Hello, fairly new member here, posted a few questions regarding my 77 90. I just picked up a really clean 1985 ATC 70 from guy at work. He's owned since 1989. It's been sitting for at least 15 years. He did drain the tank and run the carb dry. My first attempt to get it running was I replaced the rock hard fuel lines, poured new fuel in it, and three pulls it started, but leaked fuel everywhere. Also, I wouldn't rev, but I contributed that to the completely clogged unit filter. I have since completely cleaned and rebuilt the carb, twice at this point, flushed the tank, although it is spotless inside to begin with, and installed a new uni filter. The thing fires right up, idles great, revs good for a while, then starts popping and backfiring, when I ride it it seems fine until the rims come up, then does the same thing.
1. Questions- what series carb is this so I can order correct parts, jets, etc?
2. Should I increase the main jet size? I don't know what it is, assuming stock, what is stock?
3. I read also I should adjust the needle to richer it up?
4. What else should I do?
5. Soon I will be putting on a Spangler pipe, assuming it will need to also be rejected then?
Can't figure out how to load pictures? LOL!
Thanks!