Echo 4910/501p “shortcomings”

[Woodpecker]

Should probably have mentioned mines not ported. It’s my ground saw meant for unskilled hammer donkeys.

 

[Dolkitafreak]

Should probably have mentioned mines not ported. It’s my ground saw meant for unskilled hammer donkeys.

Then I agree, in stock form they don’t have the nuts for 3/8! Honestly even stock they do ok with 20” .325.

 

[srcarr52]

Then I agree, in stock form they don’t have the nuts for 3/8! Honestly even stock they do ok with 20” .325.

I was honestly surprised how well it did pull 3/8's stock. Not something a novice could run efficiently but it pulled it ok and it was easy to keep from stuffing it.

 

[Duane(Pa)]

The blue lines are torque. I think that splains some of these little feller’s personalities

 

[Red97]

View attachment 330402
The blue lines are torque. I think that splains some of these little feller’s personalities

Have a chance to run yours yet?

 

[Duane(Pa)]

Have a chance to run yours yet?

Yes. You did a great job! I think it gains a little with each tank. I may swap in an 8 pin one of these days just to see if there's anything to be gained. Nice and light! That's a "thing" for me

 

[FergusonTO35]

View attachment 330402
The blue lines are torque. I think that splains some of these little feller’s personalities

Makes sense. My Echoes have good low end grunt but none are screamers. Which is the opposite of what you would expect from a Japanese engine!

 

[ammoaddict]

View attachment 330402
The blue lines are torque. I think that splains some of these little feller’s personalities

I'm not sure how to read this graph. Never seen one before.

Sent from my moto g(7) power using Tapatalk

 

[Woodpecker]

Makes sense. My Echoes have good low end grunt but none are screamers. Which is the opposite of what you would expect from a Japanese engine!

I’m thinking lower rpm and higher torque fits with Echo’s philosophy of building durable ope. I like that.

 

[Duane(Pa)]

I'm not sure how to read this graph. Never seen one before.

Sent from my moto g(7) power using Tapatalk

Well, the torque isn’t quantified in the graph. What you do see is that it’s a fairly flat line which doesn’t drop suddenly as the rpm comes down.

 

[Battle Cross 2]

Yes. You did a great job! I think it gains a little with each tank. I may swap in an 8 pin one of these days just to see if there's anything to be gained. Nice and light! That's a "thing" for me

Light weight is a thing for me also. I run 14" 3/8lp cause I wanted a quick handling limbing saw. With all the talk of these things liking the .325 I might have to do some testing.

 

[Ketchup]

Can anyone tell me stroke length on these puppies? 30mm?

 

[farminkarman]

Can anyone tell me stroke length on these puppies? 30mm?

Well, the bore is 44mm, so methinks it is 33mm.

 

[farminkarman]

Alright, here is your confirmation on 33mm:

 

[farminkarman]

.040 from the band and 106-7 on the exhaust. I didn’t figure I could keep the walls and roof straight without going through at 104

On the 4910 I just did, the exhaust was 115 after cutting 0.040" from the base (no squish band cut). I wanted to get it up to 105, but I stopped at 108 because I was worried about blowing through the roof. Here are the numbers I had after cutting the base with before & after porting:

After machine work:

Ex: 115
Primary Trans: 130
Secondary Trans: 135
In: 80

After porting:

Ex: 108
Primary Trans: 124
Secondary Trans: 127
In: 80

I didn't mess with ignition timing, but I did do a muffler mod and some minor carb work. This build generated 5.19 peak hp with a pretty flat torque curve from 10K on down. As @Red97 previously mentioned, it would be interesting to try a 490 piston to allow a wider exhaust.

Edit: I'll add that when I raised the secondaries, I flattened the roof to a more normal slope about 1/4" in from the plating.

 

[Woodpecker]

Seems like a gooder place to drop a link to this video:

 

[Dolkitafreak]

On the 4910 I just did, the exhaust was 115 after cutting 0.040" from the base (no squish band cut). I wanted to get it up to 105, but I stopped at 108 because I was worried about blowing through the roof. Here are the numbers I had after cutting the base with before & after porting:

After machine work:

Ex: 115
Primary Trans: 130
Secondary Trans: 135
In: 80

After porting:

Ex: 108
Primary Trans: 124
Secondary Trans: 127
In: 80

I didn't mess with ignition timing, but I did do a muffler mod and some minor carb work. This build generated 5.19 peak hp with a pretty flat torque curve from 10K on down. As @Red97 previously mentioned, it would be interesting to try a 490 piston to allow a wider exhaust.

Edit: I'll add that when I raised the secondaries, I flattened the roof to a more normal slope about 1/4" in from the plating.

Any video of the saw? 108 is lots lower than I’ve done, 5.19 is a great result! I’d like to see how it cuts.

love these saws

 

[farminkarman]

Any video of the saw? 108 is lots lower than I’ve done, 5.19 is a great result! I’d like to see how it cuts.

love these saws

I don't have any video of it. When I finished the saw it went straight to Joe for a dyno run before heading to @sawmikaze. I think the lower exhaust would have done even better if I could have widened the exhaust more. Not sure how folks are getting such high exhaust roofs if doing any machine work....maybe there is some variation in the jugs?

 

[huskihl]

I don't have any video of it. When I finished the saw it went straight to Joe for a dyno run before heading to @sawmikaze. I think the lower exhaust would have done even better if I could have widened the exhaust more. Not sure how folks are getting such high exhaust roofs if doing any machine work....maybe there is some variation in the jugs?

Only way I can see doing it any higher than that is in an hourglass or bell shape.

 

[Red97]

Yeh, just raise at the cylinder wall. And drop back down into the exhaust port.