Echo 7310 build thread

[Mastermind]

Thanks for the build thread Brett.

I'm not a fan of those transfer caps. But the rest is pretty cool.

The carb.....is it tunable? On many Echo saws, getting it lean enough to make RPM is impossible without some mods to the carb.

 

[Red97]

Thanks for the build thread Brett.

I'm not a fan of those transfer caps. But the rest is pretty cool.

The carb.....is it tunable? On many Echo saws, getting it lean enough to make RPM is impossible without some mods to the carb.

I have not heard if any of the rich tuning issues with this model.

I've not dug into mine yet.

I did have 1 person mention wanting to further tune (add holes) for a bit more fuel....

Hope to be into mine soon.


Very excited to see how this one comes out.

Great thread for sure.

 

[GoBigBlue1984]

I’ve tore this saw back down for some changes. More on that later...

but here is the initial cut.

28” full comp/full chisel. Chain isn’t the greatest. Red oak crotch. I’ll get the next video in cants.

So far, this saw woke up a good deal. It needs more balls. But short of cutting the head off and machining one with a smaller chamber and wider band.....I’m stuck.

 

[GoBigBlue1984]

So far, this saw woke up a good deal. It needs more balls. But short of cutting the head off and machining one with a smaller chamber and wider band.....I’m stuck.

Or a different piston with taller crown, that will allow me to cut more from the band. Anyone got a 757 piston they can offer some measurements from?

 

[huskihl]

Or a different piston with taller crown, that will allow me to cut more from the band. Anyone got a 757 piston they can offer some measurements from?

Could still take .020” from the band and lose the gasket

 

[Mastermind]

I'm gonna let you fellas have this one. If someone asks....I'll send them to one of y'all.

 

[Nutball]

I think a higher exhaust would be worth a try, it sounds like you have a little room to lower it more if need be, maybe even loose the top ring.

I'd also experiment with the intake. Epoxy it up to maybe 75 and go down from there, making timed cuts each time.

If you do drop the cylinder more, maybe try leaving the transfers where they are to see how a little extra case compression helps, considering all that transfer area.

 

[Red97]

Keep top ring...

Drops the comp a lot more than one would think...

 

[Nutball]

Keep top ring...

Drops the comp a lot more than one would think...

I've always wondered about that. I've assumed it would too, but people seem to claim the reduction in friction is worth it.

Then again, some say rings are mainly just for starting, and the heat expanded piston is what maintains good compression.

I can't say I've noticed much difference in compression or performance between a 590 single ring, and 620 double.

 

[Funky sawman]

When I sawed with a 2100cd, instead of running a thin ring piston, I ran a normal piston with one ring, still plenty of compression, and I would run it at 12,000 rpm with gov valve plugged

 

[Red97]

I've always wondered about that. I've assumed it would too, but people seem to claim the reduction in friction is worth it.

Then again, some say rings are mainly just for starting, and the heat expanded piston is what maintains good compression.

I can't say I've noticed much difference in compression or performance between a 590 single ring, and 620 double.

You can remove the bottom ring and not notice a compression difference.

But removing the top ring drops the comp a good amount.

 

[NightRogue]

Runs good, you need to plan further "improvements" carefully. I suspect it could go backwards if approached wrongly, higher ex with pop up maybe?

Sent from my INE-LX2r using Tapatalk

 

[GoBigBlue1984]

Runs good, you need to plan further "improvements" carefully. I suspect it could go backwards if approached wrongly, higher ex with pop up maybe?

Sent from my INE-LX2r using Tapatalk

I’m not a fan of pop ups and I ate a top end and port work on a 660 a couple years back when my epoxy came loose in the log woods.

I’ll use it on my saws but will likely not use it on a customers saw again. Guys do it all the time, I know. Prep is everything when using epoxy. I’ve learned.

That being said, I’m not risking eating another top end if I don’t have to. So I’m not looking to epoxy the intake and taking anymore off the base would put me in the duration range that I’d rather stay away from.
But I like the input and the recommendations.......this is what makes it fun. Keep em coming, buddy.

 

[NightRogue]

I’m not a fan of pop ups and I ate a top end and port work on a 660 a couple years back when my epoxy came loose in the log woods.

I’ll use it on my saws but will likely not use it on a customers saw again. Guys do it all the time, I know. Prep is everything when using epoxy. I’ve learned.

That being said, I’m not risking eating another top end if I don’t have to. So I’m not looking to epoxy the intake and taking anymore off the base would put me in the duration range that I’d rather stay away from.
But I like the input and the recommendations.......this is what makes it fun. Keep em coming, buddy.

Agreed, everyone have bad experience with something while rest of the crowd might not have encountered.

What was the port timing again?

Sent from my INE-LX2r using Tapatalk

 

[Funky sawman]

Not a fan of popups here either, sometimes I rebuild my saws out in the bush, and I usually carry seals, a carb and a piston if I'm way out camping on the job site. That's no place for a professional saw with a custom piston. That said, if I ever owned a saw with a custom piston, I would have the builder cut crowns on a couple of them for spares

 

[Nutball]

I try to grind a little trench around the port edges, so if the whole chunk of epoxy comes loose it is too big to come out in any direction. But that wouldn't stop vibration from shattering it. Some say it will break up through the engine without causing damage because it is so soft, but I've always had my doubts on that one.

 

[Mastermind]

After using JB Weld in literally hundreds of intake ports without any issues, I'm not at all concerned about using it. I tried Devcon for awhile, but JB Weld is at least 10 times better for this application.

 

[full chizel]

Is Shindaiwa supposed to come out with this saw too?

 

[Red97]

Is Shindaiwa supposed to come out with this saw too?

Yes

 

[Homelite750]

Here’s the shindaiwa.