First off hello everyone I'm a new comer! Question is why or what? I have a 97 scrambler 400 and when i engage the 4x4 my sprocket in the front near my right foot wobbles and pops the chain off,any idea on what part needs fixin now as it was a basket case when I got it but is just about all redone now this happened any help is appreciated.

 

Check center tightener bearings,sprockets for wear. Located just forward of right floorboard. If chain loose,loosen 2 pinch bolts,TURN assy towards rear to tighten chain to about 3/8-1/2". ALSO when you adjust center chain,FRONT will loosen and have to be adjusted! Loosen FRONT assy bolt at bottom,can drive assy back with dull punch to where chain about 3/8' slack in middle. Good luck PS GOOD VIEW