HELP! Help with first time porting Echo 800P

[dthieme]

Hello everyone, new member here. I haven’t yet read through the forum, but judging by the many pages of info, looks like there’s a lot of knowledgeable members. I’ve always loved chainsaws, but in the last month I found myself falling down the rabbit hole of porting. I recently acquired my first Echo saw - a very lightly used CS-800P. It seems to be very well built, but it doesn’t get on the pipe quite like my old Stihl 066. I’d like to try my hand at porting the saw and looking for some advice from people who have experience with this or similar models. I should preface this by saying my knowledge of porting and 2 stroke theory is still rudimentary, but I’m happy and eager to learn.

I opened the saw up this weekend. From my limited experience, the exhaust port seems small or narrow at the very least. The bridged upper transfers looked to be on the small side as well. The carburetor is tiny compared to my other big saws and not sure how I feel about the air filter setup. Lastly, the piston design is different than any of my other saws. It is a tall, full-skirt, two-ring, domed top piston. I don’t have the exact timing numbers with me (on my lunch break at work now) but I believe they were 106-EXH, 128-TFR, 146-INT and .040” squish clearance without the base gasket.

I have an idea what I’d like to do, but I’m also the kinda guy that can get carried away trying too much and doing more harm than good. For starters, I plan on doing a muffler mod and machining the base to tighten up the squish. I’d also like to fit an automotive style air filter on this saw (open to suggestions if anyone has some) and make a high top cover or use the existing cover and make a spacer. Depending on how the rest of the saw turns out, I might consider an 8T sprocket and a bar adapter on to run my Stihl bars.

So here is where I’m looking for advice from those of you with experience on building these Echos into a reliable “woods” or “work” ported saw. What modifications have yielded the biggest differences for you? What port timing numbers have any of you used and does anyone have pictures of their port jobs? I realize numbers aren’t everything, but this would give me a place to start. I’m assuming I’ll be raising the exhaust especially after machining the base to tighten the squish. Does it help to widen the exhaust a touch? What, if any, work have you done to the intake port? Are there any benefits to lunged intakes like on my Stihl 056?

For the lower transfers, do you typically just widen them to match the width of the piston window or does it also help to grind and shape the bottom of the transfers to flow better out of the case? I’m nervous about touching the upper transfers, but with the exhaust roof already so low, will I need to raise the uppers at all? At what point is it risking too much blowdown? With the transfers being bridged, would it help to widen them on the intake side?

Would it pay to look for a larger Walbro HDA series or similar carb? If so, will I need to make new linkages? How about changing ignition timing? Has anyone found a piston that swaps in this saw and performs better? Looks like a 281xp has the same bore and wrist pin diameter but the compression height and overall height is quite a bit different.

Lastly, I have a general porting question: at what point does it make more sense to raise/lower ports vs machining the piston? For example, when does it make more sense to machine the piston top vs machining the squish band, raising the exhaust, or raising the uppers. Likewise with machining the skirt vs lowering the intake? Do larger port cross sections hurt you in some instances because you’re sacrificing velocity?

Sorry for the long post, but I greatly appreciate any help and advice I can get and I’m excited to be a member of my first ever forum!

 

[FergusonTO35]

Welcome, friend. You may want to reach out to Kris at S&S Worksaws, he is a member here. Kris did a woods port and increased compression on my CS-500P and it turned out fantastic. He was doing a limited number of these for free + shipping cost to gain experience and get his name out there, maybe he still is doing that or could at least advise you on what to do. Here is the thread on it:

Thread 'Saw rebuild and/or porting. Apply within'

Jun 10, 2024

Good evening everyone.
Some of you may know me, most probably not. For the ones that don't know me, I have a small saw shop based out of a detached shop on my property. As of right now it's something I do in the evenings and weekends. I do a lot of rebuilds from the bare cases up. I also do cylinder machining, porting, custom muffler mods, timing advanced, oil pump mods, and other odds and ends stuff. Up to this point i have kept busy with local loggers in my area and have flipped a lot of saws I have gone through on eBay.
When it comes to the porting aspect I have dabbled in it for...

