Ash content corrolations to Pre-Ignition

[vex]

I'll check. I'm still looking, but I found an engine oil that does list it's ash content from the ASTM D 874 to be 0.88

http://www.nulon.com.au/products.php...day_Engine_Oil

That's rather high, and not good engine oil for our motors... so beware.

http://www.api.org/certifications/en..._Oil_Guide.pdf

Is a good guide, but only references Ash in the CJ-4 rating.

Still looking:
http://www.purvisbros.com/supduty.htm
Pennzoil Supreme Fleet Oil has 1.4%

There's a second good reason you shouldn't use car oil in your motorbike - sulfated ash. It's common in many American & Canadian modern oils; without burnt oil discoloring it, it normally has a light-gray to pale-tan colouration which may become visible if you shear a bit of the debris. When coloured by oil, it looks like the dreaded sludge. Unfortunately, the API SH-SL ratings are not strict enough on sulfated ash content. It's an issue that's fairly well known in some motorcycling circles, and the Japanese motorcycle industry recognized the issue very early on, creating a new oil specification specific to their needs (one, that among other things, caps the sulfated ash content very low): JASO-MA, recently revised further into to JASO-MA1 & JASO-MA2. For motorcyclists, the sulfated ash content poses a secondary issue: it means higher quantities of sulfuric acid if water gets introduced into the oil (such as from condensation within the galley spaces); since most motorcycle engines share the oil with both the engine and the transmission, the sulfuric acid is particularly problematic as the metals used in the transmission selector forks are made of cheaper steels that don't stand up to the acid nearly as well as most engine components.

The most informative I could find so far.