R80 Oil Pump Case Scoring

I'm in the process of rebuilding my 85' R80 and might have a bit of a problem after pulling the oil pump. There was quite a bit of scoring on the oil pump, which I will replace, but it also resulted in some scoring on the crankcase in the pump recess. It would be great if I could just ignore the scoring but I'm not naive enough to think that I can get away with that.

Can anyone weigh in on how bad the scoring actually is? From my understanding, the two options for fixing this would be to get a new case or get a sleeve insert? What would the cost of the sleeve be? I would feel terrible about replacing a case because of wear on such a small area.

I had one like that and buffed it with a Scotchbrite type pad on a wheel and it looked fine and works fine too. I did put a new oil pump gear in. That is soft metal. I think these bikes have very robust oil pumps, you can measure the gap on your current gears to see if it is in spec.

I’ve recently pondered the same issue/question with an ‘86 R80. Per @bmwrench a sleeve or a new case are the only options but also may not even be necessary. A sleeve would require a complete tear down of the case and you’d have to find somebody that could do that sort of work. You could also reassemble and do an oil pressure test if in doubt if the pump's performance. Here's a link to a how-to if you choose to do a pressure test, including typical pressure values: https://brook.reams.me/bmw-motorcyc...diagnose-intermittent-low-oil-pressure-light/.

I agree that these are very robust oil pumps, although not sure I'd remove any material on the I.D. of the pump housing in order to remove the scoring as you'd effectively be increasing the clearance there with the outer rotor.

I’d also be wondering what caused that scoring. Metal from something was clearly pulled through there. Have you examined the lifters and cam lobes?

I've seen a lot worse that were still working just fine. Usually caused by someone forgetting to change the filter..or remembering about every 20K miles of dirt riding.

I’d be keen to see the main bearings, big ends and crank.

Thanks for feedback! Maybe a new oil pump would be good enough then, although I wonder how big of an effect leaving the scoring would have on the new pump's lifespan?

Cam followers and the cam were all quite pitted so I'm assuming those went with the oil pump. There was a lot more wear on the cam lobes on the flywheel side, haven't thought too much about why that would be yet. The engine is mostly apart, just the crank is left but it looks ok from what I can tell.

The lifter faces break up, which destroys the camshaft. All those sharp hard pieces are pulled through the pump, scoring it and the housing. The oil filter protects the crank bearings.

Magnetic drain plugs begin to look like a good idea.

Always wondered what the leading cause of the lifter failure?

The fact that the airheads are 25 to50 years old may factor into it.

How many miles on it?

Not quite sure but as far as I know 60k+

My 81 rs cam and lifters are nearly 320,000 k’s old, and still look very good with no pitting.
But then I do look after my engine.

I bought this bike as a reason to get my hands dirty, didn't have much history on it and the guy I bought it from said it wasn't running when he started taking it apart. My plan is to get this oil pump situation figured out and then rebuild the rest of it properly. Unfortunately it needs a bit more maintenance than I had hoped but I guess thats how you learn.

Wrench has a theory about poor quality lifters in the mid-80's. He's got records of numerous low-miles mono's with lifter damage. The '86 sitting in my shed has less than 6K on the clock.

The cam followers...



And the resultant oil pump scoring...



The cam had no discernible damage but I replaced it anyhow along with the lifters. Also replaced the oil pump components and all of the tolerances are well within spec and the pump is working great.

I dealt with the exact same thing maybe 5 or 6 years ago. Front bearing pin dropped out, bearing shifted, cam and follower destroyed each other, oil pump got trashed. '85 R80. I replaced the case.

I just heard of another one the other day.

Yes Virginia, lifters sometimes DO break-up.



Notice the crack on the bottom one, it's about to come apart. These were from a motor with about 50K miles. These were from a motor from 1972.

That's why they changed to vertical lifter slots instead of the angled ones.

Maybe I should put those trashed lifters on Ebay, like those idiots trying to sell used oil filters!

Had a chance to pull the crank and get some pictures today. Main bearing carrier slid out easily which was nice and has luckily been the theme for most of the tear down.

Crank seems to look ok to me but I'm not a trained eye yet. Also added some pictures of the oil pump and cam.