Yamaha Viper 2 stroke snowmobile top end

How to take top end off and reassemble on a 2002 Yamaha Viper snowmobile and most snowmobile engines.
1. Remove spark plug wires and spark plugs.
2. Remove coolant hoses and wire harness from the head. Make sure you have a pan underneath the sled to catch the coolant.
3. Remove all the bolts from the top of the head, use a baggie to keep this hardware separated. use a rubber mallet if necessary to pound the head up and remove it.
4. Remove the three power valves from each cylinder by removing the four Allen bolts from each cover. Pay attention to which way they go back in, the cover has a tab on it, and the valves should go in with the longer side on top, clean them before putting them back in.
5. After removing the exhaust pipe, remove the exhaust manifold bracket by spraying penetrating oil, then using a 10 mm socket or wrench to take all the nuts off.
6. Remove the four nuts at the top of each cylinder, then using a rubber mallet tap the cylinders up and off the pistons. Try not to get excess coolant into the crank.
7. Place a rag underneath the piston so as not to drop anything into the crank, remove the piston pin clip, slide the pin out, remove the piston and bearing. Check rod for excess play, cylinders for wear.
8. Make sure everything is lubricated well with two stroke oil. Place new pin bearing in rod, a pin clip in one side of the piston, slide the pin through the piston and rod bearing, install the other pin clip. make sure the arrow on the piston is facing towards the front. make sure the base gasket is in the proper position, Slide each cylinder over the piston and rings by compressing the rings with your fingers, talk each cylinder according to specs.
9. Replace head and gasket using proper torque specifications and sequence. check compression, put a little bit of gas in each cylinder, replace spark plugs and wires. Start the sled.
10. Bleed air out of cooling system until all heat exchangers are warm.