Is your Norton or BSA single or twin dumping all its oil from the tank
into the crankcase when you leave it parked? Make sure you are running thick enough oil
(50 wt Summer, 40 wt Fall and early Spring) and are parking it on compression (pistons at
top of stroke to block off any conrod oilholes).
If the problem persists, you can replace your gear type oilpump with a new one (expensive
and sometimes not easily available), or install one of our Antidrain valves
into the feed line from the tank to the oilpump. Based on a design used by Velocette for
many, many years, these spring loaded valves open as soon as the engine is started. Make
sure your valve is installed in the correct direction and well primed with oil, and your
problem is solved.
A direct replacement version is also available for the stock oiltank screen on
Norton Fastbacks and Pre-Commando models: 06-0592/A.
To
Engine
