2006 Yamaha Motorsports Apex GT Owners Manual - Page 65
2006 Yamaha Motorsports Apex GT Manual
Page 65 highlights
WARNING @ G G G @ Do not drive the snowmobile with the shroud or covers unfastened or removed. Keep your body and clothing away from rotating parts when servicing the snowmobile with the shroud or covers removed. Do not touch the hot muffler and engine during or immediately after operation. CAUTION: @ Make sure that all cables, leads, etc., are in place when installing the shroud and covers. @ NOTE: @ When installing the shroud and covers, be sure to turn the fasteners and top cover bolts completely until they stop; about 1/4 turn after they are seated. @ ESU03681 Checking the spark plugs The spark plug is an important engine component and is easy to inspect. The condition of the spark plug can indicate the condition of the engine. Check the coloration on the white porcelain insulator around the center electrode. The ideal coloration at this point is a medium to a light tan color for a snowmobile that is being ridden normally. If a spark plug shows a distinctly different color, there could be something wrong with the engine. For example, a very white center electrode porcelain color could indicate an intake track air leak or carburetion problem for that cylinder. Do not attempt to diagnose such problems yourself. Instead, take the snowmobile to a Yamaha dealer for inspection and possible repairs. You should periodically remove and inspect the spark plug because heat and deposits will cause a spark plug to slowly break down and erode. Consult a Yamaha dealer before changing to a different type of spark plug. Specified spark plug: R CR9EB (NGK) 8-7