Used hh 250ss no high gear

[Dban928]

Okay all I'm really new to this. Bought a used 2007 hh 250ss was told new battery and gas should run great. In addition to the battery replaced ingnition switch , shifter house, exhaust valve, gasket, some bolts, cleaned carb and pretty much whole rig. Now I got it started but only runs in low and reverse no high gear. Just wondering where I should start? Would like to try everything before cracking open the gear box