• S&S_Work_Saws
• Replies: 115
• Forum: Wanted: Builder/Porter

• 

 

[dthieme]

Welcome, friend. You may want to reach out to Kris at S&S Worksaws, he is a member here. Kris did a woods port and increased compression on my CS-500P and it turned out fantastic. He was doing a limited number of these for free + shipping cost to gain experience and get his name out there, maybe he still is doing that or could at least advise you on what to do. Here is the thread on it:

Thread 'Saw rebuild and/or porting. Apply within'

Jun 10, 2024

Good evening everyone.
Some of you may know me, most probably not. For the ones that don't know me, I have a small saw shop based out of a detached shop on my property. As of right now it's something I do in the evenings and weekends. I do a lot of rebuilds from the bare cases up. I also do cylinder machining, porting, custom muffler mods, timing advanced, oil pump mods, and other odds and ends stuff. Up to this point i have kept busy with local loggers in my area and have flipped a lot of saws I have gone through on eBay.
When it comes to the porting aspect I have dabbled in it for...

• S&S_Work_Saws
• Replies: 115
• Forum: Wanted: Builder/Porter

• 

Awesome, thanks for the tip!

 

[FergusonTO35]

You got it. Keep us updated on how it turns out. Also, member Mainer_in_AK has a lot of experience with the big Echoes, I don't know if he mods them but he has certainly rebuilt a lot of them.

 

[Woodpecker]

@Stump Shot @Mastermind @huskihl @farminkarman

 

[Shane¹]

@Stump Shot @Mastermind @huskihl @farminkarman

@srcarr52 too

 

[farminkarman]

Hello everyone, new member here. I haven’t yet read through the forum, but judging by the many pages of info, looks like there’s a lot of knowledgeable members. I’ve always loved chainsaws, but in the last month I found myself falling down the rabbit hole of porting. I recently acquired my first Echo saw - a very lightly used CS-800P. It seems to be very well built, but it doesn’t get on the pipe quite like my old Stihl 066. I’d like to try my hand at porting the saw and looking for some advice from people who have experience with this or similar models. I should preface this by saying my knowledge of porting and 2 stroke theory is still rudimentary, but I’m happy and eager to learn.

I opened the saw up this weekend. From my limited experience, the exhaust port seems small or narrow at the very least. The bridged upper transfers looked to be on the small side as well. The carburetor is tiny compared to my other big saws and not sure how I feel about the air filter setup. Lastly, the piston design is different than any of my other saws. It is a tall, full-skirt, two-ring, domed top piston. I don’t have the exact timing numbers with me (on my lunch break at work now) but I believe they were 106-EXH, 128-TFR, 146-INT and .040” squish clearance without the base gasket.

I have an idea what I’d like to do, but I’m also the kinda guy that can get carried away trying too much and doing more harm than good. For starters, I plan on doing a muffler mod and machining the base to tighten up the squish. I’d also like to fit an automotive style air filter on this saw (open to suggestions if anyone has some) and make a high top cover or use the existing cover and make a spacer. Depending on how the rest of the saw turns out, I might consider an 8T sprocket and a bar adapter on to run my Stihl bars.

So here is where I’m looking for advice from those of you with experience on building these Echos into a reliable “woods” or “work” ported saw. What modifications have yielded the biggest differences for you? What port timing numbers have any of you used and does anyone have pictures of their port jobs? I realize numbers aren’t everything, but this would give me a place to start. I’m assuming I’ll be raising the exhaust especially after machining the base to tighten the squish. Does it help to widen the exhaust a touch? What, if any, work have you done to the intake port? Are there any benefits to lunged intakes like on my Stihl 056?

For the lower transfers, do you typically just widen them to match the width of the piston window or does it also help to grind and shape the bottom of the transfers to flow better out of the case? I’m nervous about touching the upper transfers, but with the exhaust roof already so low, will I need to raise the uppers at all? At what point is it risking too much blowdown? With the transfers being bridged, would it help to widen them on the intake side?

