I have recently had a rebuild ( picture ) and there's not much compression as it's easy to kick over. What could it be? Also I had the valves checked and was told they were in spec, yet it's hard to start when hot, does it need re-shimming? Finally, it bogs quite a lot. When I snap the throttle back while at idle and pulling off/out of corners without high rev's. Would the ap mod help this? Other than these, it's goes quite well. Any help would be appreciated.