Oil pressure reading

Lubrication System (oil feed pump and scavenger pump, reservoir, filter, and lines)
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Pete808
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Oil pressure reading

#1

Post by Pete808 »

Could someone let me know what my oil pressure gauge on my 58 FLH should read at idle? I thought it was around 30psi a week ago but this morning after I rode to work it is around 10psi. Maybe I just looked at it wrong before?
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Re: Oil pressure reading

#2

Post by Bigincher »

Pete, one of the first thing new panhead owners learn is that the oil system works on volume, not pressure.
It's a high-volume low-pressure system by design. The crank bearings are rollers that are constantly flooded, as opposed to an automobile that has crank bushings that are lubricated under pressure.
"Normal" oil pressure on an average panhead motor with 50wt oil will run right around 30psi when cold. However, when the oil heats up and gets thin, the pressure will drop to 3-5 psi. This is totally normal.
You can pull the dipstick cap off the oil tank with the motor running, and should be able to see return oil sputtering back into the tank. This tells you the oiling system is working normally.

An oil pressure guage has no place on a 'volume/flow' system. All it serves is to alarm owners who don't understand how it works. If it freaks you out, take it off and use the pressure switch that it came with.
However- early pressure switches are hard to come by, and later switches and aftermarket switches aren't set to function at low pressure, so they will cause the dash light to come on at idle.
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Re: Oil pressure reading

#3

Post by Buddhahoodvatoloco »

I was goanna say that 8-10lbs is good, I usually read around that, but I have a old funk pressure gauge I use to check. pero El Big Cincher is correcto mundo, pans, knucks do not generate a lot of pressure once they get hot.. I just love the empirical sageness on here.........
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Re: Oil pressure reading

#4

Post by Pete808 »

Thanks for the input. This makes a lot of sense now. The bike runs great after it starts. I am having a little trouble starting the bike. I think it is getting too much gas. I took my spark plugs out and they were black and wet. I messed with the carb adjustment screws just now so hopefully that will fix the issue. I will try to start it again after lunch when I get a few minutes.
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Re: Oil pressure reading

#5

Post by Bigincher »

Pete, check the Panhead Service Manual for initial carb settings and subsequent tuning.
Try two kicks with choke no gas no ignition, then retard spark 2/3, no choke no throttle ignition on.
Avoid choke on and ignition on at the same time. Can backfire and start a fire. I've seen it.
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Re: Oil pressure reading

#6

Post by blewcrab »

Bigincher wrote:Pete, check the Panhead Service Manual for initial carb settings and subsequent tuning.
Try two kicks with choke no gas no ignition, then retard spark 2/3, no choke no throttle ignition on.
Avoid choke on and ignition on at the same time. Can backfire and start a fire. I've seen it.
good advice but if it still dosent start in 1 or 2 kicks .....turn ignition off ,hold throttle full open and kick 3 times .then turn ign. on and kick to start...always start with choke off !
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Re: Oil pressure reading

#7

Post by cdndewey »

When I first got my 62 FL in 1980 it had an oil pressure gauge on it. Same thing..30 plus p.s.i. when first started, damn near zero when warmed up and running. It bugged me for about a year and change until a very good friend (and a smart and excellent mechanic) that owned a 58 told me what Tom said about oil pressure/volume. He never ran one so I removed the one on my 62.

Fast forward a couple of years and I meet up with this fellow with a 62 also. As we were yakking he cracked about his oil pressure and I told him I had the same thing and I fixed mine. He got all excited and was all ears waiting to hear my cure. I think his jaw dropped when I told him I removed and threw away the gauge.
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Re: Oil pressure reading

#8

Post by panhead »

A topic from 2003: Oil pressure question
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