I had a honda lawn mower that had a bent crankshaft. I ordered a new shaft and put it in. However, after putting the engine back together it is kicking back when I try to start it. I timed the cam the way I have read that you should do with the piston being at TDC and the two marks on the cam gear being parallel with the the block. It will start and runs fine but sometimes when trying to start it, it will try to pull your shoulder out of its socket. Would having the belt one notch either too slow or too fast cause this? It has got me beat as I have tried everything I can think of and can't seem to eliminate the kicking back. I did check and the decompression arm is opening the exhaust valve up just a little bit to relieve the compression. Any help would be greatly appreciated.