395xp porting numbers

[NPKenny]

I’ve got a Husqvarna 395xp torn down to port. It was a good runner but needed a piston to be freshened up.

Current numbers with a Meteor piston and base gasket removed:

Exhaust: 104
Transfers: 119
Intake: 78
Squish: .030

All of the threads with 395xp numbers are for saws with machine work, tighter squish, and higher compression. The numbers all look like 100 / 121 / 83 or so.

Without machine work, where should I go with this saw? 28” bar in normal use with 42” on rare occasion. I prefer torque and crisp throttle response.

Thanks!

 

[drf256]

@Moparmyway

The guy above built mine and it’s a spectacular saw.

I’ve never done one myself. I was gonna but my pal above suprised me with an awesome build.

I’d say raising your exhaust roof to 100 and leaving the rest where they are would work well. You need more Blowdown. I’m actually suprised your transfers are at 119. Did you check with a ring or visually?

I’m going off theory alone.

 

[NPKenny]

I checked visually. It was admittedly difficult to see the transfers in this cylinder compared to others I have done.

 

[huskihl]

Your numbers do seem odd. Check your transfer height with a ring in the bore. Install the cylinder and turn the wheel to 125 or so. Remove the cylinder and check where the bottom of the ring is.

 

[Moparmyway]

 

[NPKenny]

Dang! Thank you, Sir!

 

[Redfin]

That saw is a boss.

 

[NPKenny]

Your numbers do seem odd. Check your transfer height with a ring in the bore. Install the cylinder and turn the wheel to 125 or so. Remove the cylinder and check where the bottom of the ring is.

Improved numbers using the ring method and more careful set-up (honestly this 5* difference in transfer height visual vs ring method has me seriously questioning every previous saw I have ported for myself)...

Exhaust: 105.5
Intake: 77
Transfers: 124

You can see in the pictures that I removed the squish ring also. I’ll probably lose a bit of compression ratio due to combustion chamber volume, but I really disliked the step.

Ring on transfer height



Degree wheel on 124* for transfers




Blowdown through Ex. Port.... 18.5*

 

[mdavlee]

I’d raise exhaust 5-6 and transfer 2 to shape them how I wanted. Check the lower windows to match the piston windows good.

 

[Redfin]

If you go any more than 160* ex I would give it a tad more intake also.

 

[XP_Slinger]

Improved numbers using the ring method and more careful set-up (honestly this 5* difference in transfer height visual vs ring method has me seriously questioning every previous saw I have ported for myself)...
View attachment 160325

Now I’m doubting all my saws too...lol! More work to time with a ring but the accuracy is worth it.

 

[srcarr52]

I don’t add any more intake duration besides what gets added by the machine work. Usually ends up below 79, 158 duration.

 

[mortalitool]

 

[Darryll]

Awesome guys. I was just about to post a similar question and then found this. I'm just curious about porting one of these. I have done no Still or 395 type barrels. They kinda look inefficient in the way they breath through the transfers. Is that a fair comment?
I'm tempted to pull the trigger on one too see what I can get out of it.

 

[Mastermind]

View attachment 160264

Perfect.

 

[NPKenny]

I stepped away from all saw sites for about 4 months and left this thread hanging. I left this 395xp in the exact same spot on the bench as the above pictures for nearly the same period. The hiatus started with the Pinewood Derby and continued with baseball and cattle. The good life has lots of priorities!

I dug into the cylinder today and ported it according to the recommendations above... Great recommendations and many thanks! It turns out it will be a practice jug however. The cylinder scoring above the flywheel side transfers wouldn’t clean-up. It wasn’t aluminum transfer on this one and I should have inspected it more thoroughly before diving into the port work.

Notice where I worked through the Nikasil just left of the decomp hole and still couldn’t get the scoring to clear-up.




Here are the pictures of the port work... Please share critique for the good of the community and my improvement for the next 395xp cylinder I get my hands on.
Exhaust - 101*
Transfers - 121*
Intake - 81*
Squish .029”

Exhaust - about as wide as I could go .



Intake - widened and flattened the floor


Uppers and Lowers



I’m really most interested in the approach on the upper and lower transfers. My strategy was to unshroud the lowers and aim the uppers toward the intake. I’m not proud of the work on these. I was getting a ton of Nikasil chipping on the edges.

Now off to find a cylinder.

 

[drf256]

I like your work. Looks good.

Try to buy a new oem P&C set. You’d be surprised and the price.

 

[Dub11]

$150

https://www.ebay.com/itm/HUSQVARNA-...:Q8oAAOSwPzhaIv6k:sc:USPSPriority!66611!US!-1

 

[Mastermind]

Your work looks damn good.

 

[srcarr52]

I'd throw a piston in that jug and run it for R&D. It might eat rings a little faster and be slightly low on compression but you'll still get to make some adjustments and know exactly where you want the new one to be. It will only cost you a piston, meteor is good option or you can go with the cheaper Hyway from CCC, but you may want to grab caber rings for it.