Husqvarna 350 build thread

[farminkarman]

Alright gang, sounds like there is enough interest in a thread on building husky 350's and their related plastic-cased variants (Husky 340, 345 and Jred 2150...probably missing one). All of the saws in this family, including the 351, 346 oe & ne, 353; Jred 2149, 2152, and 2153 run the same stroke. The 340 and 345 utilize a 42mm clamshell style cylinder from the factory and the 350 and 2150 utilize a magnesium cylinder "riser" that allow the use of a removeable cylinder like pro-saws use. The earlier 350's came with an open-port 44mm cylinder, and the later 350's came with a 45mm cylinder with removable transfer port caps. The later 350's were known to vibrate the mufflers off and burn holes in the top of the oil tank. In my opinion, the coolest part of these cheaper saws is that you can turn them into a respectable firewood saw with basic mods. And if you want to do a high performance build with a 346xp top end, you can do that too. Later I will update this post with some important part numbers to reference for working on these saws. This thread will probably be somewhat slow to build as I don't have a lot of devoted shop time, be patient.

Relevant part number list:
537251302 - OEM partition and metal clamp upgrade kit
588775502 - 385/390xp Intake clamp
544809801 - 346xp muffler brace
PC2205 - Meteor brand flat-top piston kit
544142908 - OEM 346xp piston & cylinder kit

 

[farminkarman]

The first problem area on these saws that I want to cover is the intake boot clamp. Husky for some reason decided to use an integral plastic clamp which did a good job of failing and causing lean burn downs on many saws in this series as well as the 357xp's and 359's. Here is what the plastic clamp looks like:

You can purchase an upgrade from Husqvarna if you wish which is p/n: 537251302


I prefer to use a utility knife to cut the locking tabs off the existing plastic partition and then use a 390xp intake boot clamp which is p/n: 588775502
Here is what the partition looks like after removing the tabs:


And then with the 390 clamp:


The reason why I prefer this method is that it is cheaper, and much easier to install/tighten the 390 clamp vs. the one that Husqvarna sells.

 

[farminkarman]

The next problem spot I want to address (only applies to saws with the cylinder riser) is the cylinder riser. On every single 350 I have worked on, at least one cylinder riser mounting screw was loose...on one of them, a screw had backed out enough to wear a hole in the top of the gas tank. I also have found that the case mating surface always need to be trued up. If you don't take care of this, there is a good chance your saw is going to have an air leak when you're done putting the saw together. To fix the flatness problem, I take a piece of 150 grit sandpaper and lay it on top of my table saw bed. Applying light pressure, I run the riser over the paper in a circular pattern until the entire sealing surface is making contact with the sandpaper. Here is what a brand new AM riser looks like after three passes on the paper (this is what I find with the OEM ones too):


Here is how it should look when it is flat:



I have always used Dirko for cylinder bases and for sealing these risers to the plastic case. Other sealers like Moto Seal, etc. will work fine too. When re-installing the cylinder riser bolts, I recommend putting blue loctite on the threads to help ensure they stay put. If you are converting a 340 or 345 to run a 350 or 346 top end and are using an aftermarket cylinder riser, make sure you get the correct screws to match the AM riser. The OEM risers use a coarse threaded fastener, and the AM ones use a standard M6 fastener (if buying from Farmertec, just get the screws at the same time you buy the riser).

Edit: I read that later model 350's didn't use the coarse-threaded riser screws, but I haven't ever come across one. All of them have looked like these:

 

[farminkarman]

The last big problem area for these saws is the mufflers rattling themselves loose. On some saws this led to exhaust gases burning a hole in the top of the oil tanks as I mentioned in the first post. This wasn't so much an issue on the earlier 350's with the 44mm bore (less vibration), but definitely was a problem on the later 45mm units. I'm not the inventor of this idea, but I use a 346xp muffler brace (p/n: 544809801) and I remove the flywheel side mounting leg since the plastic cases don't have a screw like the mag cases do. This seems to support the muffler enough to prevent the screws from backing out. Here is a pic from one of the 350 builds I did a couple years ago:

 

[farminkarman]

If you are just interested in getting a 350 back up and running well in a stock configuration, addressing the three issues above should be all you really need. If you would like to improve the performance of your 350, then keep reading.

Basic 350 mods for improved performance:
- Muffler modification with a second outlet, or an enlarged outlet if an AM muffler.
- Ignition timing advance
- Base gasket delete (models with the cylinder riser)
- Swap to a 346xp piston & cylinder

Novice level 350 mods if you have a timing wheel and a grinder....
- same mods as above
- unshround lower transfer entry area
- widen exhaust 65% of bore diameter is safe...you can go wider if you know what you're doing with port shape and bevels.
- raise transfers to reduce blowdown 16-18 degrees (don't need a right-angle tool on cylinders with the removeable caps)
- widen & flatten intake floor....depending on port close timing ATDC, you could lower to 77-78.

Pro-level 350 mods if you can do machine work and port work with an RA grinder (if going through this much work, I suggest using the 346xp top end)
- Cut squish band
- Cut cylinder base
- Widen exhaust
- Raise transfers.... a lot
- Widen intake
- Unshroud lower transfers
- Muffler mod, timing advance, thin carb shafts, 357xp air filter holder & filter

 

[farminkarman]

There are many different ways to do a muffler mod on these and results may vary depending on what other modifications you do along with it. For a stock saw, I usually take a step drill or use a double cut burr in my grinder to open a hole in the muffler that points forward and to the clutch side. I take 1/2" EMT tubing and chuck it in the lathe to remove the galvanizing...you can use whatever method you like to remove the galvanizing...just make sure you remove it before you get out a torch. Once you have the hole in the muffler and the pipe prepped, you can go ahead and braze the pipe in place. This is what a 1/2" EMT outlet looks like:


On a ported 350, I go straight to 1" EMT primarily because I want to help enable the shorter blowdown I use...and because loud is cool right? Here is what a 1" EMT outlet looks like in these mufflers:


I use an oxy-fuel torch and Hobart coated brazing rods (Hobart # 770512)



For paint, I use this stuff:



If you don't have a torch or are not comfortable with brazing, you can always find a way to open up a hole and attach a deflector.

