idle speed vs oil pressure

was cautioned today by a good mechanic to not go below 800 for idle as oil pressure can be compromised. you fellas running an oil pressure gauge; what do you see for pressure at idle?

It probably doesn't matter too much at idle speeds. Stress on the parts are pretty low and it's still pumping oil. I wouldn't let an air cooled bike idle for hours but other than that you should be fine.

rgrigutis wrote;

was cautioned today by a good mechanic to not go below 800 for idle as oil pressure can be compromised. you fellas running an oil pressure gauge; what do you see for pressure at idle?

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Not very much, less than 10psi when very hot, 55psi when cold (at tickover).

I agree with swooshdave, don't let it idle too long. Keep blipping the throttle every now and again, if for example at traffic lights and engine oil is very hot, and let the motorists enjoy the beautiful sounds of a Norton

hi rgrigutis, you,ve got a good mechanic you should be ticking over around 900 to 1000 dont fit a pressure gauge it will just scare you for no reason

I consider the oil pressure gauge one of the better improvements I've made on my Norton. Scared, no. Confident, yes.

I've found a couple of things with the addition of a gauge. One, there is a vast difference in pressure with cold oil vs. hot oil. At startup the pressure is usually at the limit of the pressure relief valve. In my case, that's around 60 psi. When the oil reaches normal operating temperature, the pressure drops to around 10 psi at idle. After you run the bike hard for 20 miles or so, the pressure at idle drops to 2-3 psi. Two, the oil pressure maintains somewhat over 10 psi per 1000 rpm under normal conditions. When the oil pressure drops to zero, regardless of the rpm, STOP! If you don't kill the engine immediately, it will kill itself. With all the plumbing associated with a dry sump engine, I think a gauge or warning light is imperative. The only time I ever lost a Commando engine was when I was running sans gauge. Without a pressure indicator you will discover you've lost oil pressure only after it's too late to save the engine.

Hi Jim,

I once split an oil tank on a '73 750, lost all the oil and seized the engine while doing some enthusiastic riding. I doubt if I would have been looking at an oil guage at the time this happened even if I had one.

I've often considered adding a warning light to compliment the gauge. Most of us would not consider running our cars without some oil pressure indicator, yet think a gauge on a Norton is sacrilegious. Go figure. Let's face it, a lot of the Norton's shortcomings and omissions were strictly due to budgetary constraints. The lack of an oil pressure indicator is one.

JimC said:

I've often considered adding a warning light to compliment the gauge. Most of us would not consider running our cars without some oil pressure indicator, yet think a gauge on a Norton is sacrilegious. Go figure. Let's face it, a lot of the Norton's shortcomings and omissions were strictly due to budgetary constraints. The lack of an oil pressure indicator is one.

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I think the reason is that too many people freak out by the low oil pressure at idle or an incorrectly placed oil feed line. It's easier just to tell most people to not put one on.