Echo 501P. Let's play!

[Simondo]

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Is the nut holding on the sprocket instead of a C clip a "Echo" thing ?

 

[Red97]

Is the nut holding on the sprocket instead of a C clip a "Echo" thing ?

Just on these little ones.

The 590-620 have a clip. 680-800 are outboard clutch.

 

[Backtroller]

It has a nice windowed piston in it. View attachment 40186

I'm impressed. That piston sure looks cast far better than any of the Mahle Pistons out of my Stihls. Also all of the beveling in the cylinder was much cleaner than on my 421 too. Might have to pick up an Echo at some point.

 

[Miller Mod Saws]

Ok boys. I've already ripped it apart. I started by taking .025 off I base. The saw held rpm better and had a tad more torque. So back apartvit came. And here's where I'll give you some numbers.

 

[Miller Mod Saws]

I ended up so far taking .039" off the base which left me with .021" squish. Again squish is funky to measure on these. It's hard to see but its squishing just in off the edge of my solder.

 

[Miller Mod Saws]

Again it felt like the saw gained some but no real head turning results. At this point my exhaust is sitting at 114 and intake at 79.

 

[bikemike]

@WSE15 showed a tach pic of 14,700 said it just ran out of fuel.

Doubt it is a limited coil, if it is that extra 1000+rpm is gonna be beneficial on this size saw anyway.

When I seen the piston on the ipl, figures for sure it was a center fed quad jug. Wondering if the piston is any lighter at all? full size pin, seems plenty thick around the windows.

Don't really see the windows helping much with the way this jug is..

Transfer tunnels /outlet look really similar to the 590. without the relief on the lower tunnels or the stagger.

590 really like a symmetric opening. from the wash pic posted, it does not appear the secondary has much flow once the small primary opens.

Feel it will really pickup opening flat or 2* stagger, think more than that is killing secondary flow.



That can also backfire, with enough pressure the fresh charge can "cut" through the burnt gas and exit the cylinder. leaving a bunch of already but gas to mix with fresh charge in the chamber.

Echo is not above the epa here. They have to come up with ways to pass the "sniff" tests without going strato. Have a feeling that is the reason for such plugged up mufflers, coupled with less burnt gas being expelled. Makes it easier to pass the emissions. Just my take on what they trying to do.

I'm anti epa unplug the exhaust and carb and let the chips fly

 

[Miller Mod Saws]

Hopefully I can make a vid tomorrow but here's What I did as I tore it down again. The factory exhaust is 52% width. So i widened it to 64% and raised it back to 110. I then raised the lower skirts up some where the transfers are.

 

[Miller Mod Saws]

At this point I have not touched the trans or the intake. Other than gaining duration on the intake because of the jug lowering. I will try and get it back together tomorrow and get a vid. Depending on how it reacts. This maybe my final step till I get saw 2 in house. Lol.

 

[jake wells]

all of my echos use a nut instead of a clip to hold sprocket on.

 

[drf256]

I'm not understanding the placement and shape of the uppers here. The larger intake ones (?secondaries) seem like their placement would be better for cross than loop scavenging.

I'm seeing the ex uppers (mains) forcing a jet of charge towards the intake wall and colliding with the secondaries charge to force the loop up and along the intake wall.

I could be wrong (happens a lot), but I think you need a nice delay between opening those transfers or it will hurt the Saw.

 

[Red97]

590 transfers.

590 has a 45mm bore...

 

[Miller Mod Saws]

Ok boys. I played just a little tonight. lol here's I'll I've done. I took .039" off the base to hit a .021" squish. The factory exhaust port is 52% width. I widened it to 64% and raised it back up to 110. This picked me up roughly 3 sec in the cut. Or a 14% more gain. Transfers and intake untouched.

 

[Miller Mod Saws]

 

[RI Chevy]

Sounds good and strong for an Echo. What chain are you using? .325?

 

[bikemike]

I don't know if I'd do much more to the saw. Runs real nice rpm under load and will gain more as the saw frees up. just run the piss put of it. document your work and save that info for more builds youl have happy customers

 

[Miller Mod Saws]

Sounds good and strong for an Echo. What chain are you using? .325?

325 lpx.

 

[RI Chevy]

Wow. Ok. Nice job with the build. You happy with the results? Anything left in it?

 

[Majorpayne]

325 lpx.

20 inch?

 

[RI Chevy]

Looked like a 18" bar to me.