Hitchcocks Forum

Hi just after some options on Classic Engine oil Tank levels , over the years i have heard people say dont fill much over minimum on dipstick but why?

Is it because max oil level is very close to the breather hole connecting the sump to the Oil Tank ?

I never leave the bikes running on side stands so that the oil level will rise towards one side.

I personally run my two enfield at maximum withy no issues .

I was told many years ago that due to wet sumping which occurs when the Bike stands for a few days the oil level in the tank can increase significantly when you start the engine and the surplus oil in the sump is pumped back to the oil tank. When I park my 350 I make sure that the piston is at the top of the stroke so as to avoid wet sumping and I also check the oil level when I come back from a run.I run mine halfway between the minimum and the maximum.

Hi Roy , thanks for reply i also park mine up at tdc whilst layed up to avoid wet sumping but i dont understand why the height of oil in the oil tank should be left at minimum as the bike will wet sump at max or min from the oil tank from timing seal or crankcase half gaskets .

I think the reason is to make allowance for the surplus oil in the sump when it is pumped back to the tank when you start the engine. My Crusader 250cc is a classic for this as the oil level drops to the minimum level if it stands for a week or so but I dare not top it up as when I start the engine the oil level on the dip stick very soon rises to the maximum level. I made the mistake only once by topping it up to the maximum and this resulted in the oil level on the dip stick far exceeding the maximum and it actually overflowed out of the oil cap breather hole.

For my sins I have 7 British Royal Enfields which I acquired and restored over a period of some 40 years the oldest being a 1935 350cc model. I have a 500cc Big Head which is really a nice model and there are not many of them around any more, particularly here in South Africa.Each one has its own strange quirks but they are actually very reliable and usually live up to their slogan of "Made like a Gun."