Echo cs 490 porting

[huskihl]

3/8 lo pro nk = light Saber on my 026. Smoother too

 

[Deets066]

The only other echo bar I have is a 14" in picco.

I'm wondering if an 8 pin on this saw and a 14 would be a light saber.

It would be if you could get some more rpm out of that girl. Nice builds fellas!

 

[Red97]

It would be if you could get some more rpm out of that girl. Nice builds fellas!

I have quite a few idea's to try.. from ignition, to carbs even air filters... it is going to get interesting for sure.

12-14 hours a day watching a mill go back and fourth I have lots of time for brain storming, forgot my notepad the first couple days.

 

[Deets066]

I have quite a few idea's to try.. from ignition, to carbs even air filters... it is going to get interesting for sure.

12-14 hours a day watching a mill go back and fourth I have lots of time for brain storming, forgot my notepad the first couple days.

First things that come to mind is a v stack with a good flowing filter and an unrestricted carb

 

[Red97]

First things that come to mind is a v stack with a good flowing filter and an unrestricted carb

Yes, yes, and I think I'm gonna try a big carb. Like 372 big along with some modified small carbs. Start small and work my way up until I don't notice any gains.

Make a v stack and try a more stock appearing a/f setup.

Also plan on adjusting the timing. Advanced and retard. Just to see.

 

[jake wells]

i looked on the echo global site and the give the hp rating of 2.91 of the cs 490 they have came out with a updated version of the cs 500p and it has boosted hp ratings from 2.91hp to 3.50hp. the 490 and 500p has the same hp.
here is the new cs 501 with a sexy bar on it 3.5 hp and comes with a decomp valve.

 

[drf256]

i looked on the echo global site and the give the hp rating of 2.91 of the cs 490 they have came out with a updated version of the cs 500p and it has boosted hp ratings from 2.91hp to 3.50hp. the 490 and 500p has the same hp.
here is the new cs 501 with a sexy bar on it 3.5 hp and comes with a decomp valve.
View attachment 16961

Any specs?

More CC's?

Maybe they just added one more tiny slit to the exhaust for it to exhale through.

Mines going to the CT GTG. I hope it gets a shot at a run on @wcorey dyno.

 

[drf256]

Yes, yes, and I think I'm gonna try a big carb. Like 372 big along with some modified small carbs. Start small and work my way up until I don't notice any gains.

Make a v stack and try a more stock appearing a/f setup.

Also plan on adjusting the timing. Advanced and retard. Just to see.

Yes, yes, and I think I'm gonna try a big carb. Like 372 big along with some modified small carbs. Start small and work my way up until I don't notice any gains.

Make a v stack and try a more stock appearing a/f setup.

Also plan on adjusting the timing. Advanced and retard. Just to see.

Joe,

I'm not a carb pro. Not even fair to say I'm a novice.

Maybe @Terry Syd can give us a hand?

In my limited experience, I've found that carbs that are too small are tough to lean out and ones that are too large can't be richened.

I've also seen, first hand, that opening a muffler has caused a saw to need the H needle turned in and not out as one would expect.

I think a stronger vacuum just pulls more fuel out of the nozzle. I've seen Terry Syd's posts where he closes off one H jet and opens the adjustable one.

If we can find a larger Venturi carb, that would be great. I think enlarging the Venturi on this one enough may drop the vacuum signal on its own. I am going to try this first, like Carl did.

I saw 13,550 with no air filter. It was over 13,500. I didn't want to piss rev or lean it too much as it was its maiden voyage.

I broke my intake boot retainer spring. I had to use a traditional 044 clamp on mine.

There's no video, because I ran out of time and daylight, but I had the 20" bar buried in oak and the saw was actually quite good with it.

I'm hoping to get some more footage next Saturday. I'll make an oak block and try to set myself up to do a few before and after shots in the same piece of wood.

 

[drf256]

I may raise my exhaust another degree and open the chamber a bit to lower my static compression.

So I'm at 106.5/121.5-122.5/82 right now. 238psi after a half tank.

I'm also wondering about notching the cylinder extension and notching the piston to match it at BDC. It's pushing all of it charge through maybe .125 at BDC.

