Re:
Re:
Looks like the rings have broken and migrated up into the cylinder. While running, the bits of ring beat themselves between the piston face and the head, causing the pits. This is a very typical failure on the crossflows. If the cylinder walls are scratched, then you will need an overbore. At the age of your engine, an overbore may be necessary anyway-check the taper on the cylinder walls. Personally, I would not reuse the pitted heads. In terms of what you need to rebuild, new pistons, ring sets, powerhead gasket set, impeller, thermostat. The rods and crank should be OK. All parts you need should be avail from Bombardier. You can check out the original parts lists online at: epc.brp.com. See your local dealer. You will have a problem with replacing the head, however, as they have been discontinued long ago. They are frequently available used on Ebay. The heads on your 125 engine are unique and high compression. Make sure you find the same part number repl head. Your ability to use other powerheads is limited. The powerhead bases changed in 73 and I am not sure 73 and up engines will work. Also, check for spline and height differences on the driveshaft. The upper bearing housing changed in 73, so none of your ignition system will transplant. Your electric shift gearcase will present problems, as any newer engine wiring harnesses will not have provision for the lower unit shift wires. You really have two solid options, replace the powerhead in kind, or overhaul the one you have. You can get an original 1972 manual from Ken Cook Company in Milwaukee, Wisc. Call them, they will take your credit card and ship direct.
