Amsoil 10W-40 MCF in a 2004 Yamaha YZ250F. Drained the oil with ~5 hours on the oil and 120 miles. The sample is from September 2005 Testing was done by Blackstone Labs 02/21/06 INSOLUBLES 0.2% WATER 0.0% ANTIFREEZE 0.0% FUEL <0.5% FLASHPOINT DEG F 420 SUS VISCOSITY @ 210 DEG F: 64.1 ALUMINUM 14 CHROMIUM 1 IRON 7 COPPER 3 LEAD 0 TIN 1 MOLYBDENUM 38 NICKEL 4 MANGANESE 0 SILVER 0 TITANIUM 0 POTASSIUM 1 BORON 3 SILICON 10 SODIUM 0 CALCIUM 3243 MAGNESIUM 23 PHOSPHORUS 1171 ZINC 1343 BARIUM 0 COMMENTS BY BLACKSTONE, EDIT: MY HANDWRITING SUCKS IGNORE THE YX250F REMARK! Another first for us -- The Yamaha YX250F. But we have seen many other Yamahas, so we based wear in the universal average file on a similar type. Your wear is better than average, which is a good sign that this Yamaha engine is doing just fine. The TBN of this sample read 11.8, so the oil was loaded with active additive. The oil was in good shape physically, containing no moisture, fuel, or other contaminants. The viscosity was just a little low, but it's not hurting anything. You could run more miles on the oil if you wanted. Nice engine!