Engine Rebuild

[QuadRacr57]

When I start my 300EX, if i blip the throttle, a little bit of black smoke comes out. It is a 1996 and hasn't been rebuilt yet, do i need to rebuild the engine. I think its the rings, but since i have then engine apart i would probably bore it out and put a cam in. So does this sound like i need to rebuild it? Thanks

[tater_kamik]

if it hasnt been rebuilt, i would say that probably needs to be done! i would definately give it a little bore so that the surface is good, new piston (obviously if you bore it) rings, clean the carbon off of the head, and do valve seals etc.

[Old Head]

well black smoke would be a rich condition but if you would prefer to rebuild it wouldn't due to the age of the motor.