Adding Some Sauce To Echo 355t

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

SierraMtns

ArboristSite Operative
Joined
Mar 22, 2017
Messages
356
Reaction score
307
Location
Shingle Sprins
Ran a couple tanks through the saw and it ran good but I think there is more in this saw. So to the bench we go. Surprised at the compression. Tear down and clean up. My plan is to change the bottom transfers a little, raise the intake a touch, and widen the exhaust. Nothing too crazy, just wake the saw up a little more.


Next is porting timing numbers. I might need your guys help with figuring out the numbers. I am no pro tuner. Just do this for fun on my own saws.

IMG_9235.JPG IMG_9262.JPG
 
Started getting numbers.

*Intake*
Intake opened at 70.5* and intake duration is 219*.

*Upper Transfers*
Starts opening 126.5* ATDC

*Exhaust*
Starts opening at 68* ATDC

What do you guys think? Do these numbers seem right?
 
Started getting numbers.

*Intake*
Intake opened at 70.5* and intake duration is 219*.

*Upper Transfers*
Starts opening 126.5* ATDC

*Exhaust*
Starts opening at 68* ATDC

What do you guys think? Do these numbers seem right?
I think your intake opening is correct at 70.5. But duration would be 141

Your transfer opening is right

Your exhaust opening is probably 112. Guessing you read your wheel at degrees after bdc

All just a guess lol
 
I think your intake opening is correct at 70.5. But duration would be 141

Your transfer opening is right

Your exhaust opening is probably 112. Guessing you read your wheel at degrees after bdc

All just a guess lol


Cool thanks Kevin for the help. I cant seem to figure out which side of the wheel to read when I get to a port. :confused: BDC or TDC
 
IMG_9432.JPG

Laying out the grind lines last night. I am still trying to figure out how many mm equals a degree. I don't want to take off too much, so I am starting at 1mm and then will re-measure with the degree wheel.
 
In duration. 136/107/141 with a blow down of 14.5. Exhaust seems a little low, Intake inst bad.

I've never ported a saw this small but how does this sound? 144/114/148 BD 15
 
In duration. 136/107/141 with a blow down of 14.5. Exhaust seems a little low, Intake inst bad.

I've never ported a saw this small but how does this sound? 144/114/148 BD 15

the first numbers are the ones you posted but in duration. The second set is my proposed numbers after porting
 
To find tdc or bdc numbers from duration you take the duration divide it in half. Take that number and subtract it from 180. 180 total duration. So 136/2= 68. 180-68= the exhaust height of 112. I like measuring port timing in duration. Just my preference. I’ve never ported a saw without doing some machine work on it so my numbers may or may not be good. I was hoping huskihl would chime in. But yes I think it needs more exhaust. I would lower the intake some and raise the exhaust some.
 
So what you achieve with raising the ports is basically a higher rpm/hp, at the cost of torque and long-livety I would guess?
Because I know that much about physics - it always comes with a cost...
 
You kind of have to feel how the saw runs before making too many decisions about what you want to do. Is it a higher strung saw as it sits or does it tractor along no matter how much wood it’s in? Being only 35c, I’d keep the exhaust down as low as I could. My exhaust height on ported 50cc saws is between 106 and 109. At 35cc, I’d be looking for 110-112. It takes a bigger carburetor to support a higher exhaust and more RPMs, and echoes aren’t noted for having large carburetors
 
In duration. 136/107/141 with a blow down of 14.5. Exhaust seems a little low, Intake inst bad.

I've never ported a saw this small but how does this sound? 144/114/148 BD 15

So 108-110 exhaust, lower the intake a bit, polish it up, advance the timing and report back.

I think the last 50cc saw I did had a 106 exhaust and it was a beast.
 
I worked on the cylinder today. Widen the exhaust and smoothed it out. So far I have the lower auxiliary transfers and exhaust done. Next is the intake.

I did find out that my grinder doesn't fit in the cylinder. So it looks like the upper transfer will remain stock. I might be able to cut down my burr to be able to it in the cylinder.

IMG_9456.JPG IMG_9453.jpg
 

Latest posts

Back
Top