Fly wheel weight is not going to help you in that area. If you are using a torque pipe you should be seeing a little improvement on the low end power compared to the stock pipe but if your looking for real low end grunt you will need to change your front or rear or both sprocket sizes. Stock it comes 13(front) / 47(rear) which makes the bike have great overall power but the low end is weak at best. To keep the wear on the chain good, I recommend changing both sprockets and chain at the same time. I was using 12 / 50 on my KDX when it was a 200 cc and man it was a torque monster, 13 / 50 would even make a big difference. As far as your log flipping technique, you will want to practice taking logs in 1st gear using the clutch alot and as little throttle as you can. Faster just means falling harder in that scenario. Unlike the 4 stroke with a 2S you need to get your clutching down to a science, you can't use the clutch enough and makes the power more controllable. When you can tackle them in 1st, then start using 2nd but any gear you are in is going to be about knowing when to clutch and knowing how your bike reacts in the different throttle positions. Good Luck with it.