 

[farminkarman]

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[farminkarman]

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[farminkarman]

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[farminkarman]

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[cuinrearview]

Around seven years ago I did a 350 build with no timing changes. I got rid of restriction in the cylinder riser, smoothed all of the sharp edges in the lowers, and widened the intake and exhaust with a 353 flat top piston. This, along with the normal farmer jones mods had it running with an oe 346 doing firewood type bucking. On smaller diameter wood the 346 still out-rpm'd it.

I still haven't put a 346 top end on one. I have two complete 350s in the "builder pile", but the two 44.3 top ends I'm sitting on will probably wind up on something magnesium cased and red. Looking forward to this Greg.

 

[farminkarman]

Around seven years ago I did a 350 build with no timing changes. I got rid of restriction in the cylinder riser, smoothed all of the sharp edges in the lowers, and widened the intake and exhaust with a 353 flat top piston. This, along with the normal farmer jones mods had it running with an oe 346 doing firewood type bucking. On smaller diameter wood the 346 still out-rpm'd it.

I still haven't put a 346 top end on one. I have two complete 350s in the "builder pile", but the two 44.3 top ends I'm sitting on will probably wind up on something magnesium cased and red. Looking forward to this Greg.

There is definitely value in taking some time to modify the stock 350 for a low-buck rig. If you have run a good ported 346xp, you can match or even exceed that performance with a 350/346 hybrid depending on what all you do. I know Kevin has demonstrated his 346's running with and or out-cutting a stock 572xp in 18-20" wood. One of the last 350's I built was for my BIL and I built that one with a Duke's 346 jug. It was 3 seconds quicker through a 24-25" log than his stock 372xp oe. Suffice it to say, the platform is still relevant if you have the parts to build one.

 

[old guy]

Oh, I have a small pile of those, I think only one left with the stock dished piston.
A couple of them are now 346s. Some of these are pretty snappy, I just finished porting one but the weather has kept it out of the wood, I do like these little saws.

 

[Shane¹]

If this clutters up Greg's build thread too much hopefully a mod can delete my post. But all of these builds are kinda his fault after I saw videos of his on here. I ran into issues with the 345-346 I did and he even helped me get it squared away too. So I am following along as we go here but wanted to share some pictures of stuff if anyone happens to use aftermarket seals. I am working on a red one right now. Hard to get in pictures but you can see how loose the bearings are in the cup. This is what I did on the last one and worked like a charm going to do it again

 

[farminkarman]

If this clutters up Greg's build thread too much hopefully a mod can delete my post. But all of these builds are kinda his fault after I saw videos of his on here. I ran into issues with the 345-346 I did and he even helped me get it squared away too. So I am following along as we go here but wanted to share some pictures of stuff if anyone happens to use aftermarket seals. I am working on a red one right now. Hard to get in pictures but you can see how loose the bearings are in the cup. This is what I did on the last one and worked like a charm going to do it again

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I would like this thread to be useful to folks down the road. That being said, I think this is a great addition. I'm sure other folks have experience issues and challenges with this series of saw that I haven't seen yet....kinda like the one you ran into above

 

[EFSM]

I would like this thread to be useful to folks down the road. That being said, I think this is a great addition. I'm sure other folks have experience issues and challenges with this series of saw that I haven't seen yet....kinda like the one you ran into above

How about tank vents falling off? I worked on several earlier this year where the white vent fitting wouldn’t stay in the tank and I came up with what I think is a pretty ingenious solution that I’d be willing to share.

 

[farminkarman]

How about tank vents falling off? I worked on several earlier this year where the white vent fitting wouldn’t stay in the tank and I came up with what I think is a pretty ingenious solution that I’d be willing to share.

You can post up what you found. I do need to touch on tank vent modifications at some point in this thread for saws with the EPA vent and a ported 346 top end.

 

[EFSM]

This is what it looks like when the vent is missing. This is on a saw with a primer (I can’t remember if all the 350’s have primers). The primer line is broken and unhooked from its fitting. Sorry about the sideways picture.



I used a piece of Echo 90018 fuel line and cut a taper on the one end.

Cut a small (less than one inch) section out of an aerosol can straw and insert it inside the hose most of the way to the taper. Then grease the taper well and push it into the tank vent channel. After it is in as far as it will go, push the straw down the hose using a pick. It is the perfect size to securely lock the line in place.

Slide a fitting double barbed fitting onto the small hose, or make sure you cut it long enough to reach up into the carb chamber. I decided to step up to a larger size to make it easier to fit onto an Echo style vent.
Finished product

I feel like this is way better than using a glue to secure the original style vent, although I have done that too.

 

[hacskaroly]

So I am following along as we go here but wanted to share some pictures of stuff if anyone happens to use aftermarket seals.

Sorry, I am not sure if I am picking up what you are putting down...did you make a spacer from an old oil seal to take up the slack between the bearing and the case?

 

[Shane¹]

Sorry, I am not sure if I am picking up what you are putting down...did you make a spacer from an old oil seal to take up the slack between the bearing and the case?

Yup I used a 6203 bearing shield on each side and it takes up the slack. When I built the first one I pushed the bearings out all the way then the crank shifted like 1/8 inch back and fourth and I couldn't figure out why because I didn't have any oem bearings at the time