still, mustn't grumble. I must just ride the bike a bit more often. Oddly enough I had a visitor this week borrowing tools who had fitted a tap to the oil feed line on his Atlas. All was well for 4 years and then, inevitably, one day he forgot to switch it on. Which is why he came along to raid my workshop. A cautionary tale.