@Mastermind @Miller Mod Saws @mdavlee @jmssaws @Deets066 @Moparmyway , any opinions?

My saw feels pretty good as is. I'm afraid my comp is gonna be too high after breakin. It needs more carb for sure.

I think the carb is the rate limiting step here. That's why we all did it a bit different but are getting the same results.

 

[mdavlee]

That may help some. That's a small area to flow through

 

[Moparmyway]

Matching everything @ BDC will gain some due to the lighter reciprocating weight and better aerodynamics in the case at high rpm

I'd be guessing about that exhaust, it seemed a little low to me when you guys first started this thread, so I decided to pull up a chair and see what happened.

I agree on the carb limiting you guys, and would look to alleviate that roadblock first, then decide what to do to the ports after. You could be chasing your tail untill that carb runs clean

 

[Miller Mod Saws]

That may help some. That's a small area to flow through

I agree with Mdavlee. On your squish did you cut it flat or angle it?

 

[Deets066]

Matching everything @ BDC will gain some due to the lighter reciprocating weight and better aerodynamics in the case at high rpm

I'd be guessing about that exhaust, it seemed a little low to me when you guys first started this thread, so I decided to pull up a chair and see what happened.

I agree on the carb limiting you guys, and would look to alleviate that roadblock first, then decide what to do to the ports after. You could be chasing your tail untill that carb runs clean

Exactly what I was thinkin, chit can that carb before you do any more port work

 

[drf256]

I agree with Mdavlee. On your squish did you cut it flat or angle it?

Angle. But not a matching arc.

 

[Red97]

That may help some. That's a small area to flow through

Matching everything @ BDC will gain some due to the lighter reciprocating weight and better aerodynamics in the case at high rpm

I'd be guessing about that exhaust, it seemed a little low to me when you guys first started this thread, so I decided to pull up a chair and see what happened.

I agree on the carb limiting you guys, and would look to alleviate that roadblock first, then decide what to do to the ports after. You could be chasing your tail untill that carb runs clean

Exactly what I was thinkin, chit can that carb before you do any more port work

Already cut the extension and matched the piston. Mine has the lowest no load rpm.

I am wondering if the ignition timing isn't holding these back just a bit.

 

[Red97]

Joe,

I'm not a carb pro. Not even fair to say I'm a novice.

Maybe @Terry Syd can give us a hand?

In my limited experience, I've found that carbs that are too small are tough to lean out and ones that are too large can't be richened.

I've also seen, first hand, that opening a muffler has caused a saw to need the H needle turned in and not out as one would expect.

I think a stronger vacuum just pulls more fuel out of the nozzle. I've seen Terry Syd's posts where he closes off one H jet and opens the adjustable one.

If we can find a larger Venturi carb, that would be great. I think enlarging the Venturi on this one enough may drop the vacuum signal on its own. I am going to try this first, like Carl did.

I saw 13,550 with no air filter. It was over 13,500. I didn't want to piss rev or lean it too much as it was its maiden voyage.

I broke my intake boot retainer spring. I had to use a traditional 044 clamp on mine.

There's no video, because I ran out of time and daylight, but I had the 20" bar buried in oak and the saw was actually quite good with it.

I'm hoping to get some more footage next Saturday. I'll make an oak block and try to set myself up to do a few before and after shots in the same piece of wood.

I agree, and am in the same boat being a carb novice. I gotta try something. Im Never gonna learn it without screwing a few carbs up.

I agree what you are saying about the small and large carbs.

I think these 14.25 carbs may be just what we need.

 

[mdavlee]

Timing can really limit rpm.

 

[drf256]

Randy says that any timing advance didn't work on the 500p. This saw is basically it's twin mechanically.

 

[Red97]

Timing can really limit rpm.

Randy says that any timing advance didn't work on the 500p. This saw is basically it's twin mechanically.

I'm thinking it is at max advance from factory. But it may benifit for a few * static retard. From what I understand in 2 stroke if you retard the timing, it softens the hit of the powerband, making the powerband broader with more overrev. Just what this saw could use.



Here is how mine ended up.

 

[mdavlee]

You could retard the static and see what it does