i just bought a kx250 2003, bike starts up very good first kick runs no problem at all, i recently changed the mixture from 32;1 to 40;1 the guy i bought it from ran it at 32;1 and it leaked black oozz all over, but now the bike wont stay ideal it dies after i let the throttle off, what could be wrong and how can i fix it, thanks

 

hmm, not sure actually. You went from a 32:1 to a 40:1 so how does the plug look and was there any elevation changes from the two changes?
Welcome to KF

 

no there wasnt any elevation change at all.

 

ok, that is part of my question answered. what about the other?