So here is my modified 45.4cc stihl ms250 025 with the old style one piece crank from a stihl 021 that is alot lighter at only 14 oz. the stock one is 20 oz. I weighed the pistons and they were the same weight so I dont think vibration will be an issue , I hope I have not completed the prop shaft or the carb adapter , the total weight is only 38 oz. so far. The lightest motor I have found in this size is the evolution 45 at 45.5 oz. If I can keep the prop adapter and carb mount to 3.5 oz. I will be a 1/4 pound lighter than the lightest motor available on the market today.

Darin