346 porting

[khaas]

Was given a 353 to me by a friend that had a cylinder. No interest in saving the old one. There is a highway 45 mm kit on eBay I plan to buy. Going to delete the base gasket as well as put a 288 muffler on it. Right on here somewhere that a prior user head shaved a couple millimeters off the exhaust Port sides and a millimeter or two off the intake as well. Anything else worthwhile? Would it be worth it to advance the ignition a little bit?

 

[Bob Hedgecutter]

What advantage is the 288 muffler addition?
Assuming (I have not tried it but can attempt) it actually fits in without contacting the top cover and or case.

 

[khaas]

What advantage is the 288 muffler addition?
Assuming (I have not tried it but can attempt) it actually fits in without contacting the top cover and or case.

The 346 and 353 have an internal pipe that terminates inside the chamber. Not really a possibility of a straight-through design. The 288 will have a straight through exhaust setup

 

[Bob Hedgecutter]

The 346 and 353 have an internal pipe that terminates inside the chamber. Not really a possibility of a straight-through design. The 288 will have a straight through exhaust setup

Oh- okay.
Make sure to take plenty of photos.

 

[khaas]

Oh- okay.
Make sure to take plenty of photos.

Since you're interested here it is. Not easy to tell with the pictures but I'll try to explain it as best as possible. Once the exhaust leaves a cylinder and goes into the muffler there are two chambers. The chamber farthest from the cylinder must be accessed by the exhaust gases through various holes in the wall. After the exhaust goes through the wall it enters the tube which then travels up and out the top of the exhaust. You can kind of see the tube on the left side of the muffler inside

 

[khaas]

Easy way to tell the 353 open port cylinder from a 346 closed Port cylinder is the 353 has these access panels bolted to the side

 

[Bob Hedgecutter]

Yes, fairly familiar with all the internals of the mufflers concerned- own all the saws you are talking about.

 

[khaas]

Notice daylight coming through the exhaust outlet and this aftermarket 288 muffler. Straight through

 

[Bob Hedgecutter]

Easy way to tell the 353 open port cylinder from a 346 closed Port cylinder is the 353 has these access panels bolted to the sideView attachment 1140606

The last of the plastic cases purge valve equipped 350's also run the same cylinder.

 

[Bob Hedgecutter]

Notice daylight coming through the exhaust outlet and this aftermarket 288 muffler. Straight throughView attachment 1140607

So you have the 288 knock off muffler in hand?
Can compare the two for overall physical size?

 

[khaas]

So you have the 288 knock off muffler in hand?
Can compare the two for overall physical size?

Nope not yet. I read on here it's a replacement for the 346 though. I'll update when I get it probably be a couple weeks

 

[Bob Hedgecutter]

Nope not yet. I read on here it's a replacement for the 346 though. I'll update when I get it probably be a couple weeks

Read it on here- must be true then.
Will be most interesting to see how you make it work.

 

[bwalker]

The 346 and 353 have an internal pipe that terminates inside the chamber. Not really a possibility of a straight-through design. The 288 will have a straight through exhaust setup

I dont think the 288xp muffler will work. The holes on the 346 are stagged and the 288 are not. However, the 288 muffler deflector is often used when muffler modding.
Every 346xp I have had has a hollow muffler with a top outlet. The 353's often have CAT mufflers that are plugged up.

 

[Chevboy0167]

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[Bob Hedgecutter]

I dont think the 288xp muffler will work. The holes on the 346 are stagged and the 288 are not. However, the 288 muffler deflector is often used when muffler modding.
Every 346xp I have had has a hollow muffler with a top outlet. The 353's often have CAT mufflers that are plugged up.

Party pooper- I was waiting for the DAMMIT posts in a couple of weeks.
And yes- I am pretty sure the 288 deflector use is where the confusion is entering and there are MANY options for a straight through 346 type mufflers in the same kind of knock off aftermarket avenues the 288 one was coming from.

 

[khaas]

I dont think the 288xp muffler will work. The holes on the 346 are stagged and the 288 are not. However, the 288 muffler deflector is often used when muffler modding.
Every 346xp I have had has a hollow muffler with a top outlet. The 353's often have CAT mufflers that are plugged up.

I think you're right I may have been mistaken I think it's just the deflector that's used

 

[huskihl]

The only 346 style muffler that isn’t mostly hollow is the 2152c or late 353 Etec. And the 353 cylinder pic you posted is actually closed port. It’s the earlier 350/351 cylinder that was open port.

The Hiway 45mm cylinder won’t make any more power than the one you have. I’d save up $10 more and buy an oem 44.3mm 346 cylinder