for the sake of research thought it might be interesting to show my venom 14.25:1 98mm piston after 15 hrs of use with the 1 quart kemco tetrathyl lead additive and 93 pump gas mix.
it was run with the hr+3mm crank in a YFZ with Venom porting and pipe. Very strong setup.

i'm not an expert and would like to see what everyone thinks of it's condition related to predetonation as i would like to learn something.

try not to pay mind to the valve marks

That looks normal..... If you put it in a parts wash itll be back to mirror finish almost..... but yeah thats a little bit cleaner than my 12.25:1 looked like and its been in there over a year

what would predetonation look like?

There is preignition and detonation...... not predetonation. but you have neither. pim pretty sure preignition will burn a hole through ur piston from the spark plugs and detonation jus sorta cracks or balls up your piston. I have never had either only seen pituces so i may be alittle off but i know you dont have either. Clean the carbon off that thing and itll be nice

thanks for the insight.
i mainly wanted to show a piston with this type of home mix race gas and that it is working just fine. some folks are skeptical about it, but it seems to work fine.

keep in mind with the crank youve upped your compression...

piston looks fine other than what appears to be valve contact there...

have you ever dyno tuned? i ran the same fuel myself with over 14-1 and my pistons usually come out a little lighter but i dyno tune pretty regularly

yeah i was at 14.85:1 with piston / crank combo. whichs is pretty high. that's why i wanted to post this and learn from peolple who know more about this than me. i was told the kemco product would work and it looks like it did it's job.

i never did dyno tune. probally was about one main jet rich though. didn't have access.

I'm working on rebuilding it now as i obviously had some issues. hoping to have it back together by april and i may try to make the journey to michigan and take advantage of the dyno tune day. thanks