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Old 04-17-2011, 03:19 PM   #56
bmwhacker OP
Still on 3 wheels
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Joined: May 2009
Oddometer: 4,460
One thing usually goes hand in hand with "old school" and that is simplicity. I'm finding that is the case so far with this bike. As bizarre as the engineering is, it is actually very simple so far.

I couldn't take it any more and proceeded to remove the cylinder heads to take a look at the cylinder bores and piston crowns. The engine is "stuck" so I expected the worst.
This is the assortment of tools needed to perform the task of removing the exhaust system, the carbs, the rocker covers and the cylinder heads.:

I have previously given each cylinder a hit of Marvel Oil. Removing the right cylinder head I found a bit of crud sitting in the cylinder. Looked like carbon that the Marvel Oil has loosened up. I carefully removed a light layer of surface rust which had formed on the bottom of the bore. The cylinder was at a compression stroke sequence with both valves closed.

I removed everything I could and wiped the cylinder down. Used some light crocus cloth to get as much of the rust as I could without moving any metal. The cylinders show no ring ridges and the rust has not pitted the right cylinder at all. A one-over bore might take care of everything if all other measurements are within tolerances. Some carbon is trapped around the piston. I wanted the walls as clean as possible so when the piston is freed it doesn't damage anything.

The left cylinder is in a mid-exhaust stroke with the exhaust valve slightly open. The left cylinder was quite clean and shows little or no rust. No ring ridge present.

I reassembled both cylinders and filled them with Marvel Oil. I'll let them soak a couple months while I'm out of state.
I used the same "Marvel Oil" technique on my last BMW engine resurrection. It was in much worse condition as it had sat outside for 15 years. This motor appears to be in much better order so far.

Elapsed time for this entire operation was under 2 hours.
I'm very happy that the bores are in as good of shape as they are. A couple of weeks ago I had peered into the bores through the spark plug holes and it appeared that both cylinders were full of rust.

I'll drain / pull the oil pan next and see what surprises it holds.

Regardless of how far I take this project I WILL hear this engine run.
Total restoration is far beyond my budget but there's nothing wrong with an old beat up runner. Besides if it runs and actually moves under its' own power, it will bring a lot more $$$$ if I decide to sell it off down the line.

There is hope!

Living proof you shouldn't play with matches
ABC# 1992

bmwhacker screwed with this post 04-18-2011 at 10:14 PM
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