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

[Ronie]

I got the top end off my 620 and it looks like it has barrel faced rings, you can see in the pic that only a thin line is making contact with the bore. I'm not real sure what I'm going to do with it, I think I'm going to cut the base, widen the exhaust, put the intake at 80 and stagger the transfers. I was thinking about doing a popup but there's not much material above the top ring. I got .038 squish with a .014 base gasket and I'm going to set it around .018 without the gasket. I'm also going to put a 199 jet in the carb.

 

[huskihl]

I got the top end off my 620 and it looks like it has barrel faced rings, you can see in the pic that only a thin line is making contact with the bore. I'm not real sure what I'm going to do with it, I think I'm going to cut the base, widen the exhaust, put the intake at 80 and stagger the transfers. I was thinking about doing a popup but there's not much material above the top ring. I got .038 squish with a .014 base gasket and I'm going to set it around .018 without the gasket. I'm also going to put a 199 jet in the carb.

View attachment 297693 View attachment 297694

When I made the pop up I came in flush from the top edge enough to clear the squish band and left the rest of the existing dome. After removing.030” or so from the band. It’s hard to make compression in these

 

[Ronie]

I'm still not there with cutting the squish band, maybe over the summer I'll get it down.

 

[huskihl]

I still not there with cutting the squish band, maybe over the summer I'll get it down.

Do you want some junk cylinders to practice on?

 

[Ronie]

Thanks for the offer but I have a few, just need to take the time to practice.

 

[Ronie]

I finished up my cylinder tonight and ended up with these numbers, EX 109, TR 127/130 staggered and flattened the ones closest to the intake, IN 80. I also ended up taking a little off the piston. I took a little to much off the base so I'm going to use a base gasket but won't be able to finish it up until it gets here.

 

[Ronie]

Couldn't wait any longer on a base gasket so I cut one out of some 1/64" gasket material and ended up with .017-.0175 squish and it passed a vac test. After a cup of coffee I'll get the rest of it together and see how it does. I was thinking about advancing the timing, has anyone tried it with the 620 coil?

Just wanted to add that I put the 199 jet in the carb and I cut the piston again because the angle wasn't right.

 

[huskyboy]

A lot of guys say they get popcorn advancing echo saws. Never did one yet so can’t comment on that.

 

[Ronie]

A lot of guys say they get popcorn advancing echo saws. Never did one yet so can’t comment on that.

I'll just leave it as is unless someone has had some good results doing it.

 

[Ronie]

All back together and got it almost right, no wow factor but it does pretty good for a 60cc saw.
14,400 WOT RPM

 

[huskihl]

I'll just leave it as is unless someone has had some good results doing it.

The newer Echo models that I’ve done won’t take anymore. I’ve actually retarded it and it can potentially free up some rpm

 

[Ronie]

I tuned it a little richer but started running out of fuel at the end of the first cut so that's as far as I can go today. 13,900 WOT RPM

 

[Ronie]

I liked that 620 so much that I picked up a 600 with a scored piston. I'm not sure what I'm going to do to it but I did cut a pop up on a Golf piston and set the squish at .017-.018 this afternoon.

 

[TreeLife]

I liked that 620 so much that I picked up a 600 with a scored piston. I'm not sure what I'm going to do to it but I did cut a pop up on a Golf piston and set the squish at .017-.018 this afternoon.

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Fond of mine even though it isn't much of a 620 anymore lol I considered another but left with the oem cyl and ported.

 

[Kerfed]

Still surprised how much I like the 620. Was planning on having it ported a year ago but it cuts damn good stock. Heresy around here I know. 20” full comp buried in red oak with torque to spare. Pulls a 24 full skip just fine, perfect for softwood and balance is almost level with lightweight bar.

 

[Ronie]

For the price you can't beat them. If they would lighten them and bump up the power some, they would be an even better saw.

 

[Ronie]

If you do a pop up, the 590/600 piston has more meat above the ring. I'm going to order a 590 piston for my 620 so I can get a little more compression.

OEM 590/600




Golf 590/600



OEM 620

 

[Ronie]

Finished the cylinder up, the numbers are, EX 113, TR 134, IN 81. Those numbers are off a little because I measured them with a ring and the piston is cut at an angle so the ring rides higher up on the piston and not on the outside edge, same goes for the numbers I posted for my 620. Also I did't change the upper transfers. Should have it all together tonight and see how it runs tomorrow.

 

[Ronie]

Muffler modded and all back together

 

[Kerfed]

Nice!