Yamaha Raptor 660 R Top End issues 

Where did you get the Manuel from?

2004 2005 ??

Good video! How did you keep the motor from trying to turn over when blowing in the air on the leak down test?

I'd be willing to say the decompression valve is holding the valve open

wow someone beat that poor motor hard , i have a raptor with popping issues i hope it's not like this inside . that auto decompression makes me nervous because i have a harmonic vibration coming from the cam area so i am worried lol good luck & best wishes