650 Xs ?

[MOTIONLINE]

Which one of theese pistons is from a 650 XS MERC?

[crazy horse]

The one on the left with the boost port window.

[Hounddog]

Sorry, to disagree. The original 650 xs piston did not have the power port. Over the years most rebuilds were done with the
later piston. They said it made no difference. I disagree again.
They did not work as well and didn't last as long. With the original pistons, stock porting, steel rings, 150 lbs compression, 20 to 1 av gas, turning 6800 to 7200 rpm, we have had zero problems and raced these motors for 3 to 4 years without doing a ring job.

[crazy horse]

I was thinking about the stock 650 3 cly.:rolleyes: