gas/oil mixture questions...

[250RWANTER]

Okay, I noticed on most R's it is recommended to run 20:1. As I am reading and have talked/seen, most run 28:1 or 32:1 and some even 50:1. How do you decide when to take that next 'jump' up...especially 50:1. Is it for different types/brands of premix or? Seems like a big risk to lean it out that much?
Also, is it running rich if there is oil residue in the pipe/silencer? Or is that just normal on a 2-stroke?

Thanks.

[RichinMO]

As far as I'm concerned, the premix ratio is set by whichever type of oil you buy. If you use cheap stuff, you should keep it 20/1 to 32/1. If you use Bel Ray that recommends 40/1, do it. If you use $10 a bottle Klotz that recommends 50/1, do it. The higher technology of the oil, usually the higher ratio you can use. But once you find one the bike agrees with, don't go changing it just to be changing it.