I just used a dremel tool. I didn't make a very big slash because the crank is pretty hard and the stone was wearing fast. Probably a good idea to put a piece of fuel tubing over the crankpin so it doesn't get nicked, and steady the dremel with on finger resting on the crank so it doesn't slip. I think the next time I will make two slashes centred on the crank at about 20 degrees and flared out like my Fora .049 is. Those guys seem to know what they are doing more so than the car guys IMHO at least for WOT applications. I think the FAI Speed motors have something similar too. I think the radius on the rod made more difference than the slash though, it removes mass and lets the fuel go by easier. I hardly put more than a .015" rad on and polished it with just 600 sandpaper. I will get a pic. when the wife gets back and after I go flying. She will be gone for three weeks with the camera on Monday so I better not forget. edit. Jeez, I charged up the radios and two planes. both on channel 54, and they were the wrong radios. I have three on 54 and one was Airtronics. Senior moment, and no flying today. The first pic is the Fora .049 turbo cut. The ASP .15 head and the OS LA .15 ar pretty much interchangeable, but the ASP/Magnum head seems to make a bigger change. Likely because of the bigger ports and ball bearings.
Last edited by aspeed; 09-28-2013 at 01:34 PM.