"Anti-wet Sump Valve Installation" by Richard Casey

Ok, so you've been thinking about installing a valve to stop the chronic wet sumping of your Norton Big Twin? Well, I thought about that for years and never did it for a few reasons one of them being that I never wanted to take the chance that the valve could fail and cause a fatal lubrication disaster in my engine. Since I just finished restoring an Electric Start Commando and wanted to actually use the starter as the means for starting the bike, that meant curing the wet sump problem for good. Failure to do so would damage the starting mechanism's Sprag clutch which is a $200 item these days. An Internet search for the valve I wanted located the all- aluminum one I wanted at a shop in Australia. Yup, nobody any closer had one on hand. I forked over $59.00 plus $22.00 postal costs via PayPal and a few weeks later it arrived at my door. Funny thing was that it came from RGM Motors in England. I never thought to check with RGM directly or maybe they were out of stock on it at the time.

So, what's the big deal about installing this valve? The main thing is you can't screw up or your engine is toast. What that means is that you can't have any air bubbles in the oil delivery line before or after the valve anywhere between the oil tank and the oil pump gears. What makes it an issue is that you can't see if you have an air pocket (which would cause the pump to cavitate, which means pumping air not oil) or not. I proceeded very carefully and concluded with a properly functioning oil delivery system. Here's what I did and the mistakes I made:

My main mistake was to thing I could do the job by pinching off the oil delivery line with a Vice Grip wrench and simply cutting the oil line and slipping the valve and its hose clamps in place. It didn't work because the valve was too tight a fit onto the oil line which meant I was leaking oil all over my hands preventing my getting a good grip on either the valve or the hose. Also my cuts in the hose were not clean perpendicular so the job wasn't going to look good even if I had been successful. The other flaw in that approach was that I had no way of priming the pump if it had all gone together the first time.

o I thought the process through and finally decided to drain the oil tank into a clean container and then remove the entire oil delivery hose so I could make to perfect incisions in the hose and slide the valve onto the two sections of the oil line hose. That made things mush easier. Before you button up the line you must have is some way of pre-filling the oil line and the anti-wet sump valve before you start the engine. I call this 'priming the pump.' I looked around for some sort of container equipped with a nozzle in which to put a few ounces of oil to prime the pump. I found that a dish soap squeeze bottle happened to have a flip top dispensing nozzle that fit perfectly into the oil line hose. With a few ounces of oil in it I filled the oil line on either side of the valve and then cranked the engine over (with the spark plugs removed) using the electric starter. As the engine cranked I could see the oil being sucked into the line which was a good sign. However it seemed that I cranked and cranked and nothing was returning to the oil take for a while. I thought to myself, "damn, if I had actually started the engine it would be running under load with no oil!" As it turned out, it just took longer to refill the new oil filter I had installed. Finally the oil began spurting out the return pipe inside the oil tank. All was fine in the lubrication system.

I still needed to confirm that this $70 item was doing what it is supposed to do, so I removed the magnetic drain plug and put a catch container under the bike. I let it sit for a week and then checked for evidence of sump valve leakage. I was satisfied to see that very little oil had dribbled into the catch container. The valve was doing its job. I started the bike after reinserting the drain plug and looked in the oil tank and noted that the oil pump was doing its job. Task completed. The E-Start can now be started with the button without needing the ritual drain and refill process before going for a ride. This should assist in extending the life of the fragile Sprag clutch and allowing me and my bad right knee to enjoy many more years of Nortoning.

So here's what you need to remember: Don't try to short cut the sump valve installation procedure. Drain the oil tank and remove the entire delivery line. Install the new valve onto the oil hose pushing the hose all the way onto the valve. Tighten the hose clamps securely. You'll need to shorten the hose by an amount equal to the length of the valve body. The hose is a tight fit and extra hose length doesn't help the process. I positioned my valve aft of the clkutch cable so it doesn't interfere with future cable replacements. Prime the metal oil pipe on the engine and get as much oil into the oil line as you can before you attach it back onto the oil tank. After the job was done I bought a pump type oil can that I would use the next time I installed one of these valves. It will make the job faster and cleaner. The plastic squeeze bottle did the job but it was messy. Be sure to confirm that the entire oiling system is functioning before going for a test ride. The goal is NO AIR BUBBLES in the oil delivery system. I'll probably recheck the oil return function a few more times just to be sure.

Switching topics for a moment, my 1975 E-Start has about 12,000 miles on it and neither the cam nor the layshaft bearing had failed. I changed the layshaft bearing anyway and will keep my eye on the sump screen and magnetic drain plug for any signs of metal flakes from a soft cam. I've put about 600 miles on the bike since Labor Day and so far there's no sign of metallic particulate in the crankcase. The engine has never been apart as far as I know. Looks like not every cam was bad, just those from a certain supplier.

I expect my Norton experience will be more trouble-free than ever and so far the Dyno Dave electric start motor is terrific, the best accessory I ever bought for a Norton.

Rich Casey

Ride ‘em. Don’t hide ‘em!

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Last modified: January 16, 2011.