If your bike wet sumps, run a length of pipe from the crankcase breather to the rear sprocket.
Hey presto, you have a Scottoiler!
email (option): sacombsashtrees@hotmail.com
I've got one on my 16H, works really well. Without it the crank cases were filling up and flooding out through the hole at the bottom of the drive side case bearing boss. I've lapped the pump and it still does it. The valve screws into the crankcase so it's as near the pump as it can be. The 16H has an oil indicator so I can see it's working. I also have one on my ES2 and never had a problem. If you are worried, look inside the oil tank to make sure it's returning, once it is, it's not going to get stuck. Velocette fitted them as standard and I've never heard of a problem with them. I hate oil taps, you ARE going to forget about it one day. My twin cylinder bikes wet sump and I just kick it over a few times, start it and smoke out the street 
You have to look hard to see it.
email (option): horror@blueyonder.co.uk
All my three BSAs are fitted with them with no problems. My Velocette is fitted with one as standard.
Your right Horror, I have on fitted to my 16H also. Its been fitted since 2001 and not a bit of a problem and this bike gets ridden fairly hard. The one fitted to my M33 screws direct into the crankcase also and is made for the singles BSA range, that's been in it for a few years and saves a lot of bother draining crankcases and overfilled clutch cases. The M33 that it's fitted too takes the winter to sump so i think there is not much wrong with the pump and the original valves apart from a little bit of wear. If you are bothered about 2 many valves in the system on a BSA you could take out the leaking ball and spring in the timing cover as its no use if you have the new external one fitted, the ball at the bottom of the pump has not a spring behind it so suction should not be a problem.
I have just got back from a 3 day rally in the Lakes taking in most of the high passes, Went on the girder M33 near 500 miles and it ran ace and it had pleny of stick. 3 days of good weather and a ride home through the Dales today using as many back roads as you can.
These bikes are meant to be ridden and if you used them once a week they would not sump unless there is something really worn in the pump.
At £37 for a valve i think they are good value for money and am sure there is not a restriction in the oil flow with this type of valve.
Tim W
email (option): t.j.walker@btinternet.com
Hi horror
Can you tell me where you got your wet sump valve, it looks neater than the one on eBay with 2 jubilee clips thanks
email (option): richard_radley@hotmail.com
It's fair to say many people run these valves without problems, though I personally know of two engine failures that were directly attributable to the fitment of such a valve....That may, or may not, confirm my theory (fear) that you can't have a 'one size fits all' valve that will work on any engine and with any oil pump...
I recently experienced a lot of wet sumping problems when I fitted another engine into my B33 and I admit it tested my patience to the limit to get to the bottom of the problem and to find a cure without fitting an anti drain valve...
After all, I reasoned the B33 (and M20) already have two of those within the original design specification...I did actually buy an anti drain valve but couldn't bring myself to fit it!!:laughing: ...
Treating the symptom (wet sumping) rather than the problem (the cause of the wet sumping) goes rather against the grain of my engineering training and experience....
To summarise the situation in one phrase, it's was all about wear in the oil pump and the consequent excessive clearances...
Fortunately I have a number of used pumps and two NOS ones (which I was saving for other projects) so I was able to selectively build up a very good pump that is dimensionally close to the original NOS one and I've had no further problems since fitting it...It took a lot of time though!....Ian
email (option): ian@wright52.plus.com
I have fitted valves to my brothers and my sons Matchless G3ls from this company.
http://www.kingpincomponents.co.uk/oil-tap-with-cutout-switch I have no connection to the company,I saw them on their stall at Kempton Park jumble. The valve and switch work well,I see no reason for this to be a problem. I just make sure I ride my Matchless often enough that it doesnt wet sump in the first place ! But my AJS trials bike has a tap as it is not used so much now,I use a "Remove before flight tag" on the petrol tap to remind me,thats been working as a system for the last 10 years.
I had one fail on my bike, luckily enough I had an oil pressure gauge. A dealer I know also removes them from the bikes he sells as he has also had one fail on him.
Can you tell me where you got your wet sump valve, it looks neater than the one on eBay with 2 jubilee clips thanks
It comes with nuts etc to fit in line, but I screw it into the crank case and the oil pipe union straight to it. Make sure it's the right thread for your bike if you're going to fit it this way.
