Miller Mod Saws and the Echo CS-500P

[fordf150]

OK so i checked into the 500p and 490
First thing is that the 490 has only been out for a few months and Echo has already put a serial break in the parts I dont know why they insist on changing stuff so much.

Cylinder on the 490 and 500 is the same $99
piston is the same $66.83
crankcase assembly is different...not sure what that is but maybe it has something to do with the chain tensioner changing
both saws come with a walbro wt-1009 carb that has a 13.5mm venturi....just for reference a dolmar 5105 has a zama c1q with a 13.5mm venturi

 

[quotedraven]

My 500 has been bulletproof. I just modded the muffler and it does all that is needed. Great all around limbing saw.

 

[MillerModSaws]

From the perspective of coming up with porting numbers and shaping ports, is there a difference in how you come up with a formula for a particular saw if you know in advance that a saw is being ported to increase short-bar versus long-bar performance?

For this saw, for example, would you approach it differently if it was being built to only ever run say 13"/.325"/8t versus only 20"/.325"/7t versus a variety of bar/chain/sprocket combos?

Yes and no. I do port them different for different users. I do not make logger saw as hot as I do a wood cutters. More rounded corners, little less comp, etc. And usually a lower exhaust as most of them like there power down low.

 

[MillerModSaws]

What is your thoughts on the domed pistons? I am not a fan of popups....right or wrong i always thought a flat top piston promoted a better flame front than a popup but seems like echo uses allot of domed pistons in their saws and while they dont have the hinderance of the popup i still wonder if flat wouldnt be better. any chance of an easy piston swap to get a flat top so that the squish can be cut square? of maybe mill off the dome? piston thick enough for that idea? i doubt it as most of the flat tops are pretty thin in the center and i bet these are no different. seen a few of them with holes punched through from using metal piston stops

I think the 590/600/620 all use domed pistons and i have replaced rings on quite a few echo trimmers that ran a domed piston

Maybe a domed piston doesnt effect transfer flow as badly as a popup since its still a smooth transition and is actually directing the flow up into the chamber

The dome is only 2.5mm thick. So won't be not cutting it flat. However pistion swap well its could happen but for s work saw I believe for the most part the parts should be left oem.

 

[MillerModSaws]

OK so i checked into the 500p and 490
First thing is that the 490 has only been out for a few months and Echo has already put a serial break in the parts I dont know why they insist on changing stuff so much.

Cylinder on the 490 and 500 is the same $99
piston is the same $66.83
crankcase assembly is different...not sure what that is but maybe it has something to do with the chain tensioner changing
both saws come with a walbro wt-1009 carb that has a 13.5mm venturi....just for reference a dolmar 5105 has a zama c1q with a 13.5mm venturi

Thank you!

 

[quotedraven]

This saw came out a while ago and masterminds thread was way more convincing that I needed a port job.

 

[fordf150]

The dome is only 2.5mm thick. So won't be not cutting it flat. However pistion swap well its could happen but for s work saw I believe for the most part the parts should be left oem.

I understand that as well. 5 or 10 yrs from now when that saw needs a new piston, being able to go to the local dealer and buy one off the shelf and install it is important to allot of people including me. i was just brainstorming on ways to end up with a flat top piston. domed pistons cant be real easy to get good numbers out of...the normal way of marking the cylinder is push a ring in with the piston but a domed piston holds the ring up slightly from the true edge of the piston. since i just had that idea...how in the world do you get a good mark on the cylinder wall with domed pistons???

 

[fordf150]

This saw came out a while ago and masterminds thread was way more convincing that I needed a port job.

did randy do one of these? i remember him doing a 5000 or something similar...back when echo's were grey in color. he called it the 346 killer.

 

[quotedraven]

did randy do one of these? i remember him doing a 5000 or something similar...back when echo's were grey in color. he called it the 346 killer.

Yes he did he has shinier pics search it

 

[MillerModSaws]

I understand that as well. 5 or 10 yrs from now when that saw needs a new piston, being able to go to the local dealer and buy one off the shelf and install it is important to allot of people including me. i was just brainstorming on ways to end up with a flat top piston. domed pistons cant be real easy to get good numbers out of...the normal way of marking the cylinder is push a ring in with the piston but a domed piston holds the ring up slightly from the true edge of the piston. since i just had that idea...how in the world do you get a good mark on the cylinder wall with domed pistons???

I get it and there a very easy pistion. I would bet there's a flat top replacement that's close. When finding your numbers your correct. You just have to keep good notes. I still use the ring but double check everything with the flashlight. So you port it with a ring and record both variables. Fortuntently this dome isn't real agressive so your numbers arnt off that far.

