2005 Ski-Doo Tundra, Skandic, Expedition Shop Manual, Page 142Get this manual
Section 03 ENGINES (2-STROKE) Subsection 04 (LEAK TEST AND ENGINE DIMENSION MEASUREMENT)
RINGPISTON GROOVE CLEARANCE
Using feeler gauge check clearance between upper compression ring and grooveReplace piston if clearance exceeds specified toleranceRefer to TECHNICAL DATA
Measuring (in crankcase)
First, check deflection with crankshaft in engineIf deflection exceeds the specified tolerance, recheck deflection using V-shaped blocks to determine the defective part(s)See below
Measuring (on bench)
Once engine is disassembled, check crankshaft deflection on V-shaped blocksIf deflection exceeds the specified tolerance, it can be worn bearings or bent crankshaftRemove crankshaft bearings and check deflection again on V-shaped blocks to determine the defective part(s)See measurement in following illustration