Just picked up a 73 Dt 250.It is in average condition and it ran when I picked it up. I got it home and did some cleaning(airfilter, oil change etc...) and when I tried to fire it again she started right up, ran like I had my hand covering the aircleaner, and stalled. All I can get it to do now is backfire(ouch)! Did my points crap out on me, or do they just need to be re adjusted? Any help would be great.