New member with low oil pressure problem

[JJH]

Hi I just joined and would like some advice on a problem I am having with my new (for me) bike.  1979 r65, about 21000 miles, but the last owner only drove it 500 miles in 15 years.  So really just sat around mostly.  I took it out on its first "long" ride, ~15 miles and towards the end the oil pressure light came on at idle.  I fixed that by just keeping the rpm's high at the last couple of stops.  The next time I took it out the light came on when I was actually riding.  I pulled off, turned it off.  Restarted rode awhile, light on, stop, start repeat.  I posted on boxerworks and with their advice I pulled the oil filter and checked for the oil ring/ shim/ gasket.  It was incorrect, so I put in the correct number of shims and started up, but the same behavior happened.  I was given the advice to drop the pan and look at the screen, and/or put a oil pressure gauge to find out what the oil pressure actually is.  I don't have an issue with either of those suggestions, but was wondering if any of you had this issue and what worked.

Thanks,
John

[castledener]

Before you rode the bike you replaced the oil and filters with new..I hope ?

[Bob_Roller]

The first thing you need to do, is to determine if the oil pressure is actually low, or if it is a false indication from the low oil pressure switch .

There is an oil filter bypass valve in the cavity that has the oil filter, it's at the far end, it is a small silver ball that has a spring behind it  .

The oil pressure regulator is in the area of the timing chain at the front of the engine, not so easy to get to .

This most likely is not causing the probelm you have now with the oil pressure light, but it's not uncommon to have the insulation on the oil pressure switch wiring get brittle and break off leaving exposed conductor of the wire .

[JJH]

The oil was, I did not change the filter until the oil pressure light problem.  Previous to the "long" ride, it was just around the neighborhood and parking lots and the light did not come on it those rides.

[Barry]

At least 9 times out 10 low oil pressure is going to be down to filter installation so your problem is unusual.  

I'm not sure how the pick up in the sump could cause low oil pressure. No oil pressure yes but unless it's seriously blocked not low pressure. That leaves the oil pump which is even more work to investigate than dropping the sump. There is a filter bypass valve and a high pressure valve that bleeds off excess pressure to lube the timing chain but I cant see how either could cause the very low oil pressure that would bring on the oil lamp.  So I think the advice to fit a gauge was good as then you'll really know if you have a serious problem or not. The pressure switch is set very very low so for that to come on and it not be faulty indication means there is definitely something wrong.  The pressure gauge will tell you what's happening.  Expect 20-30psi at idle and 70 PSI when you rev it.

[JJH]

Bob, when I pulled the filter to replace it, I saw the little ball valve.  The ball was there and the ball was in the center, but as for it being "correct" I'm not sure I would know what it was supposed to look like.  

To clarify, before I ever rode the bike, I changed the oil but not the filter.  I have now changed the oil and the filter ensuring the correct number of shims are in place

Thanks,

John

[Barry]

John,

The little ball valve you see when changing the filter can have little or no impact on oil pressure as even if it was open all the time it just means the oil bypasses the filter. If anything the pressure would go up a little.

The only reason to inspect that valve by giving it a little prod is to make sure the spring is not broken because bits of broken spring have been know to ruin the bearings. What it should feel like when you prod it with say a chopstick is a very light spring.

[SoloLobo]

Was the white o-ring slightly deformed/squished?

Did you measure the canister depth?  Its not about the number of shims, but about the correct "squish" of the gasket (perhaps that is what you mean)

http://www.largiader.com/tech/filters/canister.html

[Barry]

I think from what I've read, John is very confident that O ring compression is not the problem.

[JJH]

When I removed the filter for replacement there was one shim and o-ring.  The o-ring looked really good and not smashed (which I guess is actually a bad thing).  Anyway prior to replacement I checked the o-ring website(s) and measured the canister depth.  It was deep and calculated the correct number of shims was 3 without a paper gasket.  When I replaced the cover I could feel a slight compression when tightening the screws.  

[Bob_Roller]

Now that my memory got stirred up, I had this happen on my '81 R65 right after I changed the oil and filter .

Bike was still under warranty got the bike back to the dealer, when I went to pick the bike up a week later, I asked what they did .

The response was, they put compressed air in the long tube that the oil filter goes over and ' reset ' the oil pressure regulator, I was skeptical, it seems to have worked .

That was 33 years ago and hasn't happened since .

[montmil]

Be sure the shims went in before the O-ring. Their actual purpose is to prevent the O-ring from being cut by the edge of the filter canister.

With the three shims and a new O-ring, have you taken a test ride to see how the OP lamp is working? No lit lamp would be a good thing.

[JJH]

Montmil-  The shims went in directly after the filter.  They "sat" on the filter canister.

[Barry]

Bob's early experience with his bike sounds an interesting possibility as a cause of low oil pressure. It implies that the relief valve was stuck open even though the set pressure is normally 70 PSI

[JJH]

 I have a question, how long is the center pipe that the filter fits on in a 1979 r65?  Does it extend the entire length of the filter?