Belize
 

Belize has, without a doubt, the easiest border crossings of any of the Central American republics. No charges on entry, but a US$15 departure tax. Bike entered in passport, plus you get a certificate allowing you to drive in the country, at no charge. There is, however, compulsory third party insurance. But they don´t nap you as they do in Nicaragua and Costa Rica. It's up to you to get it. Cost: US$8 for 24 hours. Being an insurance phobe, I overcame my phobia and bought the minimum, 24 hours worth. At the three police checkpoints I was stopped, their first question was always for the insurance certificate. They seem to be on to guys like me.
If you're in a hurry, you can easily cross the country in six hours, including a pit stop. The main road is excellent. But many speed bumps slow you down. Belmopan is bypassed by a fast road. Belize City can be bypassed via Hattie's Place and Sand Point. Border procedures on both ends about 15 min.

Yeah the cops there will go out of there way to nab you for not having insurance. the first time i was pulled over after 6 months of riding through mexico was in Belize right after the border just so they could check for insurance.