I think if it's a good quality one there's no problem. Coincidentally my mate came round on his Velo 500cc and looking at the valve which is standard on his bike, it's fitted on the oil tank, so quite a way from the pump. The pipe needs to be primed as the pump can't pump air, so I would think a long pipe would risk getting air in it, but my mate has never had a problem with his bike. The other thing is people fit the wrong type of valve with a rubber washer/flap which are used for breather or fuel valves which force past under pressure. I think the rubber flap can stick.
I've fitted one to my Model 18 the same as my 16H and again it's excellent.
email (option): horror@blueyonder.co.uk
I think I'm right in saying that Velo claim to have invented it. I also think that they were fitted as standard to the oil tanks from early post war....and of course, retro fitted to earlier models. The wet sumping on Velos is obviously a trait and both my WD models have them, as it doesn't take long for the oil to leak through the main bearings and over fill the primary case all over the floor. Ron:rage:
email (option): ronpier@talk21.com
I have two Velocette's and both have the anti sumping valve. They work great and have never had any issues. As for BSA's having a sumping issue, my M21 most definitely does. In my experience it depends where you live and how hot it gets in the summer. If it is 100 degrees F for a number of days in the summer it will sump regardless of how perfect the oil pump is. In the cold winter, no sumping problems. My Norton Commando, AJS, Matchless and even Triumphs with a plunger pump will sump in the summer.
Yes, I know if I rode the bikes more often it would not happen but I have 26 bikes and can't ride them all the time.
[ If it is 100 degrees F ]...
I didn't know it went up that high...:laughing: ...Ian
email (option): ian@wright52.plus.com
Yes, I know if I rode the bikes more often it would not happen but I have 26 bikes and can't ride them all the time.
I only have two. That makes me some kind of freak in the world of old motorcycles.
Rik maybe you are lucky as you have 24 less headaches than Jonathon.
email (option): tknalder@iinet.net.au
I have such a valve in my Norton Commando for years now. No problems, although I was scared at first.
Its a very small one, from the US somewhere. Made of plastic, you can see the oil pass.
My M20 never needed one (!)and I have it since 1974
The valve BSA fitted is a ball bearing on the end of a spring.
The add on valve is either a ball or a piston depending upon which one you buy,
They work exactly the same way as the one BSA fitted.
They have the same problem as the one BSA originally fitted.
Every second the engine s running hot oil flows around a ball , through a spring, then into the engine.
This heats up the spring which causes the spring to go soft over time so it does not push the ball hard enough to shut off the oil flow.
Then there is the next problem that the oil flowing around the ball, through the hole in the cases erodes the case, just the same as water flowing over a rock erodes a groove in the rock.
Thus from time to time the hole needs to be dressed and the spring needs to be replaced.
Back when my A10 & B40 were my daily transport, the spring was considered a service item and replaced regularly.
The real problem is BSA did not publish a free length for the spring.
If it did we would take it out & measure it.
Because they did not then clowns pull it out, squeeze it between their fingers say "yep shees right then shove it back in.
MY bike does not wet sump any more.
When I got it the entire oil tank would drain out almost overnight.
Now there is barely a drop in 6 months which is the longest the bike has sat idle for the last 25 years.
I find great mirth in the fact that the same people who are empathic about the need to prime the oil pump on a rebuilt engine and carry on about how a gear pump can not "suck air" ( which is quite correct ) then go out & fit an external valve so the pump can drain all of the oil below the valve through the pump & into the sump then expect the pump to "suck air" hard enough to pull the ball off the seat on the external valve
email (option): bsansw1@tpg.com.au
The spec for the valve given in the M20 standards book is Ball 1/4", Spring 21 coils, I.W.G. 28 (0.0148") free length 7/8".
For the sake of about a fiver inc post! It's just as easy to fit a new ball and spring. First give the ball a sharp tap with a small hammer and skinny drift to improve its seat. Ron
email (option): ronpier@talk21.com
[They work exactly the same way as the one BSA fitted..]
Not exactly...The BSA system relies on pumping pressure against the 'blind' gallery created by the ball on its seat which is located 'downstream' from the pump...Under these conditions the BSA pump can easily lift the ball off its seat, which it does at approx. 7PSI...In fact it's more or less impossible that it won't do so as it is a hydraulic operation with very unequal pumping and seating pressures....
With the aftermarket valves the ball has to be sucked of its seat by a vacuum produced by the pump and the effectiveness of this method is far more subject to variables such as pump wear and it is questionable that the pump was even intended to have this capability...
