I have bought a raptor and I can't figure out what the problem is with it it is a 660 raptor that sat for 2 years. Drained the gas and carbs and got it running. When it idles it is alright but touch throittle and it back fires and sputters pipe gets red hot just reving it up. as soon as you crack it wide open it is just sputtering and back firing I've cleaned carbs and still same thing

 

Check the timing, but don't assume the carbs are up to speed yet. They may need adjustment. Also, what altitude are you at? That may require some adjustment to compensate as well.