I have a 01 grizzly 600 and I rebuilt the top end and I followed everything by the book. Everything goes good until I torque the valve cover down and the cam or something binds up and you can not turn the motor over. If you leave the left side of the valve cover loose or just snug the motor turns freely. I’m at a lost can someone please help me. Thanks. The things I have done to top end. Everything is stock new piston new valves new valve seals new rings and new cam chain. That is all I have done to it so far. With the valve loose I can turn it freely all day until I torque it down. I’m stumped. Any help greatly appreciated

 

I have never done one so was waiting for someone else to come in, but as nobody has. The set up is unusual for a Yam, most have a side plate on the head so you can see the cam sprocket & timing mark with the rest assembled. I assume you have checked for any dirt etc, between cam journals and camshaft. It could be that decompressor, from parts drawings it looks like you have to assemble it up as you fit the timing gear. If so, you may have got something wrong there. The cam chain tensioner must be fitted last, after the cam cover. Cam chain guides can be difficult to get into their slots, are you sure they are right?

 

Thanks for the reply. I have had everything ultrasonic cleaned and everything is spotless. I have assembled and disassembled everything 3 times now and have done everything by the book. Also I can leave the cam chain tensioner out and as soon as I torque the valve cover down I get the same results and it will get jammed up like it’s getting smashed or binding somehow.