Jerry Mr Wildcat i recentily got some of your ys 20/2o blend. I am getting a new ys 110 soon and i am planning on using it for break in and regular use on the ys. I know ys doesnt recommend over 2 or 3% caster in their fuel but i thought for break in only i would mix a couple ozs per gallon for just a little added protection . I have been running ys motors for 12 years and have used every fuel from cool power heli to sig . Whats your opinion on putting a little caster in with your blend. I did notice when i ran some of your ys blend in my ys 63 it didnt put out much smoke at all. the engine ran great but i like to see a good smoke trail on my ys motors because of their high performance load.