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patsta
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1957 R60. Troubleshooting oil leak through right side exhaust while engine is running. Good compression (~9 bars) on both cylinders, and good leakdown readings. Some leakage is audible out the dipstick hole during leakdown test, but the % leakdown reading is good (at least according to the chinese meter scale).

However, while running the engine I tried to pull the dipstick. And I think it is safe to say that the crank pressure during running of the engine is quite excessive. If threaded out, the dipstick is "dancing violently" in the dipstick hole.

I understand that the principle of breathing on these machines are somewhat special, with a rotating breather plate attached to the camshaft. Is this correct? Can something in this setup have been assembled the wrong way by the previous owner?

patsta
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Video of "the situation" for

Video of "the situation" for your amusement: https://youtu.be/4BIIAq0SRzM

Poor filming as I was one hand short while filming, operating the throttle, and pulling the dipstick at the same time.

schrader7032
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VBMWMO #7032
San Antonio, TX
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I would never have thought to

I would never have thought to do that test...kind of got things messy! Seems to me that with the pistons coming down to bottom dead center, that's going to push a lot of air...which would result in a lot of air coming out of the dipstick hole.

What was the leakdown percent? How many miles ago was the engine rebuild done? Do you know who did the work?

You say leaking out the right side exhaust...where is that? Are you saying that oil is coming out through the exhaust port and onto the header pipe? Or are you saying it's coming out the muffler?

With everything back together, engine started, are you feeling any air coming out of the small breather tube that comes out of the crankcase just forward of the left cylinder? It's a small curved pipe. If there's no air coming out there, then things might be assembled 180 out.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

malmac
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Toowoomba, Australia
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some background about breather plate

A short while back I rebuilt my son's R60/2. In the process I replaced his failed early pin breather with a new breather with cast in locating device.

Here are a couple of pics I took during the process.
What I had to do was work out how to modify the old timing gear so the new breather plate would work correctly.
This required that a extra set of holes were machined into the timing gear in the correct location.

Unfortunately it is possible to just put the new breather cast in locating devices into the holes used for removing the screws which hold the bearing carrier which sits behind the timing gear on the cam shaft.
To do so would certainly mean the breather would not perform as designed.

Your bike may not have this problem - however this information may be useful in ruling out that possibility.
Note the breather plate is significantly out of time if the wrong holes are used - however the new cast in locating devices are not in the same place on the plate relative to the holes in the breather plate - from memory I think there might have been a small amount of overlap, so the breather plate might work very very poorly.

Mal

  • Machining a carrier to hold the timing gear
  • I stamped in letters to aid in assembly
  • Timing gear being assembled to engine
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mal - R69s
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312Icarus
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I think (at least in my case)

I think (at least in my case) the dipstick “dancing around” is quite normal. Feel in front of the crank case breather and see if it is “pufffing”?

Icarus

patsta
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Norway
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Thank you guys for great

Thank you guys for great info. I will check the operation of the breather pipe. Maybe this is actually normal operation.
The oil leak is coming out the muffler. What are probable causes? I would say the leak is significant. Oil is almost "sputtering" out the muffler end.
No info on when the machine has been rebuilt.
Leakdown less than 10 %

schrader7032
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VBMWMO #7032
San Antonio, TX
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For oil to be coming out the

For oil to be coming out the muffler, it's coming through the exhaust valve or maybe more likely the exhaust valve guide. I presume you've going through the process of setting valve clearances. But I might suspect the valve guide.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

malmac
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Toowoomba, Australia
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Crankcase oil level

I know it sounds almost insulting, however have you checked your oil level. I have seem people check the level by screwing in the dip stick and then making sure the oil is up to the full mark when measured that way. It results in the crankcase being significantly over filled.

No offence intended.

Also BMW's were renowned for rusting out mufflers - back in the 70's we would put sump oil into the muffler to prevent rust. I would take the muffler off and see how much oil is in the muffler and also the condition of the header pipe where it enters the muffler. Again just looking for explanations that are simple.

Mal

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mal - R69s
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patsta
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Norway
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Oil level

Wouldn't measuring with the dip stick screwed in result in underfilling of the oil level?
However yes, the oil level is correct.

And I guess the exhaust valve guide is a quite possible suspect, wouldn't this also explain the good leakdown values, as the leak would only occur while the valve is open, during the up-stroke of the piston?

However, some bad news: I read in another post someone suggesting to operate the clutch while observing for movement on the flywheel, to check for defect main bearings. I performed this test, and I can actually see the flywheel shifting. The movement is ever so slight, max a couple of tenths of a millimeter. Hovever, am I correct to think this is a quite bad sign? Am I in for a full overhaul?

312Icarus
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Oil in the muffler suggests

Oil in the muffler suggests tired rings, bad valve guides. As has been suggested, remove the mufffler and dry it out. And then see.

Icarus

Jim D 5112
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Oil out the muffler

Is this something that just started or are you a new owner? If the oil level is full and seems to be staying up. I would just run it and watch the oil level. The PO may have put oil in the muffler to help control rust. And yes the motor will blow lot of oil out and make the dipstick jump around. Any plug to the crankcase that is removed on a running motor will do that. Just think of the motor as a big air pump on the bottom end. And yes check that the breather is working.

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