Well if I were you I would part it out. But if you want to rebuild I just did mine its the exact same sled and you can do it on a budget but it takes some internet shopping. First off I doubt your pistons are ok so if you cant determine that ask a mechanic to take a look. You will also need to pull the motor and inspect the inside and outside of your crank. If the crank is out get new bearings for it and have it trued. If the crankcase is cracked have it welded by a pro, make sure they know it cant get warped. Bring the crankcase to the guy that does the bearings and trues it and have them place the crank in the case immediately after the work is done. You can get a mono cyclinder, its both cylinders in one mold, if you cant afford that you can find some used ones on ebay maybe. I got a SPI top end kit for mine and its ok and fairly reasonable. It doesn't come with piston bearings so get the oem bearings from your dealer. Also get a full engine gasket/seal kit from somewhere. Also you need to download the service manual and get all the proper torque specs and it will help you with tear down and rebuild instructions. I will recommend that you send the crank case and crank to Steve at Parris Racing here in Belgrade Montana and have him work his magic it will cost around $800 bucks but well worth the extra power and engine longevity. Now inspect the clutches and replace all the bushings, rollers, pins, buttons, weights and springs. I would order slp clutch kits for your elevation. Inspect all the coolent and oil lines. Replace the fuel filter. Replace the voltage regulator. Check your tps sensor and make sure your oil pump is set correctly.