ORIGINAL: Freddy Warbird
I bought a DA 50cc for my Katana and have 34 flights on it now. I bought the engine in January, 2005. This one I think has the update with the fuel line. Its been running fine. I have 3 1/4 gallons through it, and the only "querk" I have with it is @ 32:1 with 91 octane shell gas, there is some pinging at WOT. The engine has full power on the up lines for a slightly rich setting, and I know its not overheating. My theory is its the gas. I know it is not recommended, but I added the correct amount of 104 octane boost for one gallon of gas which is .8 ounces or 4/5 of an ounce to see if the pinging would stops sence the timing is controled by the box. The engine ran fine, But, the one flight, that I got in yesterday, was with some other guy in the air sceaming his 33%cap 232 with a DA 100 at WOT. In additon to the wind, it was too loud for me to hear my own engine, so I could'nt here if the pinging went away. Now it raining. maybe tomorrow.
I don't want to start a long-ish argument about this "ping" problem but as far as I know, and it's been written about in many articles in many magazines, that octane just doesn't matter in the small cu. gassers as we use. Octanes as low as 70 will be just fine to use in a DA50, as it is in many small cu. motrocycle 2-stroke engines.
If you hear a "ping" then I'd be looking elsewhere, perhaps timing too far advanced but it aint going to be the octane of the gas.