Engine Maintenance And; Preparation For Service - Yamaha YTZ250S 1986 Service Manual

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ENGINE MAINTENANCE AND REPAIR
PREPARATION FOR SERVICE
Prior to beginning any work on the engine, take note of the following bits of advice;
they will greatly facilitate your engine maintenance and repair:
• Clean your machine as described in the General Information section entitled, "Clean-
ing and Storage";
• Group the parts of each component on individual trays, and arrange the parts in
the order of their removal;
• When replacing parts, always use the genuine Yamaha article to maintain optimum
performance, durability, and safety;
• All gaskets and seals should be replaced during engine work, and all gasket sur-
faces should be clean;
• During assembly, always apply oil or grease to bearing surfaces to protect them
upon initial start-up;
• Replace all circlips which are distorted from use or disassembly;
• Always replace cotter pins and piston pin clips after one use;
• Always clean and oil the threads of nuts, bolts, and screws during assembly, and
torque them to the proper specifications whenever possible.
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