Stihl 045 what dia. piston

[HarleyScooter]

I am stuck in the middle again? A friend needed a piston he told me he has an 045 AV I looked it up and it showed a 50mm piston. I asked here about getting one and I was linked to e-bay, I found one there at Best Chainsaw Pistons, my friend doesn't have a e-bay account so he asked me to buy it for him, but by mistake they sent a 52mm piston. Now I called my friend who was in his garage at the time and he says the saw reads 045 AV Super Electronic, when I looked up a 045 AVSE (if that means super electronic) and that shows a 54mm piston. The seller on e-bay seems really good 1500 feedbacks at 100%, but I really don't know what I need now. I e-mailed the e-bay seller but I wanted to ask the pros here also. The saw is not apart now and he doesn't want to take it apart until he can put it right back together (old timers? I'm getting it too) so I can't mic the piston. I really need to stop getting in the middle of things?
Thanks
Scott

 

[Big feller]

Unless you know the history of the saw, the only certain way to tell is to measure the piston - a ruler will do fine.

The problem is that 50, 52 and 54mm cylinder and piston combination will all fit on the case and thirty years on it is quite possibly not running what left the factory. If a previous owner got a good deal on a different size then any of the three are possible. That said, 50mm was only used on early 045s and is very unlikely.

My AV Super electronic has a 52mm setup. I haven't had it from new but I'm pretty sure it is original. If the 52 doesn't fit your friend's then it's pretty certain it will be 54mm.

 

[Lakeside53]

Take the muffler off and measure the cylinder bore though the exhaust port.

 

[HarleyScooter]

Thanks guy's I never thought about going through the exhaust great idea. It looks like one way or another we will have to get into it to find out for sure.
Thanks again
Scott

 

[HarleyScooter]

Just a follow up after mic'ing the piston we found out it is 54MM, the e-bay seller Best Chainsaw Pistons is a good guy and he is sending me a 54mm piston for a 056. If you need one of these old saw pistons check his e-bay store out. $32.99 + shipping for the kit. Thanks again for all the help.
Scott