Hello OPT!


I recently received a 1996 300 Xpress from an Uncle. The oil lines clogged and ruined the piston. Until that recent event it ran fine. I have the top end off and at the machine shop but I noticed I can move the crank shaft on the flywheel side ever so slightly up and down. I don't have a dial indicator to actually measure the play but it is definitely more than my 1992 250. It has none whatsoever. Do you think I should split it and have the crank rebuilt or does that sound normal?

 

Yes remove the crank! There should be NO up and down play from the rod or crank bearings.It would just be more trouble a little later and could damage the new top end if it spits pieces out. Plus don't forget new crank seals.Plus if you use the pump make sure you bleed it and premix the first tank of fuel 50-1. 40-1 if you bypass the oil pump.

 

Somehow I was afraid you were going to say that lol .Yeah I actually pulled the flywheel to make way for the new seal when I caught that issue. Anything I need to be aware of splitting the case? I have never gone that far into one of these. Looks like the service manual says I will need to heat around the bearing support areas tap apart. Anything tricky or special tools needed?

 

No special tools needed. Yes heat around the bearing supports and tap around the case at several points. You can even give the pto(clutch side) crank shaft a good whack with a dead blow hammer to help in this process. When you get the crank shaft back,have both bearings on the clutch side crank shaft,heat the case up and just drop the crank in place. Let it cool off,apply Three Bond or Yamabond around this case half while you're heating up around the other case half bearing support,then just tap the case half on the other one. Gloves are highly recommended!

 

Got it apart last night without issue and will follow these steps putting it back together! Appreciate your wisdom very much! James