Husqvarna 346xp and 353 cylinders

[Turner Saw]

I recently picked up a couple 346xp's. One is the OE and the other is what I thought was a NE model. Silver clutch cover and all. The NE model has removable covers on the transfers. The tag on the crankcase is 346xp. Does this saw have what appears to be a 353 cylinder on it? The top is marked 45L. It runs really good by the way.

 

[PA Dan]

I recently picked up a couple 346xp's. One is the OE and the other is what I thought was a NE model. Silver clutch cover and all. The NE model has removable covers on the transfers. The tag on the crankcase is 346xp. Does this saw have what appears to be a 353 cylinder on it? The top is marked 45L. It runs really good by the way.

Sure does sound like it!

 

[Turner Saw]

Sure does sound like it!

I'm not familiar with the 353 at all. Is the piston/cylinder combination decent?

 

[dustinwilt68]

Decent yes, a 346 NO. 346 was the full pro version and had better power, 353 was semi pro and ran very well.

 

[Turner Saw]

Decent yes, a 346 NO. 346 was the full pro version and had better power, 353 was semi pro and ran very well.

Yeah. I'm just getting into the 346xp builds right now. I build mainly 70cc plus saws 372's ms460's etc. but wanted to build a couple of these. I've got a few things to learn about them I guess. I bought it online and didn't see the cylinder until it arrived.

 

[huskyboy]

Hopefully they didn’t put a 350 “dished” low compression piston in it. Later 350’s share the same cylinder as a 353, but utilized that piston to detune the saw. A 346NE cylinder does run better despite the minor displacement disadvantage. The transfer ports are a better design.

 

[cuinrearview]

346OE=42mm
346NE=44.3mm
350OE/351=44mm
350NE/353=45mm

 

[Turner Saw]

Update on this post. I took the 353 cylinder off the 346xp and ported an OEM 346xp cylinder, now that's it back to a true 346xp it runs great. I had the 353 cylinder on the bench and for the heck of it I ported it and put a flat top piston in it, put it on a 350 chassis. I milled the riser and did a muffler mod. I was really surprised how well this thing runs! Lightweight and good power.

 

[PA Dan]

Update on this post. I took the 353 cylinder off the 346xp and ported an OEM 346xp cylinder, now that's it back to a true 346xp it runs great. I had the 353 cylinder on the bench and for the heck of it I ported it and put a flat top piston in it, put it on a 350 chassis. I milled the riser and did a muffler mod. I was really surprised how well this thing runs! Lightweight and good power.

Awesome! I will be doing the exact same with a 353 and 350 this winter!

 

[old guy]

Update on this post. I took the 353 cylinder off the 346xp and ported an OEM 346xp cylinder, now that's it back to a true 346xp it runs great. I had the 353 cylinder on the bench and for the heck of it I ported it and put a flat top piston in it, put it on a 350 chassis. I milled the riser and did a muffler mod. I was really surprised how well this thing runs! Lightweight and good power.

Yep,I've ported 2 or three 350s, milled the riser and put the hyway popup piston in them & they are rite up there in 346 country.

 

[PA Dan]

Yep,I've ported 2 or three 350s, milled the riser and put the hyway popup piston in them & they are rite up there in 346 country.

How much are you milling off the riser?

 

[cuinrearview]

How much are you milling off the riser?

Both that I've done took .010 to put them right about at .020 squeesh. The last one that I did I went wild opening up the lowers, so much that i had to JB the covers back on as i cut through the cap gasket. I raised the uppers very slightly and hogged the "tunnels" some too. It really runs nice. I still haven't timed it but I might try this weekend. Some more compression buy way of cutting the base and band could be in it's future.

 

[old guy]

How much are you milling off the riser?

Measure the squish with base gasket, mill enough off the riser to leave .020 squish.

 

[old guy]

I'm getting 184 lbs. comp with the popup piston, that's using a base gasket.

 

[PA Dan]

Measure the squish with base gasket, mill enough off the riser to leave .020 squish.

Yep will do was just wondering...

 

[old guy]

I also fill in that deep corner in the riser with jbweld, I think it hinders a smooth flow of fuel.
Put the cyl. on the riser & look at it from the bottom, you'll see what I mean.

 

[Turner Saw]

I opened up the lowers and cut back the cap bolt hole bosses. They create kind of a choke point. I raised and redirected the uppers more towards the intake. I ended up at 155 degrees on the intake. 120 degrees on the transfers and 168 degrees on the exhaust. I also tapered the top of the riser leading into the lowers and milled off the small divider that was there for the original open port cylinder.