My magnum ran amazing for two days with everything fresh out of the box kit pipe carb. Tried a different plug for some fine tuning and was significantly worse put my old one back in and over the day it's been running crappy. slow acceleration average mid speed and at full throttle it'd slow me down like four stroking so I down jetted and it wouldnt even run. Then a buddy suggested up jetting and that was worse so then I put my original jet back in and it runs horribly like won't go more than five miles an hour.