Echo cs 490 porting

[Red97]

Got some grinding in. Got exhaust to 106.5 without extra tricks.

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That is looking very nice. Do you use carbide burrs,or stone/diamond coated bits?

What did you got to for width? 65%?

120ish transfers ?

Wondering if you could Check the piston pin diameter vs that 346 piston.

A 44mm husqvarna piston might be a viable option for single ring setup. Just brainstorming out loud.

Anxiously waiting to see what kind of gains you end up with.

 

[drf256]

I went 65%. I'm not done.

 

[drf256]

That is looking very nice. Do you use carbide burrs,or stone/diamond coated bits?

What did you got to for width? 65%?

120ish transfers ?

Wondering if you could Check the piston pin diameter vs that 346 piston.

A 44mm husqvarna piston might be a viable option for single ring setup. Just brainstorming out loud.

Anxiously waiting to see what kind of gains you end up with.

It got late fast last night. I'll get you the pin measurements.

I hope to get it done before day's end.

Did you figure anything out with the carb?

 

[drf256]

I think I found the bottleneck in these ports. It may be why the saw runs out of steam. I don't see a lot of flow happening here.

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[drf256]

The 346 pin is 10mm in outside diameter Red.

Here's another pic of the tiny 490 ports, this with a penny for perspective.

These are gonna need a few hours of TLC.

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[bikemike]

I think I found the bottleneck in these ports. It may be why the saw runs out of steam. I don't see a lot of flow happening here.

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Choked off might need some chain file action

 

[drf256]

They need attention for sure.

There's a lot of potential in this little jug. I don't think I'll have it done today.

 

[Red97]

It got late fast last night. I'll get you the pin measurements.

I hope to get it done before day's end.

Did you figure anything out with the carb?

I won't be back home till late next week to experiment with my carb ideas. But I have lots of time to think/research, and I will have a few different carbs to play with when I get home.

I think I found the bottleneck in these ports. It may be why the saw runs out of steam. I don't see a lot of flow happening here.

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The 346 pin is 10mm in outside diameter Red.

Here's another pic of the tiny 490 ports, this with a penny for perspective.

These are gonna need a few hours of TLC.

Sent from my iPad using Tapatalk

Yeh, I seen that, lots of time getting it opened up the way I wanted.

Wonder if the echo uses a 10mm pin? Probably not, they just have to be different lol.

 

[drf256]

I see where you're going here. I will check.

So you opened yours?

 

[Red97]

I see where you're going here. I will check.

So you opened yours?

I did.

And looking for a single ring piston too. Would be nice to just cut a flat roof/band.

 

[bikemike]

I won't be back home till late next week to experiment with my carb ideas. But I have lots of time to think/research, and I will have a few different carbs to play with when I get home.

It is jap so it will be a metric something





Yeh, I seen that, lots of time getting it opened up the way I wanted.

Wonder if the echo uses a 10mm pin? Probably not, they just have to be different lol.

 

[awol]

If the Echo uses the small pin, a 246 piston may be an option, or even a 5000+/jonsered 490. Both are single ring, with a flat top.

 

[Red97]

If the Echo uses the small pin, a 246 piston may be an option, or even a 5000+/jonsered 490. Both are single ring, with a flat top.

Thank you. That opens up some more options.

You ever built one of these small echo's?

 

[awol]

No I haven't, but you all have sure got me thinking about 'em! I ran Matts 500 a while back, and the only thing that impressed me about it was the light weight.

 

[echoshawn]

No I haven't, but you all have sure got me thinking about 'em! I ran Matts 500 a while back, and the only thing that impressed me about it was the light weight.

Been told you build a mean 590/600.
Jump in the ring!

 

[bikemike]

Is it timing advanced? Can't remember if I asked that. Both my echos took well to a advanced timing 360t and cs510 360t made a big difference

 

[Red97]

No I haven't, but you all have sure got me thinking about 'em! I ran Matts 500 a while back, and the only thing that impressed me about it was the light weight.

Definitely a light weight, hoping to squeeze out a few more rpm to make a great limbing/small wood saw. What a 50cc should be.

Is it timing advanced? Can't remember if I asked that. Both my echos took well to a advanced timing 360t and cs510 360t made a big difference

I haven't tried yet. Never even pulled the flywheel. Might try .005 off the key at a time, just for gins and giggles.

When I get back, I am going to adapt the 510 style filter, see if that gains me anything. Then start working on carbs...

 

[echoshawn]

Is it timing advanced? Can't remember if I asked that. Both my echos took well to a advanced timing 360t and cs510 360t made a big difference

Been told by 2 different builders that it doesn't seem to respond to a timing advance.
It'd be nice to see someone prove that wrong lol

 

[bikemike]

Definitely a light weight, hoping to squeeze out a few more rpm to make a great limbing/small wood saw. What a 50cc should be.
Send me a pic of the back side of your carb lookin into the venturi.
Timing advance is easy cause they have a woodruff key so you can always go back if needed


I haven't tried yet. Never even pulled the flywheel. Might try .005 off the key at a time, just for gins and giggles.

When I get back, I am going to adapt the 510 style filter, see if that gains me anything. Then start working on carbs...

 

[bikemike]

On the jug of that saw with the narrow transfer ports I'd chuck up a chain file and make it a bit wider. I heard the file in a drill trick not long ago and had to try it on a exhaust flange and it worked vertical well