Onan CCK Service Manual

To remove the piston and connecting rod assemblies,
turn the crankshaft until a piston is at the bottom of
the stroke. Remove the nuts from the connecting rod
bolts. Lift the rod bearing cap from the rod and push
the rod and piston assembly out the top of the
cylinder with the handle end of a hammer. Be careful
not to scratch the crankpin or the cylinder wall when
removing these parts.
Keep the connecting rod bearing caps and bearings with their
respective rods.
The pistons are fitted with two compression rings and
one oil control ring with an expander. Remove these
rings from the piston using a piston ring spreader.
Clean the piston ring grooves with a groove cleaner or
the end of a broken ring filed to a sharp point. See
Figure 68. All passages should be cleaned with a non¬
caustic solvent. Clean the rod bore and the back of the
connecting rod bearings thoroughly.
FIGURE 68. CLEANING RING GROOVES
Mark each piston to make sure the rod will be
assembled on the piston from which it was removed.
Remove the piston pin retainer from each side and
push the pin out.
Inspect the pistons for fractures at the ring lands,
skirts and pin bosses. Check for wear at the ring land
using new rings and a feeler gauge as shown in Figure
69.
FIGURE 69. INSPECTING RING LANDS
Improper width ringsorexcessive ring sideclearance
can result in ring breakage. New rings in worn ring
grooves do not have good cylinder wall contact,
Figure 70.
FIGURE 70. NEW RING IN WORN PISTON RING GROOVE
Replace pistons showing signs of bad scoring or
burring, excessive skirt clearance, wavy or worn ring
lands, fractures or damage from detonation. Replace
piston pins showing fractures, scored bores or bores
out of round more than 0.002 inch (0.051 mm).
56

Onan CCK Specifications

General

Cylinders	2
Ignition System	Battery ignition
Fuel Type	Gasoline
Cooling System	Air-cooled
Fuel System	Carburetor
Starter	Electric
Governor	Mechanical
Max RPM	1800 RPM
Engine Type	4-cycle
Bore and Stroke	3.25 x 3.625 inches (82.55 x 92.08 mm)