EARLY OILING
Rob Adams got in touch with a 1924 350cc BSA problem, Perry Barwick had a query about his 1925 model and a call from John Bottomley, baffled while fettling the 1921 Martinsyde at the Brooklands museum, suggested I supply an overview of totalloss oiling, so here goes.
It sounds primitive, squirting oil into the engine to be burned or leaked out, but in truth it’s the same idea as a twostroke, except instead of entering mixed with the fuel, the oil is a dirty, hot puddle splashing around the crankcase.
Fully manual oiling means a hand pump squirt every few miles, regulated by an adjustable needle valve to around four drops a minute viewed through a sight glass. When engine-driven drip-feed pumps arrived, the hand pump remained for an extra squirt on a fast road or to refill the crankcase after draining.
This is the BSAS’ system. Perry’s hand pump didn’t deliver the extra squirt – my fault, I forgot to tell him to open up the regulator screw or it will be restricted to four drops like the auto-pump – a pointer on the dial reminds you of the normal position. Rob’s didn’t work, either, due to a torn washer – but a new one was no better. The cupped washer faces upward so it collapses when you depress the plunger, allowing oil past into the chamber. On its spring-loaded return, it fans out again, forcing the oil now above it into the sight bowl. We decided Rob’s new washer is too thick – it needs to be thin leather to collapse going down or no oil can get by.
John’s Martinsyde problem is overoiling of the V-twin’s rear cylinder. Catching the crankshaft’s oil throw, the rear is always vulnerable to excessive sump oil level. You can only decide an average supply setting by regularly checking the level – but John says the drain plug thread is damaged. Sounds like sorting that is his first job...
Once properly adjusted, total loss works well, but it’s important to understand that you need to know your bike. Different riding – town or open road – may require different settings.