This bike has the Nikasil plated aluminum cylinders. Nikasil is a nickel silicon carbide material that is extremely hard and wears very little and can be platted onto aluminum. That said, I want to measure the cylinders to determine if they are in good condition since the bike sat for about 25 years and had 64,000 miles on it.
Insert Bore Gauge Into Cylinder & Align With Top Measurement Circle
I previously measured the cylinders on my 1973 R75/5 and you can see that procedure here.
On this bike, I measure the bore, ovality and taper using a bore gauge to see if these cylinders are still serviceable. I found Both cylinders are in good condition.
Bore Gauge Kit
After measuring the cylinders I remove the glaze on the cylinder walls using a ball hone. I use the Brush Research Flex-Hone® with 240 grit aluminum-oxide balls that they recommend for Nikasil cylinders. I use a 3-1/2 inch hone and my portable electric drill that has a low speed range of 600 RPM which is within the recommended 500-800 RPM Brush Research recommends.
Brush Research Flex-Hone Ball Hone & Honing Oil {I Bought WAYYYYY Too Much 🙂 }
After Honing-Good 45 Degree Cross-Hatch
Here is a link to the document showing all the details of how I do this work and a link to a YouTube video.
VIDEO: 1983 BMW R80ST Cylinder Measurements & Honing