346xp porting

[2broke2ride]

I'm rebuilding this saw for a friend and I'm planning to do some minor port work. I'm totally new to this and my friend understands and is ok with it.
I am planning to just clean up the intake andnexhaist without changing the port shapes. I'm not going to mess with upper transfers either because I lack tools to get in there and I'm nervous about messing up the cylinder liner. I am going to case match the lower transfers and knife edge the divider. I am also planning to delete the base gasket if squish allows and mod the muffler.
Does all of this sound reasonable? Last thing I want to do is end up with a doorstop.

 

[cuinrearview]

Less is more. A base gasket delete and muffler mod(even just opening the stock outlet) goes a real long way on those. Some thoughtful smoothing and widening will help it run better as well. IMO "knife edging" the divider in the lowers is unnecessary, but I have only ran saws that I've not done that to. Good luck and have fun!

 

[2broke2ride]

Muffler mod is already done, just need paint.

 

[2broke2ride]

So should I case match the transfer ports? Or not go that far? They are considerably smaller in the cylinder than the reliefs in the case.

 

[cuinrearview]

So should I case match the transfer ports? Or not go that far? They are considerably smaller in the cylinder than the reliefs in the case.

That's what I've done.
https://www.arboristsite.com/community/threads/building-a-rare-one.330162/

 

[Backyard Lumberjack]

Less is more. A base gasket delete and muffler mod(even just opening the stock outlet) goes a real long way on those. Some thoughtful smoothing and widening will help it run better as well. IMO "knife edging" the divider in the lowers is unnecessary, but I have only ran saws that I've not done that to. Good luck and have fun!

hello - based upon your initial post, if that was my saw... and if I was you... ... I am not, of course... lol... [u-no porting experience, no porting tools, etc] I would pay close attention to what cuinrearview said, advises.

you will effectively raise the compression a skosh, change some of the port timing a tweek, and per ur muf mod ... improve some of the breathing, noise aside! some light and gentle deflashing and ridge blending will help, too.

good job on the braising! to all that, given your stated purpose if it was my project... I would encourage your friend to keep a good sharp chain and run ethanol free mixed fuel. and also use a top grade oil if mixing at home, such as Stihl sells. and set the carb so it 2-cycles under load.

good luck with your project. I like anything modified!

 

[Huskitoter]

Another good 346 porting thread. You don't have to go as far as mm does.

https://www.arboristsite.com/community/threads/mastermind-revisits-the-346xp.230531/

 

[Huskybill]

I did this to my ports on my 262xp. Done with a Dremel with 1/8” shank carbide burrs, drum sanders, polishing compound, then simi chrome polish on the last pass. These pics are just roughing it and raising the exhaust port and lowering the intake port. The piston skirt hangs in the intake port when it’s in tdc. So the piston skirt will be cut in the a upside down u shape to match the port.

I open up the exhaust port on the inside funneling it from the inside(widening it) to match the gasket on the muffler side.

I use a white paper towel to light up the Ported area better.

I can’t wait to port one of my 346xp’s I can to wonders with the transfer ports, remember the faster the exhaust gets drawn out the quicker the intake charges the cylinder. It’s all about smoothing out, making the ports larger, so a better flow happens. Knife edge those ribs in the transfers. Follow the cutting down into the transfer ports tapering it down deep into the port.
Don’t just angle the top edge taper it into the port as far as you can go.

Checkout the pro guys on YouTube who port two strokes the open up the transfers and knife edge the ribs in the transfer ports. I been porting two stroke dirtbikes this wat for many decades. Now scale it down for chainsaws. Trust me it breathes better,



Listen to the Ported saws here and compare them. The ones that are Ported correctly sound different.

I right now only port oem husky cylinders. I heard about the chrome chipping on the am cylinders. I’m not sure how true that it. Someday I’ll test that.

 

[drf255]

That’s not a 262XP cylinder ^^^

 

[cuinrearview]

That’s not a 262XP cylinder ^^^

People say "you can't make this **** up", but apparently you can

 

[huskihl]

Chainsaws aren't dirtbikes and 4wheelers, either. Theres a lot more real estate inside a 250cc case and also a lot more stroke. Saws are also made with small cases and case capacity to keep them lightweight. Sooner or later you can go too far by removing too much

 

[blsnelling]

If an OEM cylinder, I wouldn't touch the ports unless changing port shapes and/or timing. It's simply not need and I see nothing to gain.