Onan NHC Series Operator's/Service Manual And Parts Catalog page 90

Piston Ring Gap in Cylinder ' • • 0.010 0.020
Piston Ring Side-Clearance (Top compression ring only) . 0.006
Breaker Point Gap (Full Separation) 0.020
Spark Plug Gap - For Gasoline Fuel 0.025
Crankshaft Main Bearing Journal - Standard Size . .. 1.9992 2.0000
Main Bearing Diameter . . . . . . • • • 2.0015 2.0040
Main Bearing Clearance • • 0.0015 0.0043 .
Crankshaft Rod Bearing Journal - Standard Size 1.6252 1.6260
Cylinder Bore - Standard Size . . . ' 3.5625 3.5635
* Set exhaust valve at .014 for gaseous fuel operation.