1973 BMW R75/5: Measuring Cylinders, Pistons and Installing New Rings

I posted a web page on this work where I show how I measured the cylinders and pistons to determine the piston-cylinder clearance, the cylinder taper and cylinder ovality. I honed/deglazed the cylinders and installed new rings grinding the ends to set the gaps to the correct specifications.

The measurements didn’t alarm me so I saw no need to bore out the cylinders and replace the pistons. I did use one over size rings to compensate for the cylinder wear and ground the ends down to the specified ring end gap.

Here are a few of the pictures included in the web page write up.

Zeroing Micrometer with 3 inch Reference

Zeroing Micrometer with 3 inch Reference

Bore Gauge with Dial Indicator

Bore Gauge with Dial Indicator

Setting Bore Gauge to Known Distance

Setting Bore Gauge to Known Distance

Measuring Cylinder Bore Diameter

Measuring Cylinder Bore Diameter

Wear Pattern with Ridge Polished Section of Bore

Wear Pattern Showing Minor Ridge & Polished Section of Bore

Inserting Hone in Cylinder

Inserting Hone in Cylinder

Positioning Ring for Grinding Gap

Positioning Ring for Grinding Gap

Measuring Ring End Gap

Measuring Ring End Gap

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