1966 BMW R69S Restoration: January 1999 [page 2]
1999 January 20 (Wednesday)
It is time to start opening this thing up. I went through the paperwork that came with the bike and see that the cylinders were bored to 2nd over size and an “unleaded” conversion was done to the heads. This occurred in Feb ‘93. Don’t know how many miles ago that was, but I don’t suspect too many.
Cylinder head removal
The garage was a mess. After moving the frame out of the way I sat the engine on a short stand/table so I could sit on a little work stool and work in relative comfort. The third picture shows me ready to pull the cylinder heads.
I removed the valve cover for the left cylinder and noted that new valve covers gaskets are needed. The four bolt holding the rocker arm assemblies were removed followed by the the lower head bolt and the upper head bolt. The head came off easily. The head gasket looks new. I’ll keep them as spares.
Pictures of the left cylinder and the cylinder head components.
I rotated the engine 180 degrees to pull the right cylinder head. This is the cylinder that was noisy. One interesting thing is that my 1/2 drive 14 mm socket wouldn’t fit through the opening in the fins to access the lower cylinder screw. The same socket fit on the left cylinder head. I used a 3/8 drive 14 mm socket on this side as it had a smaller outside diameter.
Rocker arm assembly
When I pulled the exhaust rocker arm assembly from the right cylinder head it practically fell apart in my hand. The first picture shows two of the needle bearings that fell out. I pulled the unit completely apart to ensure I had all 34 needles. When I put it back together I used cable ties hold the assembly together for storage. I need to find out what the proper fix is. I suspect that this was at least part of the reason why the right cylinder was so noisy.
Now that the cylinder heads are off pull the cylinders and remove the pistons.
I removed the right cylinder and put a bit of stiff cardboard around the connecting rod so it doesn’t bounce on the case. Marks on the case tell me that previous disassemblers weren’t so careful.
I removed the snap-ring from one side of the piston and pushed the wrist-pin out with wooden drift whittled from an old broomstick handle. Heat was not needed for this side.
Left cylinder and piston
The left cylinder came off as easy as the right. The wrist-pin, however, was harder. I removed a snap-ring and found that the wrist-pin would move in the piston (without heat) but seemed stuck to the connecting rod. I removed the other snap-ring. The wrist-pin didn’t want to go in that direction, either. Finally some heat aimed at the little end of the connecting rod and some gentle taps with my wooden drift got the wrist-pin to move.