I know this has been discussed before but what is the difference between the 394 and 395 piston. I'm building a 394 and have a new Meteor 395 piston here. Everything measures the same so what am I missing?
394XP PISTON
- Thread starter ELECT6845
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komatsuvarna
Arboristsite MVP
I know the 394 uses thick rings and the 395 uses thinner rings. Not sure on the ring end placement or skirt width but I think they're close. Pins bearings and deck height will be the same.
Thickness of the rings are the same on both pistons. The ring ends on the 395 piston are close to center and the 394 are out by the skirts. Would running the 395 piston cause the ring ends to drop into the intake port?
komatsuvarna
Arboristsite MVP
I've never done it so I cant say for sure. One way to tell is to mount the cylinder and look through the intake port to see. Unless the top of the intake port on the 394 is higher than the 395, I'd think it would be fine
OEM 394 pistons use 56x1.5mm rings. OEM 395 use 56mmx 1.2 rings.
OEM 394 pistons use 56x1.5mm rings. OEM 395 use 56mmx 1.2 rings.
Well I just checked that. Rings don't drop into the intake.
komatsuvarna
Arboristsite MVP
you should be good then 
I don't see a problem installing it. Off to get the cylinder cut and a pop-up turned on the piston. If someone knows of a problem doing this please let me know otherwise I'm going to run it.
decableguy2000
ArboristSite Guru
I'm interested in the results as well, as need a piston for a 394 also.
Jeremy
Jeremy
The early 394 used 1.5mm thick rings and were pinned much in the same manner as a Stihl 460 piston- out by the skirt edges. Later 394s used 1.5mm thick rings and were pinned in the center, same as 395. The first 395s that came out used this same piston so you'll see some 395s with a piston using 1.5mm thick rings. Later, the 395 was switched over to the 1.2mm thick rings still pinned in the center.
The Meteor 395 piston works perfectly in a 394. I've put many of those together. I've even used the Meteor 395 piston in a Jonsered 2094.
Thanks for the info
Mastermind
Work Saw Specialist
I regularly use the 395 piston in the 394. The pin placement is better for widening the upper transfers.
I'm glad you guys replied. I just had the cylinder base cut and a pop-up on the piston. My confidence about putting it back together is better now.
Mastermind
Work Saw Specialist
The best piston IMHO to use in either a 394 or a 395 is a Meteor 395 slug. A little wider skirt, and excellent pin placement.
I appreciated the info guys, here are some pictures of the saw. I think it turned out good for what I started with and yes it runs very well. 
Lookin' good there bro!
Thanks Brad. It can be a challenge to get the port shape's right and make it look professional. I'm getting better but still got along way to go. Hopefully one day I can make them look as good as you professionals.
srcarr52
We can't stop here, this is bat country.
The 395 piston is a little bit shorter on the skirt length thus giving the saw more intake timing without touching the ports. The crown height is the same. Ring pin locations are better and the rings are 1.2mm instead of 1.5mm as described in previous posts. OEM 395 pistons have little wingdings that come off the pin boss bridge and contact the cylinder bore that can limit the lower transfer flow but Meteor AM pistons do not. Weight wise the 395 is slightly lighter due to the shorter piston skirt, at least with the AM Meteor pistons.
Nice Elasto-Start! The best part on that saw...
The old rope only lasted about 3 pulls. Lots of compression and a old rope equals a new Elasto-start.
It depends on where you're getting your Meteor pistons. All the Meteor 395 pistons I've bought have the "wingdings" on them, same as OEM. Skirt length has been the same as well.
