Onan CCK Service Manual

Use a new piston pin to check the pin bushing in the
connecting rod for wear. The clearance should be as
shown in Dimensions and Clearances section.
Before installing new rings on the piston, check the
ring gap by placing each ring squarely in its cylinder
at a position corresponding to the bottom of its travel.
See Figure 71. The gap between the ends of the ring is
given in Dimensions and Clearances section. Rings
which are slightly oversize may be filed as necessary
to obtain the correct gap, but do not use rings which
require too much filing. Standard size rings may be
used on .005-inch oversize pistons. Other oversize
rings must be used with corresponding oversize
pistons. Rings of the tapered type are usually marked
top on one side, or identified in some other manner
ano the ring must be installed with this mark toward
the closed end of the piston.
FIGURE ,71* FITTING PISTON RINGS TO CYLINDER
Space each ring gap one third of the way around the
piston from the preceding one, with no gap directly in
line with the piston pin. The bottom piston ring groove
should be fitted with an expander and an oil control
ring and the two upper grooves fitted with compres¬
sion rings. If a chrome faced ring is used, it will be in
the top groove. The oil control ring is selected for best
performance in regard to the correct unit pressure
characteristics.
The piston is fitted with a full-floating type piston pin.
The pin is kept in place by two lock rings in the piston,
one at each side. Be sure these lock rings are properly
in place before installing the piston and connecting
rod in the engine. Refer to Dimensions and Clearances
section for the correct piston-to-cylinder clearance.
CONNECTING RODS
The connecting rods should be serviced at the same
time the pistons or rods are serviced. Rods must be
removed with the piston. Replaceable bushings and
bearings are used. See Parts Catalog 927-0404 for
available undersize and standard size bearings.
Proper clearance is obtained by replacing the pin
bushing and the bearings. The rod bearings are
precision size and require no reaming.
Install the connecting rods and caps with raised lines
(witness marks) aligned and with the caps facing
toward the oil base. The rod and cap numbered 2 fits
on the crankshaft Journal nearest the bearing plate.
Coat the crankshaft journal bearing surfaces with oil
before installing the rods. Crank the engine by hand
to see that the rods are free. If necessary, rap the
connecting rod cap screws sharply with a soft-faced
hammer to set the rod square on the journal.
Checking Bearing Clearance With' Plastigauge: Make
certain that all parts are marked or identified so that
they are reinstalled in their original positions.
Place a piece of correct size Plastigauge in the
bearing cap the full width of the bearing insert about
1/4 inch (6.35 mm) off center, Figure 72.
Rotate the crank about 30 degrees from bottom dead
center and reinstall the bearing cap. Tighten the bolts
to the torque specified in the Assembly Torques and
Special Tools section. Do not turn the crankshaft
FIGURE 72. MEASURING BEARING CLEARANCE
WITH PLASTIGAUGE

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)