Well, heat may help, but I use an impact with a really good quality philips bit that fits the screw perfectly. Pull the trigger on the impact just a little while pushing the impact into the philips screw as hard as possible. It won't take much to get the screw to start to come out.
If you don't have access to an impact, there is another solution that works just as well. Using a small chisel (yup, I said chisel) and small hammer, place one edge of the chisle on the outside of the round head on the philips screw and tap the chisel with a hammer. A few taps should do to get the screw started out. I was forced to use this method at a National Hare & Hound several years ago when my oldest son lost the motor on his new KX500 during Saturday practice. Fortunately, the Kawasaki semi had a spare cylinder and head gasket, but we had to swap all of the parts from one cylinder to another. Unfortunately, my nitrogen tank in the van was dry from tire changes, so couldn't use the impact. The small chisel and hammer worked just fine.
As a note, all this talk of power valves got me all lathered up, so last Saturday, we selected a couple of action movies to watch while we pulled the motors apart on both the 125 and 500. Boy, I didn't think it had been THAT long since I cleaned the power valves, but it was certainly time for a cleaning. Even slapped in a set of new rings just for giggles. Since is was rainging on Saturday, we just spent the whole day working on the bikes watching Clint Eastwood kick some criminal tail.
On Sunday, it wasn't raining, so we headed for the desert for some motor testing and suspension tuning on the 125. WOW, what a great day. It's a blast having the boys eight years apart, as I have had a riding partner for a lot of years. Unfortunately, the youngest was able to get around me in a sandwash on his little 125. He's so good in the corners, I was forced to protect the inside lines in every turn, so he had to try and pass on the outside. After several miles, he was carrying so much speed into every corner he was railing the corners up the outside walls. I was having to drift from the inside to the outside in almost every corner, never shifting below 3rd. I even drift out wide a couple of times so far that I almost drove him right out of the wash. Much to my chagrin, the boy was able to pass me in a huge corner. Don't think he ever shifted out of sixth gear as he inched by the big 500 still railing the inside berm. While he wasn't able to get away for big green, he is so good in the corners, I wasn't able to put a pass back on for the lead. Way too much fun...
Good luck on the continuing power valve rebuild.
Rick
