Chainsaw Repair

I was ask to show this in the chainsaw repair group.

I was ask to show the differences in the poulan 425 415 cylinder 48mm and the 50mm 445 cylinder. Far left 425 and area for air injection, then 415 no air injection. Then 2 445 air injection. These are the last 4 of these I dont have on running saws. Then you can see the cyl numbers on 415 425 show same. Then the different number used on the 50mm 445.

Now on the 54mm have noticed they use the same number as the 52mm ones.

NO air injection 415 475 saws

Thought I had a pic of the air injection with the cover off. But I dont to show. Can see bellow where it comes in off blue AI part up side of cylinder.
See if this old 445 pic shows. I passed on buying this one. But helped new owner out with parts to finish it. Blue tube up along cylinder area. This was done on 425 445 505.