Would it pay to look for a larger Walbro HDA series or similar carb? If so, will I need to make new linkages? How about changing ignition timing? Has anyone found a piston that swaps in this saw and performs better? Looks like a 281xp has the same bore and wrist pin diameter but the compression height and overall height is quite a bit different.

Lastly, I have a general porting question: at what point does it make more sense to raise/lower ports vs machining the piston? For example, when does it make more sense to machine the piston top vs machining the squish band, raising the exhaust, or raising the uppers. Likewise with machining the skirt vs lowering the intake? Do larger port cross sections hurt you in some instances because you’re sacrificing velocity?

Sorry for the long post, but I greatly appreciate any help and advice I can get and I’m excited to be a member of my first ever forum!

I've never ported a cs800p, so I don't have any specific info to share. I can make some suggestions though. For starting out, don't get carried away thinking about huge muffler mods or carbs & air filters. You can always mess with that later. Now, for the timing numbers you posted, the exhaust at 106 and transfers at 128 make sense. The intake at 146 does not, so I would double check that...I would think it would be somewhere between 70 and 80. Some Echo cylinders don't have much meat above the exhaust port window to allow raising the exhaust very much...not sure if the 800 is like that or not, so check. If the piston/ cylinder will allow for widening the exhaust to 65% of the bore diameter, that is what I usually shoot for. Sometimes ring pins, or piston skirts will not allow you to go that wide. Now for numbers....what do you want the saw to do? Do you want it to still run like a tractor, or do you want it to have some more zip? If you want the saw to still be a tractor, I would try raising the exhaust back up to 103-104 after machine work. If you want the saw to turn more rpm with a shorter bar, then maybe more in the 98-100 degree range. Depending on how wide you can make the exhaust would help decide how much blowdown to use. If you can hit 65% of the bore, then you could try 18-20 degrees of blowdown. If you are stuck at closer to 60%, then you might need to increase blowdown a few more degrees. Not knowing what the limitations are on the 800, I would guess that a decent starting point could be 101, 120, 78. As for your question on machining piston vs. raising ports, don't machine the piston. Machining the edges of the piston will eliminate "squish" in that area. Some folks don't like trimming the piston skirt to increase intake duration. Most of the time I don't do it, unless I am going to have to otherwise lower the intake floor a bunch to hit the number I want.

 

[Hinerman]

@Stump Shot @Mastermind @huskihl @farminkarman

@srcarr52 too

@Red97

He ported an Echo 800/8000 that is very impressive

 

[Mastermind]

Thread 'Mastermind Meets The Echo 800P'

May 2, 2016

Here we go fellers. A saw I've never done before.......that's pretty rare these days. lol

The Echo 800P

81cc

52mm Bore

38mm Stroke

• Mastermind
• Replies: 209
• Forum: Chainsaws

• 

 

[farminkarman]

Thread 'Mastermind Meets The Echo 800P'

May 2, 2016

Here we go fellers. A saw I've never done before.......that's pretty rare these days. lol

The Echo 800P

81cc

52mm Bore

38mm Stroke

• Mastermind
• Replies: 209
• Forum: Chainsaws

• 

Excellent!

 

[dangerousatom]

.040 for the squish seems thick to me ( not that Ive worked an ECO ) Id measure the piston gap with no gasket use the old solder on the piston to be sure what the gap is at TDC. Youll have to machine the the cylinder to take anything out after a gasket delete to lower it because of the lip that goes into the bottom end. IMO for now Id just smooth everything out, on the in and out sides of the cylinder,. Take out any abrupt corners, bottle necks, and obstructions in the intake path. Give the muffler a good opening up, particularly if there's a baffle inside the muffler body. Just that bit of tinkering will net you some good gains. If you truly feel the throttle is holding things back you can port the butterfly bar and screw. It doesn't seem like much but that +5% opening the TB up will help with high end RPM.

Post up some pics of both sides of the cylinder with a caliper/micrometer on the sides and somebody will be able to say how much you can take out of the sides. Just from looking at things online there looks to be alot of room on the outside exhaust. Even if you dont take alot out of the cylinder exhaust opening, widening the outer opening and matching that to the muffler opening will help.

