piston burn pattern

[Speedfreek]

Hello,
I just pulled my 88 yz250 cylinder head off after about 5 hrs of riding time since rebuild. I usually ride trails and deep sand. I run amsoil synthetic 2-stroke oil at 40:1 My question is,why do I not have any deposits or burn patterns on my piston crown ? Is the bike running to rich,or is it because of my oil choice(low deposits)? The piston looks like it did when it went in the motor,perfectly clean. Any help would be appreciated.
Thanks :ride:

 

[marcusgunby]

Too rich tends to wash the piston crown.

 

[Speedfreek]

Thanks for the reply Marcus, I'm leaning towards the rich conclusion as well since the exhaust port and powervalve were black,not with build up,but black and a bit oiley. I didn't have any spooge at all in the silencer which is what I would exspect if it was that rich though.I'm attempting to learn how to set up my bike so any help would be great.

 

[Woods428]

Speedfreek,
What does the head look like? I would also recommend taking the cylinder off and looking at the sides of the piston. If you have ANY streeking of black, brown or light brown that can also meen you are too rich.

 

[Speedfreek]

No streeking of black on piston.The piston and cylinder looked exactly like it did when installed(new & clean) except for a light oiley coating.Head was clean too.

 

[cujet]

Maybe not enough time on the engine?

Heavy use of oil will also keep an engine clean inside. If you are running more than 32 to 1 with a good synthetic, expect a clean engine.

Chris