Chainsaw Repair

I was doing a complete tear down and clean up after realizing it was running like crap and I came across this disappointment seen in the picture.

Is this craccked piston normal or a rarity?  One side seems more worn as well. Should I get a new piston or a piston and cylinder.

I also can't take the flywheel off and the casing doesn't want to separate. Does anyone know how to take the wheel off without hammering it. I don't have th e special thread tool and my puller is too wide to fit in the casing.

Stubborn flywheels I have learned to spray both side and let soak in PB Blaster for a night.  On stihls I have the tool for that one homemade by Al Smith and they are like $20 $30 OEM on feebay.

I think the internal threads are M22 by 1.5 which are metric bango fitting size for hydraulic tubing .They made a puller for MoPeds which has both sizes for Stihl .

I think the larger size is M26 for 084s' etc which I can't find in tubing sizes or I'd have made a few of them as well .

You can often thump off a flywheel  with a block of hard wood and a hammer just do so carefully .Don't ever thump on the wheel or the shaft directly with a metal hammer .

I might add on this heat to the bearing pockets on flea bay as of yesterday there was a used Milwaukee industrial heat gun cheap which is what I use to apply heat to a saw engine if needed .They put out something like 1000 degrees .

What I used were hydraulic fittings I found at work .If you have to buy one you're just as well to buy the puller to begin with  as the cost diff if any would be small .You might try flea bay or just Google it .

I took the old wagner paint stripper to it and after heating it up it came off with a wood block. 

I still can't get the casing apart. There is nothing left but the gasket and the thing is still frozen. should I be tapping it and heating it up. I guess the seal is the only thing holding it at this point. I was hoping to remove the flywheel and reveal a screw but no such luck.