1966 BMW R69S Restoration: February 1999

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1999 February 1 (Monday)

Speedometer
Speedometer, post repair

Speedometer, post repair

Speedometer, post repair

I picked up my repaired/refurbished speedometer from Palo Alto Speedometer. It looked like this last month. I believe the only difference between how it looks now and how it looked new is the knurled nob used to reset the trip odometer. The original was chromed.

1999 February 4 (Thursday)

Piston cleaning
Cleaning pistons

Cleaning pistons

Cleaning pistons

I couldn’t read the piston size markings through the carbon build-up. The 75mm micrometer I’d ordered hadn’t arrived yet, either. I’m soaking the piston that came from the left cylinder in parts dip to clean it up. This picture shows the carbon on the right piston.

Engine case cleaning
Dirty engine case #1

Dirty engine case #1

Dirty engine case #1
Dirty engine case #2

Dirty engine case #2

Dirty engine case #2
Cleaning, front

Cleaning, front

Cleaning, front
Cleaning, side

Cleaning, side

Cleaning, side
Cleaning, back

Cleaning, back

Cleaning, back

While the pistons are soaking I attacked the engine case. The first two images show the case before I started. I used WD-40 (as a mild solvent), Simple Green, and hot water to remove as much grime and grease as I could. My goal was to get the case dirt and grease free for bead blasting.

1999 February 5 (Friday)

Cleaned piston
Clean piston

Clean piston

Clean piston

This is a close up of the piston after soaking in parts dip for 24 hours. The marking on the left reads 72.92, a 2nd oversize piston. That matched the paperwork that said the cylinders had been bored .040 in 1993. (This is slightly troubling as the second oversize adds 1 mm and and 0.040 inch is 1.016 mm. Might not mean anything.) The other markings on the pistons are Sp 0.08 and what looks like a manufacturer’s logo. For the fun of it I check the old rings: End gap greater than .40 mm (allowable range is 0.25 - 0.40) and ring/groove clearance less than 0.07 mm (allowable range is 0.07 - 0.10 mm).

 

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