346xp rebuild and porting

[farminkarman]

This 346 or showed up in the mail today. The owner wants it warmed up and a switch to a 50cc top end. I know there are plenty of these threads, but I figured why not. First things first, I got the saw stripped down. The piston has a smear visible in the last pic…it wasn’t bad enough for the ring to stick, but it was enough to hinder compression a bit.

 

[farminkarman]

I believe this saw is a 1999 model, so I wanted to do a full rebuild on the bottom end before continuing with the fun part. This is as far as I got tonight. Tomorrow I will get the bottom end cleaned up and put back together.

 

[Kiwioilboiler]

Any idea when OE became NE Greg? I have an MMWS oe 346, but also a clean stock 353 in the postal system...

 

[farminkarman]

Any idea when OE became NE Greg? I have an MMWS oe 346, but also a clean stock 353 in the postal system...

I am not certain when the change happened, but I would guess sometime in the early-mid 2000’s.

 

[farminkarman]

Got the bottom end cleaned up and put back together last night. I heated up the cases to around 200 degrees F and the bearing went right in. As soon as I got the bearings seated, I cooled the bearing pockets down with a damp rag.

 

[farminkarman]

Then the cases went back together with an OEM gasket and my husky crank install tool. The flywheel side seal is OEM as well.

 

[farminkarman]

In anticipation of this saw coming, I went ahead and cut the squish on a new 44.3mm jug a few weeks back. Now that I have the bottom end done, I hung the new piston on the rod so I could get the squish set.

 

[farminkarman]

Got squish to land right on 0.020”. I didn’t really raise the exhaust at all, but I had to raise the uppers quite a bit.

 

[farminkarman]

I had ordered some 3mm burrs to help me get the uppers squared up better, but they got put on back order and I couldn’t wait. Still feel like my porting skills kinda suck…hopefully I learn some tricks along the way.

 

[farminkarman]

Got the saw buttoned up. I added a 357xp/359 carb, filter holder, and filter on this side. Talked the owner into going with a pipe outlet since he said he didn’t need a screened exhaust.

 

[farminkarman]

Was able to fire this thing up this afternoon and do a couple cuts. I added some more fuel on the top end after this video and it got stronger.

 

[cuinrearview]

Sounds nasty. Good stuff.

 

[farminkarman]

Sounds nasty. Good stuff.

I am happy with how it turned out. I built it for torque and it still whacks the rev limiter when you crack the throttle. I think he’s gonna love it. Also, I want to give a shout-out to @Mastermind for helping me source a carb for this thing. Also a thanks to @huskihl for sharing some pointers for the 346 platform. To everyone else who shares their learnings on this forum, I am grateful. You all are a good bunch…even @dall

 

[cuinrearview]

I am happy with how it turned out. I built it for torque and it still whacks the rev limiter when you crack the throttle. I think he’s gonna love it.

I have my first ported 346(red) on order. I can't wait.

 

[farminkarman]

I have my first ported 346(red) on order. I can't wait.

I might have a red one in the works too

 

[Kiwioilboiler]

I have my first ported 346(red) on order. I can't wait.

 

[huskihl]

View attachment 334057

It’s a northern outpost long-term storage thing. You can relate

 

[farminkarman]

Just a quick and final update on this 346xp project. I got permission from my local Stihl dealer to do some test & tune while cutting on his wood pile (semi load of red oak). Once I got the saw good & hot, I found it needed another 1/4 turn open on the high jet. Now the saw blubbers before the rev limiter when cold, but it cleans up as soon as it has a couple good cuts on it...figure this is a good spot until the saw is broken in. Compared to my first cuts in the video, the high jet is now 1/2 turn more open...really happy with how this saw pulls The owner wanted to try some square ground chain, so I squared up two loops of .325 chain with a "play" grind and put them in the box with the saw.

 

[Mastermind]

I had ordered some 3mm burrs to help me get the uppers squared up better, but they got put on back order and I couldn’t wait. Still feel like my porting skills kinda suck…hopefully I learn some tricks along the way.

Look for some small diamond burrs. They can be used to tighten up the corners on those small uppers without chatter.