Not bad. Getting fat on tacos. Doing the BR319 in the rainy season would be tough. The muddy rutted roads would be difficult and slow going, but I think your biggest problem would be the bridges. They rebuild a lot of those bridges every year for the dry season and let them wash out in the rainy season. I think your biggest issue would be hitting a washed out bridge over a river that you just can't cross without a canoe and then not having enough gas to back-track leaving you "up shit creek without a paddle." Also, if you're missing even one bridge there will be zero vehicle traffic to get you out of trouble. There's also the possibility of long sections of road being completely flooded. I vote that you make some inflatable pontoons. Bonus points will be awarded for either tyrolean traverse of the bike over water or full disassembly of the bike down to major components, portaging it piece by piece and reassembly on the opposite bank.