URAL Motorcycles 2000 -10 series, Repair Manual, Page: 99 / 193

4.4 Cylinders and Pistons
Removing Cylinders
(The engine may be left on the motorcycle with the cylinder heads removed.)
Required tools:
•
crank handle tool 345-316-3 for turning the crankshaft
•
clamping ring tool 345-037 for compressing the piston rings when fitting the cylinder
To remove the cylinder:
1. Set the piston at TDC (top dead center).
2. Turn off the cylinder fastening nuts and carefully ease the cylinder away from the
block by slightly rocking it.
3. If the bottom gasket is damaged, remove it and replace.
Having removed the cylinder, decarbonize it, wash, inspect and measure the cylinder
bore.
Cylinder Inspection and Repair
The required gauge is inside caliper with indicator head with the measuring range of 3.0
to 4.0 inches / 80 to 100 mm and divisions of at least .0005 inch / 0.01 mm.
Before inspecting and measuring, decarbonize the cylinder (top portion) and wash it.
Check for cracks, especially at the neck and mounting flange, also for tight fit of oil
draining tube and the tappet push rod tubes. Visually inspect for scores on the cylinder
bore.
NOTE: If there is visible damage to the cylinder bore, such as deep scores, obvious ring
ridge or warpage, consider replacing the entire cylinder / piston assembly.
If the cylinder appears to be serviceable, measure the bore with the inside caliper at
several different angles and depths. For example, three different depths measured both
in line with the piston pin and at 90 degrees.
Out-of-round and taper are tolerated within 0.002 inch. / 0.05 mm, the cylinder face axis
should be square to the thrust surface of the cylinder flange within 0.002 inch per 4
inches of length (0.06 mm per 100 mm of length). If the cylinder face is out-of-round or
tapered in excess of 0.002 inch / 0.05 mm, or wear exceeds 0.006 inch / 0.15 mm, the
cylinder should be replaced or rebored to the nearest oversize piston (refer to Table 4.4-
1). After reboring, the cylinder face should be honed in a cross-hatch pattern. After
honing, use a brush to wash the cylinder face with a concentrated solution of detergent
in water, then wipe dry and lubricate with light oil. Do not use solvent alone to wash the
cylinder face, as petroleum solvents may not remove fine particles of metal and abrasive
dust off the cylinder walls.