[singleminded]

It's not something i like, but these engines are basically the same design as the early total loss oil systems and they relied on very little oil. The roller big ends do not need the same volume of oil that plain white metal bearings that you get in modern engines. For example Vincent !000cc motorcycle engines only have about 3 psi at the bigend feed and do not have a large volume oil pump. Just use good quality oil.

John

[Daniel]

Thank you John. What is your opinion about engine start-up without oil pressure. Is it a problem for the engine to run up to a minute without pressure in idle speed?

[singleminded]

No ,it's fairly normal. These  older bikes were made for daily use so oil leaking past the pump was not a problem. If they are not used for a while they will drain all the oil into the engine and when that's full all over the floor, but I guess you already know that.
So we tend to fit an isolator tap in the pump supply line, in my case I remove the pipe at the tank and fit a blanking cap. The oil in the pipe above the pump will then slowly drain into the crankcase.
When you start the bike again it will take time for the oil to reach the pump gears, I always crack open the fitting closest to the pump(use 2 spanners,one for the nut and the other to hold the fitting into the pump housing) until oil appears then it still takes a little while to pressurise the system. As usual always check for oil return to the tank.
John Hood

[Daniel]

Question about my 1932 M9. When the motor wasn't started for some weeks, it takes a while (up to 30 seconds) to see oil pressure on the gauge and on the tell tale. Is this a problem and if yes, how can I avoid that?

Rgds
Dani