Echo cs 590,600,620 porting/mod/build thread

[Red97]

my wrist watch needs a new gear can you machine me one

You get no gear and like it...

Watch is still right 2 times a day, how many times ya need to check it

 

[jake wells]

You get no gear and like it...

Watch is still right 2 times a day, how many times ya need to check it

well aint ye the smartass tonight haha.

 

[Locust Cutter]

Subbed

 

[Red97]

I stole this little gem of a brand new 490 off Fleabay for 250 to my door.

Saw bone stock and brand new in 12ish inch green wild cherry:

I pulled the tube from under the deflector and cut the front off of the deflector.

Nothing fancy but, I cut some simple gills on the other side of the muffler.

And now it seems much happier.

Good platform for a nice porting.

Very nice, thank you for sharing.

 

[jake wells]

here is a exploded view of the echo cs 590

 

[Woodpecker]

here is a exploded view of the echo cs 590
View attachment 15647

Your chains loose.

Seriously though that's a pretty cool display.

 

[echoshawn]

here is a exploded view of the echo cs 590
View attachment 15647

How'd they do that? Tannerite?

 

[Making Sawdust]

I thought it was a cool hot saw until I looked a lil closer and read what it was lol, dam phone it's hard to see the pics sometimes

 

[mdavlee]

With that long stroke the higher exhaust will work.

 

[Red97]

With that long stroke the higher exhaust will work.

I was wondering if you would chime in.

Think I'm gonna take the exhaust up to 104 ish 16-17 blowdown.

My other 590 arrived yesterday, but the oiler is stuck to the clutch. Gotta make a tool for clutch removal. Ordered stuff to rebuild both saws, just playing the waiting game now.

Think I will start the 490 tomorrow.

 

[mdavlee]

I was wondering if you would chime in.

Think I'm gonna take the exhaust up to 104 ish 16-17 blowdown.

My other 590 arrived yesterday, but the oiler is stuck to the clutch. Gotta make a tool for clutch removal. Ordered stuff to rebuild both saws, just playing the waiting game now.

Think I will start the 490 tomorrow.

Had to catch up. I hadn't ready any of this thread yet.

 

[jake wells]

I was wondering if you would chime in.

Think I'm gonna take the exhaust up to 104 ish 16-17 blowdown.

My other 590 arrived yesterday, but the oiler is stuck to the clutch. Gotta make a tool for clutch removal. Ordered stuff to rebuild both saws, just playing the waiting game now.

Think I will start the 490 tomorrow.

the 490 is a odd looking piece - o - machinery on the inside

 

[Four Paws]

16-17 blowdown.

Why?

 

[Red97]

Why?

I think it will help raise the powerband, while still keeping a bit of torque.

With the area of the transfers already, I think it will be able to get plenty of mix and velocity with that amount of blowdown.

You think it could use a bit more blowdown?

 

[Four Paws]

45mm bore 37mm stroke, is what complicates things

It's a gift.

I think it will help raise the powerband, while still keeping a bit of torque.

With the area of the transfers already, I think it will be able to get plenty of mix and velocity with that amount of blowdown.

You think it could use a bit more blowdown?

I would personally not be so eager to raise the transfers.

 

[Red97]

It's a gift.



I would personally not be so eager to raise the transfers.

Ok, trying to wrap my head around what you are suggesting.

Don't fully understand what the longer stroke is helping. More distance traveled per degree of crank rotation. Compared to other 60cc saws.

Ex sounds good around 105. Then leave the transfers in the 125-30 range?

Factory 620 is 105 and 124 without base gasket. So 19 20 stock on the hotrod version.

I plan on installing the 620 coil. As it has a different ignition curve, along with being unlimited.

Would like this to be a 20" bar saw. In my mind I can sacrifice some of the factory grunt. For an extra 1000-1500 rpm.

Could you please explain how you would build it? With #'s and why?

I am just trying to see what you do.

I have a couple other jugs to play with, to try some different numbers.

Thank you for encouraging the discussion, I am just trying to learn.

 

[jake wells]

the 490's pull a 20'' in hardwood all day long. bone stock with only a carb tune they pull good but don't have a lot of speed.

 

[Red97]

the 490's pull a 20'' in hardwood all day long. bone stock with only a carb tune they pull good but don't have a lot of speed.

Haven't got to the 490 yet.. it will get is own thread eventually.

Still thinking bout the 590.

But yes the 490 does seem to have good pull for a lil saw. That is tomorrows project.

 

[drf256]

Ok, trying to wrap my head around what you are suggesting.

Don't fully understand what the longer stroke is helping. More distance traveled per degree of crank rotation. Compared to other 60cc saws.

Ex sounds good around 105. Then leave the transfers in the 125-30 range?

Factory 620 is 105 and 124 without base gasket. So 19 20 stock on the hotrod version.

I plan on installing the 620 coil. As it has a different ignition curve, along with being unlimited.

Would like this to be a 20" bar saw. In my mind I can sacrifice some of the factory grunt. For an extra 1000-1500 rpm.

Could you please explain how you would build it? With #'s and why?

I am just trying to see what you do.

I have a couple other jugs to play with, to try some different numbers.

Thank you for encouraging the discussion, I am just trying to learn.

Think I actually understand this now.

You're gonna be physically lower with your exhaust at the same degree of opening because the piston has moved more distance in 105* of rotation than a shorter stroke motor.

As for the transfers, it's a quad with relatively short ports with a decent amount of area. You want more blowdown. A lot of the OEM's run 20-30*. I feel that 20-22* is a good number myself for performance on a quad. 13-16 on a dual port.

If you raise those trannys too much, you're gonna blow fresh charge right out that higher exhaust port.

Also, realize that the transfer and exhaust roofs will be physically much further apart at the same blowdown than a similar engine with less stroke. Uncork your exhaust and they are going to act physically higher at the same height. I'd start out leaving them alone also.

I definitely had it a bit back asswards in my brain. Think I get it now. Fascinating stuff.

 

[Four Paws]

Factory 620 is 105 and 124 without base gasket. So 19 20 stock on the hotrod version.

Look at the muffler. Start with the muffler. Do nothing but gut the muffler and see what happens. Then understand why it happened.

Then start looking at other areas for improving, specifically the intake tract.

Would like this to be a 20" bar saw. In my mind I can sacrifice some of the factory grunt. For an extra 1000-1500 rpm.

Could you please explain how you would build it? With #'s and why?

I am just trying to see what you do.

There is way more to it than numbers and what numbers I would use.

Think of this saw as a diesel truck. You want it to beat a car with a small block. Capitalize on torque. It can pull a bigger gear.