Just got back to this thread. On earlier various post that you put up about the MMT buildup and considerations, I really didn't think it was a big deal BUT on that 3'rd picture down from top with the two exhaust valves side by side you can see MMT deposits on the SEAT. Now that can lead to hot spots and buildup a flame could travel through and burnt valves, plus at the least, the loss of compression from 'burping' through dirty seat with enough buildup. I thought it was just a covering of the chamber and valve surfaces and an aesthetic issue, that's why I was thinking no big deal. But now...I think I'm off the additive. EXCELLENT info and photos as usual.