Good Thing I Have an Oil Pressure Gauge!

Dan1950

Dan1950

1974 MK II Roadster
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After months of work interspersed with periods of procrastinating, we finally got Trixie fired up. She seemed to want to fight us all the way, but once the key was turned she started on the third kick. The engine sounded sweet, no internal noises and a crisp exhaust note. I kept it above 2000 to assure adequate lubrication to the new Web 312a cam. It was a warm evening so I shut the engine down after about 10 minutes.

The next morning she fired up on the first kick and I again kept the revs up to short cam lubrication. After about 5 minutes though I just had to take it for a ride. Since I live on the edge of town I knew it would not have to do a lot of idling before I got to the open road. She ran sweet power at the lower end was docile, about what it was before but as soon as the rest got up a little you can feel it wanting to run away. Response was impressive but I didn't push the RPMs any. I got on a road that runs along the shore of the St Lawrence River and the bike glided along effortlessly at 55-60 MPH. I gave it a little more throttle and brought the RPM to just under 4000.

I noticed a slight drop in oil pressure, falling to just under 30 PSI.

to be continued
 
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Dan1950 said:
I noticed a slight drop in oil pressure, falling to just under 30 PSI.

to be continued
Click to expand...

About time. :)

Must be a great little ride along the river.

If it is still quiet at idle with 30 psi of oil pressure, I guess that could be normal. Are you concerned about it?

Running under throttle at 4000 RPM it should be between 50 and 60 psi. I am basing those numbers on my 750 though. Could be different for an 850, but I sort of doubt it. My oil pressure gauge is fed off the drive side exhaust rocker spindle cover.
 
Schwany said:
About time. :)

Must be a great little ride along the river.

If it is still quiet at idle with 30 psi of oil pressure, I guess that could be normal. Are you concerned about it?

Running under throttle at 4000 RPM it should be between 50 and 60 psi. I am basing those numbers on my 750 though. Could be different for an 850, but I sort of doubt it. My oil pressure gauge is fed off the drive side exhaust rocker spindle cover.
Click to expand...
There's more to the story. Wait for it.
 
Richard Tool said:
I hope this has a happy ending - too many sad meltdown tales lately…
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No disaster, but it is puzzling and as yet, unresolved. If I hadn't had the oil pressure gauge it would have been a disaster.
 
I found the inlet rocker shafts around the wrong way on my 750 , it made 10 psi difference, now I get 50 psi at about 4000 when hot and if give it a rev up about 58 psi max , idle hot approx 10 to 15 , at the left side of head .This was with 20w/50 high zinc temp most likely around 15 degrees C , my ride was only about 3/4 hour , first ride with gauge , I don't mind it , as I have to glance at the speedo /revcounter as well .
 
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Before everyone tries to diagnose the problem they need to wait on the rest of my observations over the last few days.

In a nutshell, the engine loses oil pressure drastically, less than 10 PSI at speed.
 
Shelby-Right said:
I found the inlet rocker shafts around the wrong way on my 750 , it made 10 psi difference, now I get 50 psi at about 4000 when hot and if give it a rev up about 58 psi max , idle hot approx 10 to 15 , at the left side of head .
Click to expand...
Great info
 
I get 42 hot no matter how fast it goes. But it never falls below 40 at the worst. New pump
fresh rebuild. Blows off at 50 at start up.
 
Dan1950 said:
Before everyone tries to diagnose the problem they need to wait on the rest of my observations over the last few days.

In a nutshell, the engine loses oil pressure drastically, less than 10 PSI at speed.
Click to expand...
Dan, suggest you give the facts you currently have and why you are fretting. Otherwise you're wasting folks' time trying to guess what's going on your end, rather than helping you. 👍
 
Dan1950 said:
Before everyone tries to diagnose the problem they need to wait on the rest of my observations over the last few days.

In a nutshell, the engine loses oil pressure drastically, less than 10 PSI at speed.
Click to expand...
Why don't you post what happened over the last few days rather than playing this drag it out game.
All done here, lots of other threads with actual information to research.
 
He must have read one too many of those trashy Facebook News clips where you must click through 34 pages to learn why some celebrity had their breast implants removed......of course I'm immune to that sort of trash/bait myself:)

Glen
 
Dan1950 said:
There's more to the story. Wait for it.
Click to expand...
I can wait. Sorry it was not a positive first ride. Happens though.

I personally don't care if you drag the story out until you fix it.

Now if'n it were me, I wouldn't have mentioned the first fail until I fixed it. That way I could close the loop before the peanut gallery starts trying to close it for me. 🤣
 
Schwany said:
I can wait. Sorry it was not a positive first ride. Happens though.

I personally don't care if you drag the story out until you fix it.

Now if'n it were me, I wouldn't have mentioned the first fail until I fixed it. That way I could close the loop before the peanut gallery starts trying to close it for me. 🤣
Click to expand...

Ah, the "I know better" oversight committee chimes in.
This commentary coming from a forum participant with over 2,200 posts yet won't put up a cent to support the soapbox on which he stands.
If'n said participant ever considered such while taking shots at those contributing peanut gallery members who do buck up and help support AN.
There is a name for this type of usury activity ..........
 
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Lineslinger said:
Ah, the "I know better" oversight committee chimes in.
This commentary coming from a forum participant with over 2,200 posts yet won't put up a cent to support the soapbox on which he stands.
If'n said participant ever considered such while taking shots at those contributing peanut gallery members who do buck up and help support AN.
There is a name for this type of usury activity ..........
Click to expand...
lol

Guess I hit a nerve.

Getting up in my grill won't accomplish a thing.
 
I apologize for the suspense. I have other things taking up my time so I am not able to post all of my observations.

I will say that once the bikes sits for a while it will start and run with adequate oil pressure for about 10 minutes. There aren't, nor have there been any suspicious noises coming from the engine.

Before the rebuild the engine would run at about 28 PSI oil pressure when warm at cruising speed.
 
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