my 1977 honda xr75 dirtbike has been barely starting and when we do get it started it backfires, and cracks and kills itself, im thinking it needs a tuning on the carbuerator, but that didnt help anything please help!
Usually this is a dirty carb. There are two jets, low speed and regular. The one with the needle that goes up and down into it is the regular jet, and it’s less likely to be plugged. Next to it is the idle jet, and it’s easy to plug up with crud. You have to take everything apart and clean it out, very carefully, with solvent and a very fine needle and compressed air. If you have experience it is fairly straightforward; otherwise you need a service manual.