I made a really bonehead mistake of putting the piston in backwards when rebuilding my 97 RM250. It didn't help that the arrow on top of the piston was worn off (and I really did not know about the design of the piston then...........I do now though). On top of that, the exploded diagram of the cylinder and it's parts (in the manual) shows the piston backwards in the picture!?!!?!?!?!? WTF?
So, the bike ran decent considering the piston was backwards, but didn't have good top end power. We tinkered with the power valve until discovering in the actual polaroid pictures in the manual that we put the piston in backwards.
When we took the jug off.....we found the damage though. The ring gaps snagged the exhaust port on the power stroke and popped a chunk off the piston. The chunk appears to have passed out the exhaust (no scoring down the side of the piston/wall and crank moves freely + no chunks in oil).........but it left a gouge in the cylinder.
The powervalve that sticks into the exhaust port has a very very tiny scrape....probably nothing. But around the edge of the exhaust port is a chunk of the cylinder wall gone. Its about the size of a pencil eraser and as deep as the width of a finder nail.
So what can I do now? I'm looking for the least costly fix. Can that spot be welded or coated over (or both). Who does the most reasonably priced work? OF course I also need a new piston, wrist pin/bearing, and rings.
Thanks for the help and don't beat me up too much...I already did that to myself.
Micah
So, the bike ran decent considering the piston was backwards, but didn't have good top end power. We tinkered with the power valve until discovering in the actual polaroid pictures in the manual that we put the piston in backwards.
When we took the jug off.....we found the damage though. The ring gaps snagged the exhaust port on the power stroke and popped a chunk off the piston. The chunk appears to have passed out the exhaust (no scoring down the side of the piston/wall and crank moves freely + no chunks in oil).........but it left a gouge in the cylinder.
The powervalve that sticks into the exhaust port has a very very tiny scrape....probably nothing. But around the edge of the exhaust port is a chunk of the cylinder wall gone. Its about the size of a pencil eraser and as deep as the width of a finder nail.
So what can I do now? I'm looking for the least costly fix. Can that spot be welded or coated over (or both). Who does the most reasonably priced work? OF course I also need a new piston, wrist pin/bearing, and rings.
Thanks for the help and don't beat me up too much...I already did that to myself.
Micah