Someone getting an Echo cs 590 For X-MAS

[paragonbuilder]

This is a excellent discussion.

That was a slick clean up bro!


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[Red97]

New oil pump, worm, bearing. Even hooked ya up with a rim drum setup.

 

[Woodpecker]

New oil pump, worm, bearing. Even hooked ya up with a rim drum setup.

This is going to be one mean sleeper saw!

 

[Four Paws]

Making some progress I see.

Have you been studying your piston/crank/port geometry? Come to any revelations? Or have you been focusing on carburetor modifications?

 

[Red97]

Making some progress I see.

Have you been studying your piston/crank/port geometry? Come to any revelations? Or have you been focusing on carburetor modifications?

Just carb mods..

Hopefully get it machined/ squish set tomorrow. See where everything ends up, do some layout. Then see how things look with a piston in the bore.

 

[Red97]

On my way to .038 off the base



Done



Hmmm I wonder dot dot dot

 

[Red97]

82,114,135

 

[Red97]

Now the question is pop up or tapered band????

Since I use the edge of the dome it dosent change the numbers.

Stock band isn't very close to matching the piston. Pop up was just kissing at tdc with .038 off the base

Or take .030 out of the band matching the taper of the stock piston..

What you fellas feeling?

 

[Red97]

Ok, Its getting a popup

A lighter piston can never hurt..

 

[Four Paws]

Now the question is pop up or tapered band????

What you fellas feeling?

30 minutes later...

Ok, Its getting a popup

A lighter piston can never hurt..

Patience isn't a virtue?

The good new is, pistons are cheap. You can test and tune - and you can always go back to a stock piston, revising your porting.

Plus, you still have like 87 days until Christmas.

 

[Red97]

Well its done..



First attempt at a pop up with scored piston, just enough to prevent Freeport.



Some layout, whopping 62% on the exhaust



Raise the transfers a bit, may end up going higher.

Squish set at .020

That will be tomorrows project.

 

[Red97]

30 minutes later...



Patience isn't a virtue?

The good new is, pistons are cheap. You can test and tune - and you can always go back to a stock piston, revising your porting.

Plus, you still have like 87 days until Christmas.

Im not a doctor, I don't need any patience

Decided on a popup for a couple reasons.

1, Flat squish band
2, Just flattening the piston to the edge wont change port timing like most other saws.
3, Don't have to account for the piston taper during layout.

 

[Nitehawk55]

that + GFY in the jug will add some good mojo for sure !

 

[Red97]

Exhaust finished. 63% width.



What 22* of blowdown looks like in the 590.. Top of the piston will be at the bottom of the ring when the transfers open.

Should be plenty of time to clear the chamber



Transfers set. Didn't widen them any, opened up the pinch point in the tunnel, and flattened the edge on the intake side transfer.

105, 127, 82

Just roughed up the intake.

I tried to even out the Port width, Intake exhaust transfers are all in the 60-63% range.

Still have a bit of massaging to do on the lower transfers.

Try to finish it up tomorrow.

 

[Red97]

Muffler mod. Removed the small deflector, leaving just the large one. That way the future owner can run the screen if need be.





Cleaned up pretty well..

Need to grind up a good loop and mod another carb. Probably Tuesday before I get back to it.

 

[Four Paws]

Whoa, what happened to all the discussion surrounding the lower transfers and the piston?

 

[Red97]

Whoa, what happened to all the discussion surrounding the lower transfers and the piston?

Nobody was discussing, so I just went with it.

Gotta get some fuel through it.

 

[Mastermind]

I don't mess with the lower transfers in these saws either. Compared to many other quad port engines the transfer entrances are huge.

 

[drf256]

Looking good Joe.

 

[Four Paws]

I don't mess with the lower transfers in these saws either. Compared to many other quad port engines the transfer entrances are huge.

But are the transfer entrances well refined from the factory?

I have never seen a set of lowers that wouldn't benefit from case matching.

Nobody was discussing, so I just went with it.

And in regard to the lowers and the piston, what did you decide on for this phase of the build?