Husqvarna 340 - mod or sell?

[Ryan'smilling]

This is awesome! This will absolutely help. Just to clarify, all this is applicable to the 340 as well - true? Also, what exactly is squish?

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True. Squish is the amount of clearance between the top of the piston and the cylinder at top dead center. You can check it with some soft solder that's just a little bigger than the actual squish number.

 

[Mattyo]

To the op...check my sig. My youtube channel has full teardown and rebuilds of the husky 350 ....mods and all. More info than you could ever want. I also have a full teardown of Brads 340 346xp which was probably the most powerful in this class that I've run. It's all there on my channel.


Nice pics by spyder though

 

[spyder62]

Glad you like the pics! And yes, this will work on your 340. Here’s a few more pictures. The one on the left is from a 345 and is basically what your 340 has. The one on the right is original to this saw (350) notice the length difference, this is why you need the bearing cup. I also included pics of the original piston and bearings. Piston was scored on the intake side and one of the bearings is missing the retainer

 

[sunfish]

Well now I want to build one of these plastic bottom saws, even though I have a bunch of 346s'.
Thanks a lot guys!

 

[svk]

Join the dark side @sunfish

 

[spyder62]

Looks and sounds healthy, svk. Did you port it?

 

[svk]

Carl did. That's an OE 45 cc top end

 

[Mattyo]

I'm not even sure anyone can tell the diff in power from the 346 to the 350 with a similar head on it. Just depends on whether you like the plastic case or the metal. plusses and minuses to both

 

[sunfish]

I like the metal cases better, but the plastic ones seem to hold up just fine.

 

[svk]

If a guy can find a reasonably priced 346/351/353 then by all means I'd definitely build that. When I was looking for a 346, they were all listed at well over $300 for anything that wasn't totally roached out. Not counting porting of course, you can buy a clean 340/345/350, factory 346 top end, new seals, and bearing cap (if needed) and have a saw that's virtually new for under $300. Yes it won't hold resale like a 346 but for many folks that doesn't matter.

 

[spyder62]

Right before Xmas I found a rough looking but running oe 346 for a hundred bucks. That’s what I bought this p&c for. I took it apart and the cylinder looked fine except for a cracked fin. Just fooling around I put a used 345 piston and ring in it. Gasket delete and opened up the muffler. Man that thing rips. The last time I ordered parts I got a new ring for it but haven’t put it in. Really no reason to, not yet anyway. It’s 5cc smaller than the ne but there’s just something about it I love.. I’d love to find a 351 or 353 there tough to find and kinda pricey when you do see them.

 

[Scandy14]

The 340/345/350 is a good platform to work from. Lot it potential in these saws.


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[Mpl127]

Guys- just bought a 340 of eBay f0r $70. Not running. Seller thought it needed a carb tuning and work to the starter. Not counting on this as to the extent of repairs needed. Haven’t received it yet but should next week, looking to get a head start on ordering parts for this conversion, looks like a pretty comprehensive parts list from the posts above. In reading at all of these threads on this conversion, i have some questions.

1. Stock 340 carb and stock 346 carb can be used with all new parts ordered from above? It appears so but just want to make sure.

2. no factory gaskets to be used between bearing cup and cylinder or bearing cup and crank- yamabond or equivalent high quality sealer between both? Said yamabond because that’s what i have a tube of, if there is something better please let me know.

3. I’m assuming the above set up has an impulse path?

4. Crank seals- this saw looks to be 90s, but dont have the SN yet, should i just replace as I’m doing this? Not touch, seal and bolt everything and pressure/vac test? Looking at pictures above, Do they (crank seal) simply seal by tight tolerance machining or do they need sealer applied as well? noticed some ribs on them.

5. The muffler- opening it? The vaguest response that makes sense please.

6. part numbers for changing to adjustable oiler?

Thank you.

 

[Mpl127]

B

 

[svk]

1. Stock 340 carb and stock 346 carb can be used with all new parts ordered from above? It appears so but just want to make sure. Yes any of the carbs will work from this family. Some may say one carb works better than another but I do not know. My 345 converted to ported 346 OE with a stock 345 carb was an absolute screamer until it ingested something.

2. no factory gaskets to be used between bearing cup and cylinder or bearing cup and crank- yamabond or equivalent high quality sealer between both? Said yamabond because that’s what i have a tube of, if there is something better please let me know. Yes, should be fine. Be sure you do not goop over the impulse hole (I haven't had one apart in some time so not sure exactly where it is.)

3. I’m assuming the above set up has an impulse path? Yes

4. Crank seals- this saw looks to be 90s, but dont have the SN yet, should i just replace as I’m doing this? Not touch, seal and bolt everything and pressure/vac test? Looking at pictures above, Do they (crank seal) simply seal by tight tolerance machining or do they need sealer applied as well? noticed some ribs on them. Definitely replace the crank seals. They are cheap and easy to do.

5. The muffler- opening it? The vaguest response that makes sense please. It will run much better with a muffler mod and timing advance. Lots of threads on here of various muffler mods. The cheapest way is to "swiss cheese" the front of the muffler but looks kind of redneck. Or you could weld/braze in a new outlet and widen the existing one. Please note that several small holes will flow just as well as one large one, and the saw will be quieter and way less "crackly".

6. part numbers for changing to adjustable oiler? Not sure but I am sure they have them on Ebay.

Answered in order to the best of my recollection

 

[Mattyo]

Just did a 346 350 live on YouTube. Lots of extras and fiddly stuff. Id recommend check out the 359 carb el42 from jacks small engines. They have the best deal. But a 350 carb works fine.

New crank bearing and seals are not cheap but worth it. Sometimes a trick to install too....as you'll see in the video.

Use 1184 for base sealer.

 

[Mpl127]

I’ll dial up that video mattyo, I’ve watched many of your other ones, didn’t know it was out there. The timing adjustment scares me a bit. I do have a dentist buddy who is going to give me some his retired tools as they become available. What is the name for the dental grinder you use, so I can request it?

 

[Mattyo]

You don't need a timing advance on this saw. I use a e type lab handpiece ...marathon 3 clone. Straight nosecone and latch right angle.

 

[czyhorse]

FWIW, I agree with deaves61. I’d do what he says but also do a gasket delete and open up the muffler. You’ll be adding 10cc to the saw , compression will be much higher and I’m sure the 346 top end will flow much better. You already have a good start with what you have.

What is a gasket delete?

 

[Mattyo]

Usually the cylinder sits on a gasket...removing this gasket (and replacing it with just sealer) tightens the distance between the top of the piston and the cylinder at top dead center increasing compression. Sometimes there is room to do this ...sometimes not. Gotta be careful