Join Date: Nov 2009
Location: Abbottsford, BC Canada
cylinder size? blown head gasket look like?
how is bore size measured? I bought this 2006 Rhino 660 used and was told it was a 720 big bore. Didn't take long to blow head gasket. I wanted to get back to stock size. I bought a replacement cylinder & piston and was told it was considered one bore size over, so almost stock.
I measured the top of cylinder with my digital caliper. My OLD head is 101.6mm (4"). The replacement head is 100.7mm (3.96"). So how do those convert to bore size? I thought the 101.5 = 686.
ALSO, what does a blown head gasket look like? Mine looks normal to look at it, no obvious blow-out marks. I don't know what a blown head gasket should look like. I know there is all kinds of coolant on piston, but my oil level never went up, so wherever it leaked, I think it went into combustion chamber and burned off. In fact, my oil level would go down, and of course, I went through coolant like crazy. It would create an air lock on a short ride it was so bad.
when Yamaha manual describes disassembly, they say to take off cam sprocket. This is second rhino 660 I've done piston replacement on, and both times the cam wiggled out once the tension was off and exh side tension rail was removed, so no sprocket removal.