Chainsaw Repair

again thats on a bike design motor , this is for chainsaw , crankcase is different and port degrees are different . Even type of fuel makes a big difference on how much horsepower each different pipe design makes  or rpms , How you make your turn with the header also changes the rpms of the pipe , main reason is some pipe designs you make each cone of the header , some pipe design you make the header all at once in a long straight cone first then cut into cones , each cut with a thin blade is .025 so by the time you finish cutting 13 or so cones you have raised the powerband a 1000 rpms over what you set your goal at , Another thing , a pipe is or should be designed by the type of transfer ports in the motor , the smaller narrow ports like a small taper header better as a big taper will over draw what the small  ports can feed , In a chainsaw most times its ported to pretty much max on port width and has a flatter port roof so most like the bigger taper and big dwell pipe , Alcohol is abit different than gas , most alcohol pipes are at 3.2 degrees , some are 3.4 degrees , bigger the degree taper the more fuel is needed and most alcohol saws are max out at 3.2 degrees if the ports are max out on size as well . My computer program is TSR which I donot believe you can buy any more , I think its the easiest to use as if you change 1 thing on the pipe the program changes the other cone angles to keep the pipe correct plus once you build your pipe it will print all the measurements to cut the pipe out of the metal type you are going to use , you even have to tell the program what thickness and pipe temp your using for the program to set the cone angles at . One thing thou , this program will always build you a pipe with a smaller degree header and dwell, you have to tell program that you want this degree of taper or this diameter of dwell