What does anyone think of an anti sump valve to cut down on the oil seepage if you let The m20 sit for awhile?

email (option): Jeff@infinitymedspa.com

Well Jeff, half the forum detest them and warn against its use, the other half including myself have installed one and are happy
BUT when you start up the bike, ALWAYS have a look in your oil tank, to see if the bikes lifeblood is bubbling up from the return line

email (option): viaconsu # planet dot nl

As Hans says. They do the job exactly as you would expect. However we've heard the horror stories of when the valve has failed! In my opinion it's not worth the risk. I'd rather fix the problem at it's source or start the bike up more frequently.
An engineer friend of mine who doesn't possess a car licence (yes they are out there), who rides a 1950's Big 4 outfit as daily transport has tried and given up on stopping his engine wet sumping. He has put a straight forward tap in the oil line for when he goes to sea for weeks on end. But he ties a dirty great label to the twist grip as a warning. Ron

email (option): ronpier@talk21.com

I agree with Ron, but on Matchlesses it's quite difficult to fix this, unless a bronze sleeve is pressed in the oil pump cavity in the crankcase, that has to be precision machined first.

Otherwise I would use this sign, found years ago on a fleamarket in CA



Anyone who guesses the year/type/make of the bike wins a free hiking trip to the Vatican.

Cheers,

Lex

email (option): welbike@welbike.net

1943 Flying Flea. But stick your trip to the Vatican.

Ron

email (option): ronpier@talk21.com

email (option): welbike@welbike.net

Ha ha ha! Ooops, Ron!

email (option): snvosselman@hotmail.com

Is it the bike the flea was modelled on? The DKW RT100 of about 1938.. ish

email (option): horror@blueyonder.co.uk

hey, I was going to say that!!!!!

Actually I think it is a Flea, but Ron's just got the year wrong I think. The oil tank's under the frame so I'd say it was a post war bike (from the pictures I've seen) so say 1948

email (option): horror@blueyonder.co.uk

Oh, back to Jeff's question. I've had bikes with valves and taps. The tap scares me as you ARE going to forget one day. So the bike I had with the tap I cable tied ON, this also stops any malicious person turning it off when parked up. I still have an ES2 Norton with a valve and I've had no problems except for if the bike kicks back when starting. The engine is spinning backwards and tries to pump the oil back up the wrong way through the valve and can't. So it spurts oil from the pipe just under the valve. Velocette's have them fitted as standard, and my mate's Velo has never had a problem. I have seen conversions to fit a Velo valve on a Norton Dominator oil tank, and these work as well.

I personally wouldn't go out of my way to fit one. If the bike has wet sumped when you start it, it fills the street with smoke, clears, and away you go. I've never heard of any damage being done from this..?

email (option): horror@blueyonder.co.uk

Yes I should have spotted that a mile away. The tool box (Not oil tank) is under the frame and not under the saddle. Plus rubber foot pegs. So either pre or post war. Is that an Indian 640 behind? Ron

email (option): ronpier@talk21.com

Oh yes, It doesn't have an oil tank being a 2 stroke

email (option): horror@blueyonder.co.uk

I have the anti-wet sump valve fitted on 2 WM20s.

On the first one I fitted the kind that goes directly into to the oil input port,
but it was allot of work (Especially with a right hand sidecar fitted)
So on the second one I installed the kind which goes in the middle
of the feed line hose.

Both work perfectly, but I always peek into oil tank to check circulation.


Noam.

email (option): noam10@gmail.com

I prefer to fix the problem not the symptoms.....If you have a puncture you don't bolt a compressor to the bike to keep up with the air loss.. ...Ian

email (option): ian@wright52.plus.com

i have used instant gasket and a screw to seal a puncture on a tubless tyre to get me home does this count

email (option): roger.beck@node6.com

I think it's a problem that even the British bike manufacturers couldn't solve without a valve. The Triumph Tridents had a ball and spring fitted for this reason and so did the last 850 Commando's. The best thing about this was it was fitted to the pressure side of the oil system, instead of the gravity fed side (hence the small dome on the MKIII Commando timing case) There's no chance of a sticky valve stopping the oil flow when it's coming out the pump at 75psi

email (option): horror@blueyonder.co.uk

The M20 has two anti drain valves as standard..One a 'ball and spring' valve in the timing cover on the pressure side of the pump and one in the base plate of the oil pump. If these are functioning correctly wet sumping isn't a major problem...my M20 and B33 take months to drop a significant amount of oil. There is also the option of replacing, or buying some new parts for, the oilpump which reduces the problem further There really isn't any need to add yet another anti drain valve when BSA thoughtfully provided two...Ian

email (option): ian@wright52.plus.com

I didn't know that Ian, BSA certainly went to town on the problem.

email (option): horror@blueyonder.co.uk

I saw a 30's vtwin bsa once which had a right-hand fuel tap & small rod going down from the lever end to the lever end of another similar tap in the oil line.
It didn't look as untidy as it sounds & was by a long way the most logical fix.
My fix is to drain the oil tanks if not being used, as i put fresh oil in very often.
I was also advised years ago to park bikes with big end at highest point which is going to theoretically give the oil the hardest route to the sump having less gravitational help.

Hi Pj..That set up on the v twin was an original fitment...quite clever I thought...Ian

email (option): ian@wright52.plus.com

Its not on my J12 or any of my friends J12's or Y13's
Which vtwins was it original fittment on ??

Hi PJ..Earlier 770s..My friends had it on and he showed me a tap in his stock of spares with the extra part to attach the rod to..My G14 and Y13 didn't have it either. I must admit I assumed it to be an original part..maybe it was an early example of an 'after market goody'..You will have to refer to 770 parts lists to confirm that, the 770s predate my area of knowledge by quite some margin...Ian

email (option): ian@wright52.plus.com

Im not up on 20's machines either, the one i saw was a J34-11. I looked at another one in Cairo last year (J34-11 military police bike) that had the tap & the solid oil lines were routed in a way a rod could be attached. But i think again the tap had been fitted later. I like to see some of the conversions they did in the past.