1966 BMW R69S Restoration: February 2000 [page 4]

The rain stopped for a bit, the sun came out, the temp was above 60 F, and there wasn’t too much wind. Result: painted cylinders and waiting for the paint to dry.

I cleaned up the wiring for the the ground and neutral indicator. While at the back of the transmission I used a bit of pipe cleaner as a safety wire for the clutch lever spring.

Freshly painted cylinder, new gasket, clean piston, new rings, etc. I’m ready to install the cylinders.

I checked the the wrist pin would fit through the connecting rod, then heated the piston a bit to make installation easier. A wooden drift was used to get the wrist pin and snap rings set.

Assembly lube was slobbered all over the cam followers before installation. Once installed the new rubber push-rod tube seals were put into the case.

The replacement rings were slid over the piston with the gaps positioned 120 degrees from each other. Don’t know if they’ll stay that way or not.

The push-rod tubes were set into the cylinders using the appropriate aluminum drift. The tubes were set quite far with the bottom of the tunnel, about 2-3 mm from the head gasket surface.

A very thin layer of Hylomar was applied to both side of the base gasket, ensuring that all oil holes are 100% clean. Then the rings were compressed using the pictured tool.

The cylinder was pushed over the piston. It pushed the ring compression tool back as it slid over the rings. Once all rings were in the cylinder the ring compression tool was removed. The cylinder was then slid almost all the way to the block, leaving just enough space to slide the cylinder nuts between the studs and the cooling fins. Once the nuts were in place the cylinder was seated. A small screwdriver helped get the rubber push-rod seals to seat.

The process was repeated on the right side of the bike. Pictures are the piston with the rings compressed and the installed cylinder.