Solve what caused it first.
Air leak,
Low octane for compression,
High ignition timing,
or all of the above + over heating.

That piston edge sure looks like low octane damage.
Neil

 

Also could be a coolant leak....bad head gasket or warped head

add it to the list of things to check

 

Thats what my piston looked like when using the CR head gasket without using race fuel. Or as Niel put it "low octane"

 

Thats what my piston looked like when using the CR head gasket without using race fuel. Or as Niel put it "low octane"

Yeah, I just cringe every time I hear about somebody using pump gas in their beloved 250R, man that stuff is junk.

Now I REALY cringe, when I pull up the the pump & got to fill up MY motorhome with that 10% crap.
Be pulling a hill & I can just about hear that V10 crying, "man you killing me here, need some REAL gas".
StaBil, has an additive that is good to mix with that crap, one they offer for outboards not the regular type.
Lucas has it as well & cost about the same as the StaBil.
Neil

 

I even "cringe" when customers tell me they run Race Fuel out of a pump and not a sealed can…you just never know what comes out of the ground…water, contaminants, unknown chemicals, what octane rating are you really getting…I bet is it lower than rated.

I much prefer to purchase a sealed can of Race Fuel, yet I know it is not conveniently available to everyone; it should be....Would save a lot of melt downs IMO.

Carlos.

 

QUOTE(acecarlos @ Jun 30 2011, 04:35 PM) index.php?act=findpost&pid=75064I even "cringe" when customers tell me they run Race Fuel out of a pump and not a sealed can…you just never know what comes out of the ground…water, contaminants, unknown chemicals, what octane rating are you really getting…I bet is it lower than rated.

I much prefer to purchase a sealed can of Race Fuel, yet I know it is not conveniently available to everyone; it should be....Would save a lot of melt downs IMO.

Carlos.

How long does race gas last if its in then can after its been opened? I've debated about switching but don't go through allot of gas in a year.

 

If it is in a control temp area, can last a good while. Temp change & it expanding & contracting, soon or later it will drew moisture in & not long before it will start going bad.
Neil

 

If it is in a control temp area, can last a good while. Temp change & it expanding & contracting, soon or later it will drew moisture in & not long before it will start going bad.
Neil

Years ago we tested octane levels of C12 left on a shelf, we tested a can that had been opened and one that had not. The first test was when both cans were new and the second test was at 6 months and 12 months.

We only saw 1 octane point difference between all the tests...now; both these cans were kept in a storage room (50-80 degrees) and on a shelf 24" off the ground.

Carlos.