Piston char

[onlyonelife79]

So. Char on the piston is signs of to much detonation for the application/build ? Obviously if your running to hot, say 50/50 or straight race. A good sign of you running to hot would obviously show on the piston and in the dome right ? If I see small signs of char on a piston, but dome is in excellent shape, should I be concerned or change dome size/fuel mixture or is it normal for the piston to char over time ? How long is any char expected. Yes. I understand there is fire blast in there. I imagine blast areas take a beating.

[sprinklerman]

Google " piston wash".  You find all you need to know there.

[sheerider11]

Here is a low hour motor I parted out. Tht set up was good, could of went down a jet but still rideable. That's piston wash, I'm sure you can figure out what and why.

[onlyonelife79]

So. If you went down a jet, would that clean up some of the wash here in the photos? My pistons look the same with the small char in the middle, but not as much wash. Visually, does the amount of char build up, even if only in the middle a sign of running to hot ? Obviously char build up is from heat baking the oil correct ?

[slobanshee]

In for info*

[onlyonelife79]

Ya. As I gain education and opinions through working through my bike and reading the forums. I can be a contributed too. Jack ass.

[sprinklerman]

So. If you went down a jet, would that clean up some of the wash here in the photos?

 No . Just the opposite.  Google " Piston Wash" then read what comes up.

[onlyonelife79]

Thank you.

[camatv]

i'm taking it by car you mean carbon buildup.

 

on gas thats normal.  to make is simple  the underside of the piston is cooler than the piston top  your jetting dictates how much carbon builds up, the ports dictate how the shape of the carbon build will look like.  mix oil can also contribute a LOT to carbon build up.  927 is some nasty stuff.  some of the synthetic is a lil better  best carbon build ( or lack of it)i have seen is from another oil. 

 

that "heart" shape is actually pretty dang good.  you can see the ports fuel movements across the top of the piston.  that can tell you a lot really.. 

 

most alky motors wont have any build at all.  sometimes if they have some time on them just a light brown color on the piston top