Oil Burn Temperature


Jul 29, 2000
South America
I can't find any info about the temperatures at which different oils burn black onto the underside of the piston. I'm thinking that they vary by content of synthetic oil since is the most resistant to burning.
What got me started on this is the idea that after you get everything else right (plug heat range, timing, etc) then you adjust jetting for best power without risking seizing and that jetting to not allow the oil to burn onto the underside is a good rule but then entered the idea that different oils burn at different temps. I'll probably have to do some home testing.
Everyone has their own standards they go by but I think they base those standards on their own experience with fully or lightly seized pistons. So everything goes back to piston heat and I'm hoping there can be a standard regarding the oil color at the piston underside.
If you have any data to contribute to this thread then please do so. I just get tired of so many people talking like their standard is the only one. For instance there is a big difference between air and water cooled engines. Compression and max RPM are also big factors. Also outside air temperature.
Too many times I see posts of people displaying a photo of their spark plug color and asking peoples opinion of their jetting going only by that. Maybe within a group of the same type of engines with the same purpose that has some validity but some facebook forums are for any type of 2 stroke and so the groupie standards often go right out the window.