Husqvarna 340/345/350 Jonsered 2141/2145/2150 Information

[workshop]

I've got a 340 and a 350 on the shelf. This thread has inspired me to want to do the piston upgrade on the 350 (353 piston) but I have run into a perplexing situation on the 340. My 350 has the separate cylinder from the crankcase. My 340 appears to be a clamshell engine. Is it a 340 or is it really something different? Or did Husqvarna make different models of the 340? I will confess my stupidity here, that's why I depend on you guy's.

 

[moody]

I've got a 340 and a 350 on the shelf. This thread has inspired me to want to do the piston upgrade on the 350 (353 piston) but I have run into a perplexing situation on the 340. My 350 has the separate cylinder from the crankcase. My 340 appears to be a clamshell engine. Is it a 340 or is it really something different? Or did Husqvarna make different models of the 340? I will confess my stupidity here, that's why I depend on you guy's.

You need the 350 riser block to put the pro style top ends. Look at your 350 you'll see bolts underneath and bolts holding the jug on. The riser block is essentially a crank cap. The big bore AM kits usually have it in the kit.

 

[workshop]

Ooohhhh! (light bulb turning on) So the crank cap is like an adaptor of sorts. Really cool. LOTS of possibilities now. Fun times are about to begin.

 

[moody]

Ooohhhh! (light bulb turning on) So the crank cap is like an adaptor of sorts. Really cool. LOTS of possibilities now. Fun times are about to begin.

Oh trust me the possibilities are there. Some take some effort and crafty machine work.

 

[MechanicMatt]

Moddy, you ever put a 028super piston in a 45mm jug? I know I can run a flat top 353 piston, but what about the 028supers domed piston? Thanks

 

[moody]

Moddy, you ever put a 028super piston in a 45mm jug? I know I can run a flat top 353 piston, but what about the 028supers domed piston? Thanks

The wrist pin needs to be the same size and I believe the dome nipple is offset. The 49sp piston is domed and I believe has the sAme wrist pin size. IMHO you're better off with a flat top.

 

[elanjoe]

will the crankcase off a 345 work for a 350, I don't see why not ?

 

[mweba]

will the crankcase off a 345 work for a 350, I don't see why not ?

Yes if you have a spare riser.

 

[elanjoe]

Yes if you have a spare riser.

thank you sir.

 

[moody]

thank you sir.

You will also need the appropriate hardware.

 

[elanjoe]

You will also need the appropriate hardware.

i have a 350 that the muffler melted through the oil resovoir ,so everything will bolt right to the 340 case

 

[moody]

i have a 350 that the muffler melted through the oil resovoir ,so everything will bolt right to the 340 case

Yup the oiler and chain tensioner are the only differences. No big deal there. They'll do just as well.

 

[moody]

Here's an example of a 350 converted to a 346. I ported this saw I'm waiting on a carb and a couple other little things but it runs pretty well.

 

[workshop]

Hey Moody, Is there a general rule of thumb for making ports bigger and raising/lowering ports? I've read where they raise this 2mm or lower that 1mm. It looks like you made the exhaust port both wider and higher/lower. Just trying to figure out how much is good and how much bigger will ruin it. I'm looking at getting a degree wheel and getting comfortable reading it. Do you want to raise the exhaust port? And raise the transfer ports accordingly? Do you lower the intake port to extend the amount of time filling the crankcase? It's confusing for this old brain.

 

[moody]

Hey Moody, Is there a general rule of thumb for making ports bigger and raising/lowering ports? I've read where they raise this 2mm or lower that 1mm. It looks like you made the exhaust port both wider and higher/lower. Just trying to figure out how much is good and how much bigger will ruin it. I'm looking at getting a degree wheel and getting comfortable reading it. Do you want to raise the exhaust port? And raise the transfer ports accordingly? Do you lower the intake port to extend the amount of time filling the crankcase? It's confusing for this old brain.

If you cut your squish the intake will go lower. I didn't lower the exhaust. Doing that will cause free porting and you'll lose a little power. I widened and raised the exhaust port. The transfers will vary depending on what you're looking for example torque/or rpms. I'm not as good or as good at explaining as the builders you see a lot of. Mastermind is pretty good at explaining things.

 

[elanjoe]

does anyone Know if the wiha tool set has the driver to remove the safety torx screws on the transfer caps?

 

[SawTroll]

Yup the oiler and chain tensioner are the only differences. No big deal there. They'll do just as well.

I never notised the chain tensioner is different (never looked really), I guess we all learn as we live!

 

[moody]

does anyone Know if the wiha tool set has the driver to remove the safety torx screws on the transfer caps?

I THINK its a 3mm torx bit

Im not sure so I'd ask mweba.

 

[moody]

Give this a little bump

 

[Homelite410]

I never notised the chain tensioner is different (never looked really), I guess we all learn as we live!

I do believe that the 2141 340 saws had a front mounted tensioner. I also believe that you could swap a side mount tensioner into as well.