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

[Red97]

Thanks for starting this thread Red.

Nice muffler deflector

My understanding is that the 620P has a totally different jug and timing than the 590/600.

Where is the ring pin?

Those uppers are pretty beautiful. I can't see any gains there myself.

The ring pin is above the intake, like most husqvarna's.

Yes I have read the 620 has different part numbers for the piston and cylinder, but it is the same bore/ stroke. So it should be possible to get the same type of performance out of this 590 jug.

From what I have gathered, these run really loose squish .04+/-. With a restrictive muffler and exhaust port size.

Yes the transfers look pretty nice, but the (intake side) transfer is huge. And enters the cylinder at a 45*. And the exhaust side transfer is tiny, like 1/4×3/8.

I don't think it will need a lot of hogging, just some reshaping, and port timing adjustment should make a strong runner.

 

[Red97]

i had a 590 a few months ago and it was down right nasty did a base gasket delete went whole hog on the muffler pulled the limiters and replaced the limited coil in it from a 620pw.
added a 620 wrap handle to. pulled a 24'' like nobody's business had great torque and the power band was smooth plus it was reliable but my old man needed it so i sent it his way.

How would you say it compares to your stock 365?

 

[jake wells]

the 365 has more speed than the 590 but the torque feels the same.
one big improvement to me on the 590 is a 8 pin rim instead of the 7 it pulls the 8 fine.

 

[Czed]

I've got a cylinder on the way to grind on I have two 590s thanks for the 620 coil suggestion I'll do a gasket delete already gutted the mufflers they sound good like an old mx 80 .

 

[Jughead]

Sawtroll 3...2....1......

 

[Red97]

Sawtroll 3...2....1......

Yada Yada yada....

Just trying to make this the best echo it can be.

Maybe with a lightweight bar the sideways balence will be ok...

 

[Poleman]

jake...did you feel the unlimited coil was a benefit?? I'm thinking it would be, as it seemed the saw was held back by it in comparison to the 620.

Truly NICE saws with lots of power and torque!!!

 

[Red97]

What are the factory coils limited at?
Where are these saws set at stock? 12,500?

 

[Poleman]

I'm thinking 12,8..... but not certain on that. Sure seem like the 590 could use a few more r's!!

 

[Jughead]

Yeap the coil was holding my cs600 back big time.wish i hadn't have sold that one.i loved that saw.

 

[Czed]

I think sawtroll gave up on this subject he always shot me down on this and other saws that were beneath him that I owned or was working on for people but I always liked his knowledge of the saws he liked .

 

[Ozarker]

What are the factory coils limited at?
Where are these saws set at stock? 12,500?

No idea on the 590/600. Someone write to Echo and ask. I did, regarding the CS400, and they responded that it kicked in at "around 15,000 rpm."

 

[bikemike]

I wish walbro would make the coils programmable so they curve, advance, and rev limiter could be played with. I love my 360t but I hate the coil rev limiter they need to spin 14k 15k cause rpm is of a saftey issue when a fast cut is needed

 

[Red97]

Ouch..

Now for some port timing numbers.
In, 78. duration 156
Ex, 113. Duration 134
Tr, 130. Duration 100

Squish .042 with base gasket.
Base gasket .017

My plan, take .025 off the base. Cut the squish band parallel to the band cut in the piston. Set squish at .018-.020.

Then figure out where I can get my ports without losing too much velocity.

 

[Simondo]

Ouch..

Now for some port timing numbers.
In, 78. duration 156
Ex, 113. Duration 134
Tr, 130. Duration 100

Squish .042 with base gasket.
Base gasket .017

My plan, take .025 off the base. Cut the squish band parallel to the band cut in the piston. Set squish at .018-.020.

Then figure out where I can get my ports without losing too much velocity.

Any ideas what is messing up these top ends ? This isn't something that iv seen mentioned much .

 

[Czed]

Both of mine were lean from the factory had to pull the limiters and people sometimes straight gas a saw and return it when they are finished with a job we sell poulans and accept returns no questions asked.

 

[Red97]

Ok, I mathed it correctly...

.025 off the base, just kissing the squishband. Tomorrow I'll cut .020-.022 out of the band, then figure out the ports....

 

[Poleman]

Interesting....All the ones I've seen have been rich from dealer/factory.

 

[Jughead]

Interesting....All the ones I've seen have been rich from dealer/factory.

mine was too but im at over 2000ft

 

[Red97]

Set the squish, angled the tool bit to match the piston.


Used the old piston to sand the band,



Didn't work as well as I had hoped. Left a ridge around the edge, so I recut it with the mandrel. Finish isn't the best but it will work. Squish Set at .021