Here is the mod that i did to my motor. I attempted to balance the crank while it was apart and stupid me didnt look up any info on it... So it now vibrates like all **** at 25mph. I didnt half the weight of the reciprocating assy. But not all was lost... Before the crankshaft and boost port mod i could at most do 34mph according to my speedometer. Now the same speedometer read 43mph! Now im not going to tell everyone that it is dead accurate since i do not have a gps to test it but i know im going approx 40 mph since i was keeping up with traffic... The crankshaft can only be holding the engine back and the sound of the motor at that rpm is very smooth. Current mods to my engine include porting intake and exhaust, expansion chamber, homemade glass pack and steel pack muffler, 44 tooth sprocket, NGK b5hs, polish the head and piston top, and 2 boost ports. The two ports were about 1/4" wide and are as long as the ceiling of the transfer ports. They are about 3/64" deep and are centered between the intake and transfer ports. The end of each port is angled towards the intake port and utilizes a steep angle to aim at the sparkplug and help scavenge the exhaust charge out of the cylinder. Im satisfied with this mod and would do it again but will be tearing the motor down again to install a new balanced crankshaft... Please excuse the poor grinding on the one port, they ran out of grinding stones at the store and i will clean it up on the next tear down