Last week I mangaged to thread my head button.

Today I fitted a new one and noticed my Cly head and the top off the piston was very pitted!!!![X(][][]

I have read in the thread below that is it due to too hight a Nitro content, I have been using 25%.
I will now switch back to 20% as my last bottle was, but will it be okay to run it with the pitting or will I need a new piston????

The compression seams to still be there.

http://www.rcuniverse.com/forum/m_23...tm.htm#2365609

yeah, to ohigh a nitro content or runn ing too lean will do that to you. I have seen many 2 stroke bike pistons get holes burned right through the top of the piston from running high octane fuel with a lean setting.

If the pitting is really minor, you should be ok to run it, although I would take the engine apart and give it a good cleaning (the missing metal has to go somewhere)

I didn't think it was too lean, its only on the base HSN setting (3.5 turns out), and smokes like a good'n. []

The only other change has been to run a ultra cool plug as this was the only way I could get the temprature down.
Could this have caused it??
Mind you, it has been stalling alot recently.

I guess I switch back to 20% as there was no damage after 1 gallon went through it and persevere.
What is the worst that could happen? Either way a new piston and sleave will be on the cards soon I guess. []