Yamaha Raptor 660, 700 Repair Manual 2001-2012

The 2001-2012 Yamaha Raptor 660, 700 DIY repair and service manual by Haynes, covers:

• Yamaha Raptor 660, 2001-2005
• Yamaha Raptor 700, 2006-2012

Book Excerpt: 2001-2012 Yamaha Raptor 660, 700 Repair Manual GENERAL ENGINE OVERHAUL PROCEDURES

CYLINDER COMPRESSION - CHECK

1. Among other things, poor engine performance may be caused by leaking valves, incorrect valve clearances, a leaking head gasket, or worn piston, rings and/or cylinder wall. A cylinder compression check will help pinpoint these conditions and can also indicate the presence of excessive carbon deposits in the cylinder head.
2. The only tools required are a compression gauge and a spark plug wrench. Depending on the outcome of the initial test, a squirt type oil can may also be needed.
3. Start the engine and allow it to reach normal operating temperature, then remove the spark plugs (see Chapter 1, if necessary). Work carefully - don't strip the spark plug hole threads and don't burn your hands.
4. Disable the ignition by disconnecting the primary (low tension) wires from the coil (see Chapter 5). Be sure to mark the locations of the wires before detaching them.
5. Install the compression gauge in the spark plug hole (see illustration). Hold or block the throttle wide open.
6. Crank the engine over a minimum of four or five revolutions (or until the gauge reading stops increasing) and observe the initial movement of the compression gauge needle as well as the final total gauge reading. Compare the results to the value listed in this Chapter's Specifications.
7. If the compression built up quickly and evenly to the specified amount, you can assume the engine upper end is in reasonably good mechanical condition. Worn or sticking piston rings and worn cylinders will produce very little initial movement of the gauge needle, but compression will tend to build up gradually as the engine spins over. Valve and valve seat leakage, or head gasket leakage, is indicated by low initial compression which does not tend to build up.

Subject: 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Yamaha Raptor ATV service, maintenance, repair. ISBN-10: 1563929775 | ISBN-13: 9781563929779 | Haynes 2977