Short of getting the original system to function as intended, which I feel is the ideal way to go, then the next most effective and reliable method would be to fit a plain on/off tap with an electrical cut off incorporated to ensure it has to be opened before the engine is run...These are currently available as detailed in a previous post and work well...
The aftermarket anti drain valves, over which there is a justifiable question, backed up by anecdotal evidence, as to whether they are actually suitable for all engines and conditions cannot therefore be argued to be the best choice IMO but only an available choice, which it's fair to say, does carry an element of risk as well as benefit...Ian
email (option): ian@wright52.plus.com
Its a very small one, from the US somewhere. Made of plastic, you can see the oil pass.
My M20 never needed one (!)and I have it since 1974
email (option): horror@blueyonder.co.uk
The add on valve is either a ball or a piston depending upon which one you buy,
They work exactly the same way as the one BSA fitted.
They have the same problem as the one BSA originally fitted.
Every second the engine s running hot oil flows around a ball , through a spring, then into the engine.
This heats up the spring which causes the spring to go soft over time so it does not push the ball hard enough to shut off the oil flow.
Then there is the next problem that the oil flowing around the ball, through the hole in the cases erodes the case, just the same as water flowing over a rock erodes a groove in the rock.
Thus from time to time the hole needs to be dressed and the spring needs to be replaced.
Back when my A10 & B40 were my daily transport, the spring was considered a service item and replaced regularly.
The real problem is BSA did not publish a free length for the spring.
If it did we would take it out & measure it.
Because they did not then clowns pull it out, squeeze it between their fingers say "yep shees right then shove it back in.
MY bike does not wet sump any more.
When I got it the entire oil tank would drain out almost overnight.
Now there is barely a drop in 6 months which is the longest the bike has sat idle for the last 25 years.
I find great mirth in the fact that the same people who are empathic about the need to prime the oil pump on a rebuilt engine and carry on about how a gear pump can not "suck air" ( which is quite correct ) then go out & fit an external valve so the pump can drain all of the oil below the valve through the pump & into the sump then expect the pump to "suck air" hard enough to pull the ball off the seat on the external valve
I'm not telling people to fit a valve, that's up to you. It solved a problem I couldn't fix, as it was so bad that oil was covering the floor in days and it was the only answer on a Norton. I had the same fears from reading posts on forums and I can only say my experiences of using them.
email (option): horror@blueyonder.co.uk
Not exactly...The BSA system relies on pumping pressure against the 'blind' gallery created by the ball on its seat which is located 'downstream' from the pump...Under these conditions the BSA pump can easily lift the ball off its seat, which it does at approx. 7PSI...In fact it's more or less impossible that it won't do so as it is a hydraulic operation with very unequal pumping and seating pressures....
With the aftermarket valves the ball has to be sucked of its seat by a vacuum produced by the pump and the effectiveness of this method is far more subject to variables such as pump wear and it is questionable that the pump was even intended to have this capability...
Short of getting the original system to function as intended, which I feel is the ideal way to go, then the next most effective and reliable method would be to fit a plain on/off tap with an electrical cut off incorporated to ensure it has to be opened before the engine is run...These are currently available as detailed in a previous post and work well...
The aftermarket anti drain valves, over which there is a justifiable question, backed up by anecdotal evidence, as to whether they are actually suitable for all engines and conditions cannot therefore be argued to be the best choice IMO but only an available choice, which it's fair to say, does carry an element of risk as well as benefit...Ian
I will take that one on the chin.
The other thing to remember is BSA use a gear pump where as most other makers used a piston pump.
Piston pumps have a much easier time creating a low pressure ( sucking ).
As such a lot of bike with piston pumps never fitted a valve because in theory it is not needed.
Gear pumps are good at creating pressure, but poor at creating suction as there are a mile of places to leak.
If fitting a new ball & spring after seating properly ( I use the old ball ) the bike still wet sumps then you have a problem with your lubrication system.
The pump has badly worn side plates, the gears are badly worn, the pump is not seated properly, etc etc etc.
It is better fixed now than finding about it crossing an expressway with 60 tons of truck up your clacker.
email (option): bsansw1@tpg.com.au
Excellent .
Never seen that spec before thanks for sharing.
I might just go down the workshop & test the rest of the box I bought decades ago.
email (option): bsansw1@tpg.com.au