No this is all relevant to my original post. Airraptor, I guess my question is how often do you take down a racing engine to clean it up ? As in the original post, the entire inside of the engine was pristine clean EXCEPT for the exhaust valve. I have tried CY 30%, CP 30%, and now have Rotor Rage 30%. At least these three carbon up the exhaust valve. AND yes in the summer especially I have changed to a colder plug. In winter (maybe 50~70F), I use the standard YS/OS 4-stroke plug. In summer (80~107F), I have tried an Enya #3,4,5,6. Last summer I used the Enya #4. Idling is not a problem. I have the SwitchGlo Pro the turns on at 1/4 throttle and below.
I think racing is close to my application. What oil do you use with 70% nitro?
The YS 80S has a short pancake piston with a cutout in the top of maybe 10 thou. It runs really smooth at 14,000 rpm. I have accidentally run a YS 70S fast enough to float the valves. Weird goose honking noise! Dave told me that people were running 18,000 on the YS 63 with stiffer valve springs long ago with 70%. What glow plug were they using ?