other than the throttle linkage and muffler parts, there should be 4-5 screws under the chassis that you need to remove. Id think they would be hex, but could be Philips. If hex, they could be 2, 2.5 or 3mm. If you don't have a set of hex drivers, it is time to buy a set. But you can just buy a set of hex keys from any hardware store, hex drivers are just easier to use.
It never hurts to shoot some PB blast on the screws first and let it set for a half hour before trying to remove them.