Kawasaki STX-15F service manual Connecting Rod Twist, Connecting Rod Big End Side Clearance

8-22 ENGINE BOTTOM END

Crankshaft and Connecting Rods

Connecting Rod Twist

•On surface plate, set the big-end arbor [A] on V block [C].

•Measure the difference in the heights of the arbor [B] above the surface plate over a 100 mm (3.94 in.) dis- tance-on the arbor to determine the amount of connect- ing rod twist with the connecting rod held horizontally, and

using a height gauge.

If connecting rod twist exceeds the service limit, the con- necting rod must be replaced.

Connecting Rod Twist

Service Limit: 0.2/100 mm (0.008/3.94 in.)

Connecting Rod Big End Side Clearance

•Measure connecting rod big end side clearance [A].
○
Insert a thickness gauge [B] between the big end and ei-
ther crank web to determine clearance.
Connecting Rod Big End Side Clearance
Standard:	0.13 ∼ 0.38 mm (0.0051 ∼ 0.0150 in.)

Service Limit: 0.58 mm (0.023 in.)

If the clearance exceeds the service limit, replace the con- necting rod with a new one and then check clearance again. If clearance is too large after connecting rod re- placement, the crankshaft also must be replaced.

Connecting Rod Big End Bearing Insert/Crankpin Wear

•Measure the bearing insert/crankpin [B] clearance with a plastigage [A].

NOTE

○Tighten the connecting rod big end nuts to the specified torque (see Connecting Rod Installation).

○Do not move the connecting rod and crankshaft during clearance measurement.

Connecting Rod Big End Bearing Insert/Crankpin

Clearance	0.041 ∼ 0.071 mm (0.0016 ∼ 0.00280 in.)
Standard:

Service Limit: 0.11 mm (0.0043 in.)

If clearance is within the standard, no bearing replace- ment is required.

If clearance is between 0.072 mm (0.00284 in.) and the service limit (0.11 mm, 0.0043 in.), replace the bearing inserts [A] with inserts painted blue [B]. Check insert/crankpin clearance with the plastigage. The clear- ance may exceed the standard slightly, but it must not be less than the minimum in order to avoid bearing seizure. If the clearance exceeds the service limit, measure the diameter of the crankpins.

Crankpin Diameter

Standard: 38.984 ∼ 39.000 mm (1.5348 ∼ 1.5354 in.)

Service Limit: 38.97 mm (1.534 in.)