Motorcycle Repair: 1978 YAMAHA DT400, yamaha dt400, head bolts

Question
I JUST PUT A NEW TOP-END IN, AND I'M STILL GETTING ALOT OF ENGINE NOISE, IN THE CYLINDER. MY OLD PISTON WAS'NT CHEWED UP ON THE CROWN, SO I DON'T THINK MY BOTTOM-END IS BAD. HOW MUCH NOISE SHOULD I EXPECT? AFTER BREAK-IN, MY SPARK PLUG LOOKED GREAT. IS THE IGNITION TIMING OFF? WHAT ABOUT THESE SEALING WASHERS THAT GO UNDER THE SPECIAL NUTS THAT HOLD THE CYLINDER ON, THEY WERE NOT THERE WHEN I DISASSEMBLED IT? PLEASE HELP, THANK YOU.  CHAD

Answer
Chad,
Shouldn't worry too much about those sealing washers, just be sure the head was torqued on to the right ft. lb. reading and in the right order.  After a 1/2 hr. of operation, retorque the head bolts.  This step is overlooked by many.  I can't say much about the sound w/o hearing.  There typically is some high pitched ringing to be expected.  If it idles ok and doesn't misfire through acceleration you should be OK.  Compression should be between 50-80 psi.

Mike