Husqvarna 450 has zero compression after a new piston and rings

[chainsaw101]

My wife gave me a Husqvarna 450 Rancher for last year's Christmas, but now the rings are stuck, and it only has 30 psi of compression. I swapped in a new piston and rings, but now it has ZERO compression. I've checked for leaks, and I can't find any.
The cylinder looks fine. What am I missing? How did a new piston make it worse?

 

[log5plitter]

Make sure the rings are facing the right way and that the gaps aren't lined up, or you'll have leaks. Also, be sure the piston is facing the correct way and that the cylinder isn't smooth or misshapen.

 

[JJoe_257]

My wife gave me a Husqvarna 450 Rancher for last year's Christmas, but now the rings are stuck, and it only has 30 psi of compression. I swapped in a new piston and rings, but now it has ZERO compression. I've checked for leaks, and I can't find any.
The cylinder looks fine. What am I missing? How did a new piston make it worse?

Same thoughts as @log5plitter, it might be an installation error..
Have you checked the gaps on the new rings?
If the gap is too tight, the rings can bind up and break, which would cause zero compression. It's a quick check with a feeler gauge.
Next would be to make sure the arrow on the new piston points toward the exhaust port.
If it's backward, the ring locating pins won't be in the right spot, and the rings will get caught in a port.
This is a common mistake and would definitely kill your compression.

 

[Odd Rod Todd]

Just a thought: Does the saw have a compression release? Could it be stuck open?