The 170 CDI does not sell "stock". One has to get the regular "low oil" 170 (I got mine 3 weeks back from Central Hobbies) and the CDI kit separately. The CDI kit is freely available in many hobby shops in Japan (I got mine on a visit to Tokyo). Various posts say that one can use 9% oil (or 7% or 10%). Most people on this forum seem to be using 20% or more Nitro. The Nitro just controls the power and so should not matter with the CDI engine as much as it does with the 'regular' engine.

I have not run my engine yet (Though YS Parts and Service did run it for 30 mins or so - I sent it to them to fix the CDI kit). I will only get to run it after another two weeks or so. I'll let you know how it goes. Plan on using 9% oil and 15% to 20% nitro. I'm putting it on a Somenzini Yak, and a second one one a TOPMODEL CAP 232.

Atul