 

[farminkarman]

.040 for the squish seems thick to me ( not that Ive worked an ECO ) Id measure the piston gap with no gasket use the old solder on the piston to be sure what the gap is at TDC. Youll have to machine the the cylinder to take anything out after a gasket delete to lower it because of the lip that goes into the bottom end. IMO for now Id just smooth everything out, on the in and out sides of the cylinder,. Take out any abrupt corners, bottle necks, and obstructions in the intake path. Give the muffler a good opening up, particularly if there's a baffle inside the muffler body. Just that bit of tinkering will net you some good gains. If you truly feel the throttle is holding things back you can port the butterfly bar and screw. It doesn't seem like much but that +5% opening the TB up will help with high end RPM.

Post up some pics of both sides of the cylinder with a caliper/micrometer on the sides and somebody will be able to say how much you can take out of the sides. Just from looking at things online there looks to be alot of room on the outside exhaust. Even if you dont take alot out of the cylinder exhaust opening, widening the outer opening and matching that to the muffler opening will help.

0.040” is actually pretty tight squish compared to what I have found on other Echo saws.

 

[mainer_in_ak]

0.040” is actually pretty tight squish compared to what I have found on other Echo saws.

Yep it works fine. CS 800p or the CS 8000 isn't a real valuable or competitive saw compared to the stihls and husqs. So makes a great candidate for a woodsporting home job.

.040 thou squish, slightly widening/raising the exauhst port a sliver still gives about 160 psi. Ignition timing advance makes up the rest.

The piston windows don't match the lower transfers, so a little work there helps big time.

Besides power improvements:

Spikes are too small to safely control the saw when cuting down stumps. Handle is too small diameter for the weight and power of the darn thing. Both cheap/easy fixes.

That goofy flapper filter and stir-stick sized carburetor are the biggest things holding back these rugged cinder blocks. Both cheap and easy fixes:

Thread 'What yer cheap saw favorites?'

Jul 21, 2025

Whats your cheap saw fix?

I like runnin and wrenching on the grey cs 6700's cs 670's and cs 8000's. Quality Made in Japan parts are readily available from scores of online vendors and the saws are cheap.

They cut good, really wake up with basic mods, are easy to work on and have filthy good oilers. Manual oilers too. The round automotive style filters flow well and never let in dust.

Unlimited coils on all and ive never seen one fail.

I've milled with em and cut lots of firewood. The cs 8000 even made it's way on a paid job last year, where I had to plunge cut 32" diameter leaning...

• mainer_in_ak
• Replies: 30
• Forum: Chainsaws

• 

dthiem,
Let me know if you'd like an HDA 45 carb. I have extras. Good luck dude!

 

[huskihl]

Hard to do without the proper tools, but I would raise the upper transfers a bunch more than I raised the exhaust. I’ve never done an 800, but generally speaking, 100–102 on the exhaust, and 18–20° blowdown if you can get 60–65% of the bore on the exhaust width.

In my experience, if you raise and widen the exhaust a bunch without raising the upper transfers, you’ll end up with a saw that might free rev 14K, but in 80 cc size wood you’ll be lucky if you have the torque to turn more RPMs than stock

 

[Mastermind]

Hard to do without the proper tools, but I would raise the upper transfers a bunch more than I raised the exhaust. I’ve never done an 800, but generally speaking, 100–102 on the exhaust, and 18–20° blowdown if you can get 60–65% of the bore on the exhaust width.

In my experience, if you raise and widen the exhaust a bunch without raising the upper transfers, you’ll end up with a saw that might free rev 14K, but in 80 cc size wood you’ll be lucky if you have the torque to turn more RPMs than stock

Bingo.

 

[srcarr52]

I took 0.030" from the squish band when I did this 800P, then I had to raise the transfers 0.125" to get the transfer duration I wanted.
The numbers I landed on in duration are 158 ex, 119 tr, 156 in and I thinned the throttle shafts shafts and opened up the venturi some on the carb.