Possible clutch shoe problem?

Just spent $40 more today on the Savage. everything ran good, fired second pull, all screws had lock-tite, temps were good, i had new glow plugs. then i as i was running the fuel out of the third tank, I noticed the engine started seeming like it was bogging down. It didn't seem like it had enough power to get going. just sort of lots of smoke, but really slow acceleration... then i could swear when I checked it out i saw smoke coming from the clutch area. could it be the clutch? A fried motor? doubting it was the slipper clutch. and I have never adjusted the 2 speed... I don't think it would be the two speed because it wasn't pulling wheelies like it usually does. If this is related to the shoes, is this as simple as replacing them? I have done so much for this truck and I'm really getting tired of taking it apart.