The burned piston could have been because of flaws in the BB kit. Most BB kits are junk (especially the pistons). They are a cheap alternative to a rebuild since OEM P&C's are pretty expensive. But if you do use a BB kit from any manufacturer... always... ALWAYS... use the factory Stihl wristpin clips. The clips that come in the kits are junk.
A lot of cats have used BB kits with no issues. But you couldn't pay me to use one.
50:1 Stihl Ultra with 92 octane fuel will be fine in any saw you run. Period. I use it in Everything from my old McCullochs and Homelites to my newer Stihls... no probs. I think it was Brian (da Skwerl) that said it best a while back... "Saws have a lubrication requirement... not a set oil amount requirement." I might have murdered that quote... but the concept is that modern mix oils do not have to be mixed at barbaric ratios to achieve the lubrication requirement of older mix oils. Before mix oils were used... SAE 30wt motor oil was the standard at 16:1, 20:1, or 25:1. But I can achieve the same lubrication with a 50:1 full synthetic mix oil nowadays.
Clear as mud?
Gary
