I have an '81 Honda Cx500 custom. I am having some issues with her though. When I am in gear it won't go over the 3 on my rpm gauge. It hits about 2 1/2 and then kicks around and starts to buck like a bronco. I have some backfiring when it starts, when I have it in neutral it seems to be able to rev over the mark and not run too hard. Any ideas on what might be going on? I am not too technically proficient but what I imagine it is something to do with a carb or fuel, as it starts just fine.