Hi i guess this may be running to rich i'm not sure... but i have just run in an RBWS7II and while racing today i noticed after i put in the ARO that the plug was sooty & the top of the piston looks the same could this be simply running too rich, it was however running (imo) a bit hot earlier so i did richen it a bit as i was worried prolonged use racing today may have damaged the liner & piston, but can it damage it also if running a little rich for too long, not sure if it's the top or bottom end needle which is wrong, but i need another opinion as this was not a cheap engine to purchase,i am using Tornado 25% with a no.8 o.s plug

oh btw UBERCHAVALEX NEED NOT REPLY TO THIS POST AS I FIND HIM OFFENSIVE & HIS ADVICE USELESS !

Thanks in advance people

i noticed that my plug was like that to. and im also running rich. i dont know if its a problem. i dont think it is anyway

If you run to rich there will be NO deposits on the piston or anywhere else in the combustion chamber.
The ideal setting should yield a slightly brown/golden surface that can be wiped away with paper.

What does the filament in the plug look like?

If it's shiny and straight you are running on the rich side.
If it is slightly silver-dull you have tuned the engine for maximum power.
If it's pushed-in/distorted you are lean.

This assumes you put a new plug in before this run. Otherwise it will be hard to diagnose.

Hi the plug was sooty too black and oily...i will try & tune the engine again tomorrow, i did take the head off and clean the top of the piston & change the plug we'll see what it does tomorrow, my final may have been something to do with it maybe i ran in 3 finals (1 hour non-stop) could have been the problem, maybe running rich for proloned peroids burns the oil that is hanging around...i'n not an expert but more suggestions would be welcome

Thanks guys

With an attitude like that you can count my help out as well

yeah but he's got a point though

LOL