Just bought a 2000 blaster and it needs some love. Carb looks new and i cleaned it but would still bog in the upper rpm's. Also no 5th gear. Upon disassembly It looks like the balance ate into the case and also there is a crack any suggestions? Could a shop weld/ grind to fix this. Also it looks like it was rebuild poorly before I got it. What all should I check before reassembly. Any help would be Greatly appreciated.