I have 2 YS170 CDI. For breaking I run a couple of 16oz tanks with 30% Cool Power fuel. For the breaking I used glow, instead of the CDI. I do it because on glow you open the needle to a richer mixture, and that way preventing any over heating. Also, for breaking I use a 18.1 x 10 APC prop. I use the same prop for the first 4-5 fligths, swithching to 19 x 11 later.
I use the foam cover clunker. When done with flying, I run the engine dry, and left the remaining fuel in the tank.
Last engine that I sent to YS Parts and Service, was installed the last day of 2012 Nats, and run without problems until about 3 weeks ago when started having some issues idling. It had a total of 278 flights.
Time that I reset pump/needle: 0

Very, very nice power plant if you do not screw around with it.

Good luck

Rene