Echo 6700 build

[Red97]

I guess you got that 670, huh?

What a wacko that seller was.

Isn't it one clean saw?

Yessir, very clean.

Thank you for fetching it.

 

[Red97]

@jmssaws

This is what I'm working on...

Really similar to 044, but that tiny exhaust...

Since the comp is so high, thinking it can be a stronger saw taking the ex up 3-4 degrees. Mostly for the time/area.

First dual port, wasn't exactly sure where I wanted to go, just think it has a bit more left in it.

Maybe a timing advance too, 25* stock.

 

[jmssaws]

No doubt less compression would help but I'd open the chamber instead of raising the exhaust.
What's the port timing?
It has no ignition advance?

I've seen a bigger carb not help at all,it can only take in as much as it can get out.

 

[Red97]

No doubt less compression would help but I'd open the chamber instead of raising the exhaust.
What's the port timing?
It has no ignition advance?

I've seen a bigger carb not help at all,it can only take in as much as it can get out.

Piston swap, likely cut through the top..

Very small exhaust, for 66cc imo, just thinking raising it will help more than hurt, possibly stretch the bd in the 24/5 range. Feel the tunnels are a little tight, a bit more pressure may be a good thin here..

Current numbers are 101, 123, 81
Stock timing key
Think you are correct on the bigger carb, just what I had to rebuild at the time. Have a good small carb to try now.

Jus feel it is missing something.

 

[jmssaws]

If it's gaining without a filter the a bigger carb won't help,get that problem fixed then work on getting more through the intake and transfers until you max the exhaust port then it's probably strong as it can be.
I would think 200 or less would be where I'd go

 

[jmssaws]

Piston swap, likely cut through the top..

Very small exhaust, for 66cc imo, just thinking raising it will help more than hurt, possibly stretch the bd in the 24/5 range. Feel the tunnels are a little tight, a bit more pressure may be a good thin here..

Current numbers are 101, 123, 81
Stock timing key
Think you are correct on the bigger carb, just what I had to rebuild at the time. Have a good small carb to try now.

Jus feel it is missing something.

What it at with a oem piston?
Less compression and lower durations?

 

[Red97]

What it at with a oem piston?
Less compression and lower durations?

Yes, stock was 74, 103, 122 .04x squish comp 150 ish



Center to center of bolt holes is about 63%



I got it to right around 60% but seems pretty small still is the only reason im thinking going higher may help..

Thanks for the input

 

[jmssaws]

A 064 or 066 with a oem piston can't be much wider than 60%

Sounds like it's held back,probably the compression.

Ignition advance could be a big gain

 

[Red97]

A 064 or 066 with a oem piston can't be much wider than 60%

Sounds like it's held back,probably the compression.

Ignition advance could be a big gain

This piston will handle 70% easy enough, don't think the jug will lol

.020 off the key sound like a good place to start? never played with timing before.

Im gonna try raising the ex up to 98*

Still have 2 more of these to go if I don't like it, but that should get the comp down round 200.

 

[jmssaws]

020 is good
I don't think you will loose that much compression but the extra bd could help.
At bdc is the crown still in the uppers?
Might not be opening them much.

 

[Red97]

020 is good
I don't think you will loose that much compression but the extra bd could help.
At bdc is the crown still in the uppers?
Might not be opening them much.

I will have to check the crown, but I Dont believe it is.

Might try and get back into this one tommorow.

 

[drf256]

Joe....

You have excellent machining skills buddy.

If you send me a 670 jug that cleaned up, I'll slather 4043 all around that exhaust port for ya. You can resurface it and move the holes.

Voilá!

 

[Red97]

Joe....

You have excellent machining skills buddy.

If you send me a 670 jug that cleaned up, I'll slather 4043 all around that exhaust port for ya. You can resurface it and move the holes.

Voilá!

Hmm, might have to take you up on that on one of these..

Maybe the jug that is gonna get the pipe.

Thank you for the offer.

 

[huskihl]

Hmm, might have to take you up on that on one of these..

Maybe the jug that is gonna get the pipe.

Thank you for the offer.

One Echovarna with really wide exhaust port, coming up.

 

[Red97]

Well, you can tell where the chamber is..



Red armor doing it job @ 40:1



The shiny ring is 50% band area. Wanted to drop the comp a bit anyway.



Opened up, Tryed to somewhat radius it into the cone shaped chamber.

 

[Red97]

Took the ex up to 99, in search of more area.



Transfers up to 119.

Shaved the key .020, definitely seemed to help throttle response a lot.

So opened the chamber up, timing advance. Numbers are 99,119,82

I'll see where the comp ended up tomorrow.

Have to gather up some more test logs...

 

[Backtroller]

Looks really good Joe. Can't wait to see the video.

I missed the radius the first time I looked at the pictures. Nice touch.

 

[Red97]

Looks really good Joe. Can't wait to see the video.

I missed the radius the first time I looked at the pictures. Nice touch.

Thank you,

Think it is pretty close.. I have to remember it is just a 66cc saw.

Think the next one will get a base gasket keep the intake up a bit, leave more meat to shape the chamber a bit better.

The cone shape isn't the best for scavenging, as seen by the piston wash. Nor for maximum power potential.

 

[Larry Joe]

Hmm, might have to take you up on that on one of these..

Maybe the jug that is gonna get the pipe.

Thank you for the offer.

I have a 670 jug with a lot of transfer, it should clean up. You're welcome to it if you want it. It's just taking up room here.

 

[Red97]

I have a 670 jug with a lot of transfer, it should clean up. You're welcome to it if you want it. It's just taking up room here.

That would be awesome.

Trade for some muffler deflectors?