Chainsaw Repair

Last night i continued to tear the saw down. I removed the clutch (wow, it was on tight). I got the flywheel off. Used a 2 jaw puller, put a light load on it, then gently heated with a propane torch.  It popped off in a few seconds.  Flywheel is good. Flywheel key is present.

Then, i removed the oil pump.  DIRTY!  I found a big problem.  The play i was feeling in the crank was between the crank shaft and the inner bearing race.

When rotating the crank shaft with fingers (very smooth, almost no resistance), the inner race DOES NOT MOVE.  The crank spins inside the inner race.  However, i can easily move the inner race around with my fingers, so the bearing has not seized.  There is noticeable play between the crank and the race.

After removing the piston, i can feel a tiny bit of play in the big end bearing. It's very hard to judge this, especially with my limited experience.

So, i assume this means i need a crank shaft. This thing is turning into a money pit.  It's certainly not worth what i paid for it. But, at least i am learning. My wife is actually encouraging me to spend money on this thing to get it right, believe it or not.

I can get (what i think is an OE) crank shaft for around $220 with bearings and seals.  I already have a line on a meteor piston kit as well. 

Are there any other reasonable options for the crank shaft?  I hesitate to look for a used one.  Are aftermarket cranks even worth considering? I see them on Ebay for around $80.  I don't believe that includes bearings and seals, so that saves me around what, $100?

Thoughts?

The only step left is splitting the crank case. I have to build a tool, so that may take some time. I'll post pictures later when i get them uploaded. 

I don't think the china cranks have had good luck. I would probably stick with oem for the crank for that saw.

The top picture is a closeup of the end of the crank that was spinning in the bearing.  If i was confident in the big end bearing, i could probably score this area, and press on a new bearing. 

When i pushed the crank out the opposite side of the case (after splitting), the bearing came out of the case and stayed on the crank.  The case looks good on both sides.  But, man are those bearings tight in the case. I'm wondering how in the world i can press this thing back together.

What is the best method for this? I have seen some people put the bearings on the crank first (easy if you freeze the crank, and heat the bearings).  But, how then would i press the crank into the case half, and then put the two halves together?

Ah, that makes sense. Which case half should i push the crank into first? 

The bearings that came out of the saw had plastic in them.  I assume if the new ones do, i won't be able to heat them.

It turns out that the front AV mount bolt was simply very loose.  I removed, inspected, then tightened it back into the tank, and it seems firm. 

The AV mount on the cylinder has a rounded out threaded hole on the plastic end. So, i'll replace that one.  The rest of them are fine. 

I heated the halves up in the oven when I did a 390 crank. I put the bearings on the crank first with a socket on the inner race with a 1/2 socket. If I remember right you can use the oil pump as a guide for how far to seat it. I seated that side first and then the starter side. Heat the case halves to around 250° for a half hour or a little longer. You could support the case good and use a large socket to drive the bearing out. I think one side stayed in and the other stayed on the crank when I split the case. My case splitter is almost identical to yours.