Walneck's Classic Cycle Trader - November 2008 - (Page 28)

MONTHLY FEATURES TIP OF THE MONTH ? Do As I Say Not As I Do Department Musings on an Anti-Wet Sump Valve By Mike Brown I swore I’d never do this, but circumstances change, as do attitudes. Still, as far as I’m concerned, the jury is still out on this particular fix, the installation of an anti-wet sump valve. Personally, I’d wait until at least a year goes by and you haven’t read the piece on “How to Blow Up Your Engine in One Easy Step.” OK, with the lawyers placated and all the advertisers selling these valves madder than Jesse Jackson at a KKK rally, let’s take a look at wet sumping in general and do a quick review of the options at hand. The intention here is to educate, not advocate, and I can’t make it any clearer than that. Wet sumping, for those of you who don’t own BSAs or Nortons, is a situation whereby the supposedly dry sump system of the motorcycle begins to fill with more oil than Jed Clampit discovered. Other bikes can suffer from wet sumping as well, but the two makes just mentioned are infamous for it. The BSA in this case shouldn’t have had much more than about 100 ccs in the sump at any time, but if left long enough, it filled to way over a quart, sometimes so much that it leaked all over, probably from the camshaft breather passage, which is pretty high up in the case. Even when it didn’t leak, it smoked like the dickens when it started after sitting for a couple of weeks and caused excessive crankcase pressure that can blow oil seals and gaskets. It’s very easy to tell if you have this problem by consulting a good shop manual and finding out how much oil is allowed in the sump, and then draining and measuring what you removed. I’ve generally found more in most old bikes than what was called for, but extremely excessive amounts clearly indicate a wet sumping issue. The EPA showing up every time you start the bike is a dead giveaway too. Wet sumping can be caused by various, often easily correctable faults, so it’s a good idea to rule these out. Common problems include a faulty by-pass valve, loose or obstructed pickup tube and loose or very worn oil pump itself. Another common cause is a restriction in the return line to the oil tank or a plugged tank vent causing backpressure. However, in 99 times out of a hundred, with BSA A50/65s the problem is really in initial design. The BSA has its own anti-wet sumping valve built in, a small check ball held against the pump by a tiny spring. It takes very little wear, or just a minute particle between the check ball and pump to create problems. The cool thing is that, in most cases, the leak into the sump is very slow, so if you ride the bike regularly, you probably won’t even know it wet sumps. However, besides from getting fatter and lazier every year, I’ve also managed to accumulate so many bikes that riding the BSA often doesn’t If you do plan to install an anti-wet sump valve, wise insurance is to also install a means to check oil pressure and/or test the existing system. Already we have too much oil in the sump and it’s still draining. This is what came out of the BSA’s sump. The common culprits for wet-sumping are shown. Improvement can be had for fitting a new spring and check ball. Make sure the ball fits perfectly in the pump’s recess. If it does not, a little valve compound can be used to dress off the seat, but be very careful to remove all compound before installing the pump. On installation, check to see the gasket is a good fit and does not obstruct the check ball, another common problem that’s easy to fix. Also be sure to use new lock nuts and washers when reinstalling the pump. Loose pumps are also common causes for wet-sumping. Lots of times, though, the problem still persists. 28 November 2008 | WALNECK’S CLASSIC CYCLE TRADER® I WALNECKS.COM

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Walneck's Classic Cycle Trader - November 2008 Contents American The Buzz w/Buzz Walneck Our Winners Stories! By Rick Weiler 1962 Henkel Tourist Motorcycle Tips w/Mike Brown Our Winners Stories! By Tom Sutherland Event Listings & Advertisements Bench Racing w/Mark Zimmerman British Biker of the Month: Hagon Shocks European Japanese Davenport Show Recap Motorbikes & Scooters 1956 Maico Mobil 197cc 1952 45cc VeloSolex Memorbilia Antique Cycle Clubs Parts, Accessories, Want Ads How to Place a Word Ad How To Place a Photo Ad Area Code Directory How To Subscribe Let Us Help With Your Event

Walneck's Classic Cycle Trader - November 2008

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