my moto-4 yfm100 champ has stopped shifting. it is stuck in what i think is third gear. the shift shaft is still able to move freely and it return to centre like usual. the quad runs fine other than burning a fair amount of oil but that’s been happening since long before the shifting issue. bump starting is getting old any help would be greatly appreciated.

 

Only way to find out is to remove clutch cover and check the selector mechanism. I don't know the Champ at all, but most manual shift bikes use a lever, moving a ratchet mechanism, that turns a star wheel on the end of the shift drum, and most faults are with this mechanism.