Forgive me if I'm wrong but it seems to me that all this conjecture is missing one vital point. The oil pump is above the lowest point in the line. The oil lines run under the engine then the galleries to the oil pump run up from there. The natural position of the ASV will be somewhere below the oil pump as a result of oil line routing, meaning the oil, to drain back out of the pump, would have to flow uphill. Unless the laws of gravity are forgiven for oil in a BSA engine, the oil is trapped in a loop between the pump and the ASV, like filling the straw with oil and blocking the bottom end.
Your right Gunk ,I was kind of putting a worst case scenario. With the BSA set up and the imaginary ASV closing the feed line and removing the head of oil there is only a tiny head to push oil out of a leaky pump. Assuming a tight ASV and lines of course. Cheers Pod
71 Devimead A65 750 56 Norbsa 68 Longstroke A65 Cagiva Raptor 650 MZ TS 250 The poster formerly known as Pod
Re: Anti-wet sumping valve....#15729 09/29/0611:42 am09/29/0611:42 am
I have installed at least 100 awsv,s and have had only one problem. When the oil pipe junction was installed an o'ring was displaced while bolting in place. the line was primed, the bike started, oil pressure light went out, all ok, set timing. Next morning I was pleased ther was not one drop of oil under the bike. Restarted, oil light stays on, check oil returning to tank, none, swore, shut off engine. Checked hose clamps, tight, no oil leaks, swore again. ( even good mechanics have bad days). Took off junction and found the displaced o'ring. The slight gap allowed air to be sucked into the feed pipe which caused the loss of prime and prevented the awsv. from opening. Question? why did the o,ring problem not cause an oil leak? Answer. No gravity. Without a awsv oil is pushed through the pump by gravity pushing on the oil in the tank. The anti wet sump valve spring and ball in the line counters this force of gravity, so no oil will leak from the line or FROM THE PUMP. These valves must be fitted with care that no air leaks are present. A lot of my custmers think the valve is the best mod they have done to their bike. I have not had a single engine failure problem on an engine with a valve fitted and do not expect one. I am a little leary of fitting the hidden, inside the oil line valve, and fit the larger model. When a bike has sat for a while, it should not be rushed into service, check all cable opperation, oil level, tire pressure, clutch plates stuck? Whadda think? you driving a car?
This photo shows how the pumps can leak at the join, this is about 40 seconds after wipeing the pump body clean, I would expect oil would spray out there when running. This type of leaking happens before the check valve under the pump, so can wet sump the engine after a few days.
Lannis talks about hanging 2 feet of hose full of oil. The differnce with the bikes is that the oilways are quite narrow and air would be less likely to bubble through the fairly tortuous route back to the valve. I've used a tap on my ES2 for ages - never had a problem (hang the keys on it when it's at home as a reminder to turn it on) - after all, when you do an oil change, do you wait an hour for the oil to prime the pump, or do you kick into life straight away?
When I do an oil change, I put the bike in gear on the centerstand and turn the back wheel until oil is coming out of the return pipe to the oil tank.....
At the VBMC rally a couple years ago, a guy pulled up on a Vincent twin, parked it and snapped a pink elastic lacy garter onto the kickstart pedal. I asked him what that was all about, and he said he always looped the pink garter from his oil tap to his kickstart to remind him to turn it on before he started it.....
We're approaching the tipping point ... where those who vote for a living will outnumber those who work for a living .....
From what I have seen it's not the turn on part that's the problem. It's when you pull up on a distraction and forget to turn it off. Then upon takeing off turn it "on" and really turn it off and ride. I have seen two bikes get blown this way.Riding up on a big group of fine bikes can be distracting.
norbsa 1960 TR6 1963 Super Rocket 1965 650 Star 1966 441 1968 Thunderbolt 1969 Twinkle 250 1972 Fastback 1974 Roadster 1970 S.S Way too many BSA's not named http://decentcycles.com
Originally posted by Mark Parker: This photo shows how the pumps can leak at the join, this is about 40 seconds after wipeing the pump body clean, I would expect oil would spray out there when running. This type of leaking happens before the check valve under the pump, so can wet sump the engine after a few days.
I wonder if that's where my B25's problem is. I've replaced the anti-drain spring and ball, seating it by giving the ball a good tap. It still drains enough over two or three days to reach the level of the gearchange shaft - from where the oil then drips...
I *think* my oil pressure is fine. When cold, the light will go out kicking it over. Also, if the engine stops when cold, it can take a while (read minutes) for the oil light to come on again. Hmm, I guess if the pressure release valve is before the non-return valve, the non-return valve is stopping the pressure dropping but the pressure release could still be leaking from the tank. What sort of oil pressure should be expected when the engine's warm and running?
Check to see if the pump is leaking between the body and case. I have had some issues with unit singles not sealing at this joint. IME, it has been crap gaskets. The ones from Britgaskets seem to work the best.
The oil pressure switch is set to a few psi, a few psi is well below whats needed which is why the light goes off with a kick on a cold engine and doesn't go on until the pressure is released after stopping. As the pressure release is set for 50 or 75 psi depending on the year this is the pressure required with a handful of throttle.