 

[fordf150]

Yes he did he has shinier pics search it

will look it up sometime. thanks.

 

[rburg]

Randy did a 520 echo that was gray that was mentioned as a 346 killer.

 

[blsnelling]

What is your thoughts on the domed pistons? I am not a fan of popups....right or wrong i always thought a flat top piston promoted a better flame front than a popup but seems like echo uses allot of domed pistons in their saws and while they dont have the hinderance of the popup i still wonder if flat wouldnt be better. any chance of an easy piston swap to get a flat top so that the squish can be cut square? of maybe mill off the dome? piston thick enough for that idea? i doubt it as most of the flat tops are pretty thin in the center and i bet these are no different. seen a few of them with holes punched through from using metal piston stops

I think the 590/600/620 all use domed pistons and i have replaced rings on quite a few echo trimmers that ran a domed piston

Maybe a domed piston doesnt effect transfer flow as badly as a popup since its still a smooth transition and is actually directing the flow up into the chamber

One of the possible issues I see with cutting the squishband is how much you have to raise the transfers. I don't have enough evidence to support this theory, but I wonder if it's not a hindrance to performance. I recently saw this mentioned by someone else, and it's something I've wondered about as well.

 

[Sam_choq]

Projection of the air more in intake side or exhaust side by de transfer port can change anything ? evacu more burning air in sucking fresh air

 

[Idahonative]

did randy do one of these? i remember him doing a 5000 or something similar...back when echo's were grey in color. he called it the 346 killer.

http://www.arboristsite.com/community/threads/mastermind-meets-the-echo-cs500p.188048/#post-3337250

Stock:


Ported:

 

[Chris-PA]

Stock number!
Squish .043"
Comp 170
Exhaust 120 (duration = 120)
Trans 131 (duration = 98)
Intake 70 at big opening 82 at point.

Now we get a glimpse of how Echo is dealing with emissions. I recently measured the timing on a pre-strato Poulan and it had strange numbers too, but different from this - except for the short blowdown. I have an idea what that's about and have been considering making a thread on it. I'll have to ponder these numbers.

That looks to be a Walbro WT carb? Do you have the model number or know the venturi diameter?

This is what I mean when I write about strato being a performance enhancement. Those numbers cannot be optimum for power, and that WT is not going to compare to the intake opening area of a typical strato.

Last, I think that tapered intake may be intended to reduce spit back. While a nice flat opening is good for power because it uncovers area very fast as the port opens, it creates a very strong pressure wave as it opens and closes. I've wondered why the factory intakes don't seem to be flat.

 

[fordf150]

Now we get a glimpse of how Echo is dealing with emissions. I recently measured the timing on a pre-strato Poulan and it had strange numbers too, but different from this - except for the short blowdown. I have an idea what that's about and have been considering making a thread on it. I'll have to ponder these numbers.

That looks to be a Walbro WT carb? Do you have the model number or know the venturi diameter?

This is what I mean when I write about strato being a performance enhancement. Those numbers cannot be optimum for power, and that WT is not going to compare to the intake opening area of a typical strato.

Last, I think that tapered intake may be intended to reduce spit back. While a nice flat opening is good for power because it uncovers area very fast as the port opens, it creates a very strong pressure wave as it opens and closes. I've wondered why that factory intakes don't seem to be flat.

Wt-1009 13.5mm venturi

 

[Chris-PA]

Wt-1009 13.5mm venturi

Thanks - that's the biggest and I figured that's what would be on it. For reference, my 40cc Husqvarna 142 has the same size carb stock. It may be a bit of a bottleneck in this build.

 

[fordf150]

Thanks - that's the biggest and I figured that's what would be on it. For reference, my 40cc Husqvarna 142 has the same size carb stock. It may be a bit of a bottleneck in this build.

Idk... Dolly 5105 is a zama c1q 13.5mm and it is top of the 50cc class for out of the box torque. Of course a small carb helps the bottom end and there have been reports that the 5105 respond well to a larger carb

 

[bikemike]

OK so i checked into the 500p and 490
First thing is that the 490 has only been out for a few months and Echo has already put a serial break in the parts I dont know why they insist on changing stuff so much.

Cylinder on the 490 and 500 is the same $99
piston is the same $66.83
crankcase assembly is different...not sure what that is but maybe it has something to do with the chain tensioner changing
both saws come with a walbro wt-1009 carb that has a 13.5mm venturi....just for reference a dolmar 5105 has a zama c1q with a 13.5mm venturi

Wow that's a small carb. My husky 136 36cc has a walbro wt540 with .530" 13.4 something mm venturi punch the venturi out a bit to drop a bigger test carb on it