Running 40:1 in a 50:1 world.

[Fordiesel69]

One thing worth mentioning is strato port cylinder designs. If you are operating a standard 2 cycle engine, the entire fuel / oil mix hits the crankcase first, then up the transfer ports. When manufactures switched to strato port design, 20% less of fuel / oil mix gets into the crankcase. While this improves emissions, makes the exhaust cleaner, and lowers combustion temps to a small degree, why are we seeing crankshaft bearing failures? Partly is the 50:1 not providing enough lubrication for the bottom end components. Add in crank stuffers on the 550XP / 562XP chainsaws for example, even less oil is getting the the crank bearings and seals. This will speed up the failure.

40:1 really is the win. Plenty of protection, and no real trade off in anything negative. Anything equipment that is sentimental or not easy to obtain a replacement, 32:1 and you will need to tune the carb for it.

 

[Japanese]

Everthing I own runs on 40:1 and have been for over a decade. I used to mix my dirtbikes 32:1 and they loved it as long as you were on the throttle. Seemed to make more power.

32:1 is a universal ratio for dirt bikes, especially the air cooled ones. Usually water cooled and engines that use turbine cooling run 40:1 and 50:1.