Service Manual

5-18 ENGINE TOP END
Cylinder, Piston
Change to a honing stone for finishing, the final bore diameter should
be as shown in the table.
Be sure the correct stone is used and the stone is not worn.
•
Clean the cylinder at the top and bottom of the cylinder to remove
burns and pieces of the base and head gasket.
•
Anchor the cylinder (block) on the drill press table before honing.
•
Align the center of the cylinder bore to the press center. Set the press
to operate from 200 to 250 rpm.
•
Connect the drive shaft to the hone and set the stop on the drill press
so the hone can only extend 20 to 25 mm (3/4 to 1.0 in.) above the
top or below the bottom of the cylinder liner.
•
Rotate the adjusting nut (knob) on the hone until the stones contact
snugly against the cylinder wall at the narrowest point. “Do not Force”.
•
Turn the stone by hand. If you cannot turn it, the stone is too tight.
Loosen the hone until it can be turned by hand.
•
Be sure that the cylinder and hone are centered and aligned with the
drive shaft and drill spindle.
•
Pour honing oil inside of the cylinder during the honing operation.
Start the drill press. Move the hone up and down in the cylinder
approximately 20 cycles-per-minute.
•
Check the diameter of the cylinder bore regularly during honing, using
an inside micrometer.
CAUTION
Stop the drill press before measuring and remove the hone
from the cylinder.
NOTE

The finish should not be smooth, but have a 40 to 60 degree
crosshatch pattern.
•
Hone the cylinder until it is about 0.007 to 0.009 mm (0.0003 to 0.0004
in) large to allow for shrinkage when the cylinder cools.
NOTE

Do not use gasoline, kerosene, or commercial solvent to clean the
cylinder bore. These fluids only wash all the oil from the cylinder
wall. They do not remove the metal particles produced during
honing.
•
Using soap, warm water and clean rags, clean the cylinder wall. A
clean white rag should not show soil from the cylinder wall.
•
Dry the cylinder and coat with an engine oil.
CAUTION
The cylinder must be thoroughly cleaned after honing to
eliminate all grit.