can someone tell me what tool I need to install the flywheel on the crank I pulled it with harmonic balancer puller to replace timing chain and need to press it back on.

 

Did you ever figure it out I have the exact same problem

 

Don't think I have ever done a 250 Yam but on the several dozen bikes from cheapo Chinese to 700 King Quads that I have removed flywheels, all use a taper and key, just like a Briggs Stratton lawnmower and all you do is clean both tapers, shove the flywheel back on with keyway lined up with key, and tighten the holding nut or bolt to keep it there. Some slight problems can occur if the starter clutch has to go on before the flywheel as the flywheel does not always want to enter the one way clutch, turning the starter gear as you shove flywheel on helps a bit. Always torque the flywheel holding nut/bolt correctly, too loose and the flywheel could "turn" on the shaft knocking ignition timing out. Too tight and you can't get the flywheel off again next time.

 

I figured it out the guy that was doing the work on it had that sprocket behind the flywheel on backwards I got it all put back together but now it feels like the starters week it'll turn over a couple times real slow and then get locked up the timing chain is not too loose or too tight starter is good it was running before we did the work trust me this is the last time I have somebody else work on one of my ATVs