Piston: Testing and Inspection

1. Inspect outer circumferences of all pistons for seizure or scoring, replacing as necessary.
2. Measure outer diameter of each piston at 90° (right) angle to piston pin, 0.87 inch (22 mm) below oil ring land lower edge, and note the following:
a. On 1993 models, piston diameter should be 3.5411 - 3.5419 inches (89.944 - 89.964 mm).
b. On 1994-95 models, piston diameter should be 3.5417 - 3.5429 inches (89.958 - 89.990 mm).
c. Pistons are available in 0.01 and 0.02 inch (0.25 and 0.50 mm) oversize.
3. Check piston to cylinder clearance. Results should be as follows:
a. On 1993 models, measurement should be between 0.0009 - 0.002 inch. If clearance exceeds 0.0059 inch (0.15 mm), replace piston or rebore cylinders to fit oversize pistons. Whenever replacing pistons, use new piston rings.
b. On 1994-95 models, measurement should be between 0.0009 - 0.0020 inch. If clearance exceeds 0.0056 inch (0.14 mm), replace piston or rebore cylinders to fit oversize pistons. Whenever replacing pistons, use new piston rings.

4. Measure piston ring to ring land clearance around circumference with new piston ring. Clearance should be 0.0012 - 0.0027 inch (0.030 - 0.06 mm). If clearance exceeds 0.006 inch (0.15 mm), replace piston.
5. Inspect piston rings for damage, abnormal wear or breakage, replacing as necessary.
6. Insert piston ring into cylinder by hand and use piston to push it to bottom of ring travel.
7. Measure each piston ring end gap. If end gap exceeds 0.039 inch (1 mm), replace ring(s).
8. Measure piston pin hole diameter. Diameter should be as follows:
a. On 1993-94 models, diameter should be 0.9048 - 0.9057 inch (22.982 - 23.006 mm).
b. On 1995 models, diameter should be 0.9051 - 0.9055 inch (22.988 - 23.000 mm).

9. Measure piston pin diameter. Diameter should be 0.9045 - 0.9047 inch (22.974-22.980 mm).
10. Check piston pin to piston clearance. If clearance is not 0.0004 - 0.0010 inch (0.008 - 0.026 mm), replace piston and/or pin.