husky 350 port timing

[mathewsdxt75]

So this is my fisrt go at checking port timing, then possibly doing some port work to my saw.
First off, this is a 44mm p/c with open transfers. All stock, this is the first time it's been apart since I bought it nearly 15 years ago.
I am curious if these numbers look to be correct for a stock husqvarna.

Squish is .042 (my plan is to remove base gasket to get closer to .025
Exhaust--- 152 deg.
intake------120 deg.
transfer----140 deg.
I already did a muffler mod, and that helped.
I've been searching threads looking for numbers but really couldn't find much. Idk, mabey I need to look harder.
If indeed these numbers are "normal" for stock, I am looking/asking for suggestions to point me where I could get the numbers to for a mild port job. Just enough to wake it up.
any advice is most appreciated

 

[old-cat]

Increased compression does more to wake saws up than anything else.

 

[mathewsdxt75]

Increased compression does more to wake saws up than anything else.

That is good to know, thanks. Thats the main reason for wanting to remove the base gasket. I just checked squish without the gasket, I have .023. That is good enough for me.

 

[Mattyo]

you've posted durations for timing numbers...not degrees. just fyi.
check exhaust opening... mastermind has a general rule that these small saws should have an exhaust opening of 105 or so... so if you are aiming for a blowdown of 20 ...then the transfers should open at 125 or so. I aim for an intake opening timing of 78-80 degrees before TDC.... i've only done a few so ... i'm no expert on this. I have one saw with an aftermarket P&C that has a compression at 175 ... it really rips. I don't even know the timing numbers on it, but after bringing the squish down to 020 and one tank of breakin ... its got pop.

Not sure what the ultimate capability is on a 44mm open port.

 

[mathewsdxt75]

you've posted durations for timing numbers...not degrees. just fyi.
check exhaust opening... mastermind has a general rule that these small saws should have an exhaust opening of 105 or so... so if you are aiming for a blowdown of 20 ...then the transfers should open at 125 or so. I aim for an intake opening timing of 78-80 degrees before TDC.... i've only done a few so ... i'm no expert on this. I have one saw with an aftermarket P&C that has a compression at 175 ... it really rips. I don't even know the timing numbers on it, but after bringing the squish down to 020 and one tank of breakin ... its got pop.

Not sure what the ultimate capability is on a 44mm open port.

Good point. My bad.
exhaust is 104
Transfer is 120
Intake is 72

 

[Mattyo]

the blowdown seems tight ...16 degrees?, and I think you can open up the intake more... only thing I'd do personally if I had that setup would be to touch the intake... if the compression is high then maybe you can raise the exhaust a touch...

one thing I haven't seen, is a discussion of what blowdown really does... like what happens at the extremes, say a blowdown of 10 vs a blowdown of 40 ... maybe oldcat or someone else can point me in the right direction there and we can both learn something.

 

[rdtreewalker]

Increased compression does more to wake saws up than anything else.

I know where there's a 268xp that lost 15 lbs of compression and its a pile faster than it was stock.

 

[mathewsdxt75]

the blowdown seems tight ...16 degrees?, and I think you can open up the intake more... only thing I'd do personally if I had that setup would be to touch the intake... if the compression is high then maybe you can raise the exhaust a touch...

one thing I haven't seen, is a discussion of what blowdown really does... like what happens at the extremes, say a blowdown of 10 vs a blowdown of 40 ... maybe oldcat or someone else can point me in the right direction there and we can both learn something.

I am also curious of what different blowdown numbers do for the performance of the engine. Is it an rpm thing or a torque thing. Idk.
I will have plenty of time tomorrow seeing as it is -12 right now and still falling.

 

[mathewsdxt75]

I just finished up porting and cleaning up my 350. I didn't go crazy on it. Just what I am comfortable with doing. I opened upthe exhaust port some, took out the a "hump" in the intake port. I matched up the transfers Between the two halves for better flow.
So I cleaned everything in preparation for reassembling. I was just about to start and found a torn crank seal on the clutch side. I guess the timing was darn good to go inside this saw before damage was done
I have read two different things, the seals come with bearings, and the seals can be replaced separate.
One more thing, is it a good idea to put a new piston ring in. Saw ran good, it had 135 psi.

 

[Mattyo]

With 023 squish I would expect better compression. ..it'll run with 135....but there's quite a bit more pop around 160 180

 

[mathewsdxt75]

With 023 squish I would expect better compression. ..it'll run with 135....but there's quite a bit more pop around 160 180

The compression was with the gasket at .043 squish.

 

[Mattyo]

New rings r cheap. ...toss one in

I bought a bunch from the Greek guy on ebay...cabers

 

[mathewsdxt75]

I will probably have to order seals and bearings anyway because my local husky dealer doesn't stock hardly any parts. They have one box of parts
I will get a ring while I'm at it.

 

[mathewsdxt75]

The numbers on my saw
967 01 13-00
00 4903208

Am I correct that this saw was built in 2000??