I have a 1990 trail boss 250 that I have owned for a couple of months. It must have sat for quite a while before I bought it as it took me a while to get going. It ran just fine for about a month but now barely runs at all. It started by not having any power off idle, but it would idle fine. A friend said the carb had dirt in it so I cleaned that, it ran better with no bogging, but still not the power. A few minutes later it started up running rough and bogging intermittently and even backfiring a few times. After going over the carb again no improvement and now it barely runs at all. I am not too familiar with 2 strokjes so any help is appreciated.

 

Did you check the plug,Airfilter,Plug wire,Carb jets?

 

After checking what 2manytoys said then check your compresion it should be over 100psi if not its time to do a topend.