modded my first saw....the 262xp

[husky455rancher]

well i been on vacation and earlier i was bored and felt like playin with the 262. so i got a bit of direction from a very well respected member here on porting. so i followed his direction and did a mild port, nothing crazy as i didnt want to hurt performance. i didnt swap out the base gaskit to get higher compression but i may get one at some point. while i was at it i modded the muffler. i just bought a 5/8diam steel spacer 1/2" id. simply drilled the hole and mig welded it in. looks pretty good i was gonna paint it up but i had no high heat paint.

anyway i readjusted the carb to where it just 4 strokes at wot under no load. also played with the idle and l screw a bit to get them where they needed to be according to madsens.
after that i buried the 20" bar in a big hunk o maple. i didnt time any cuts before and after or anything but it definatly pulls harder than i did. also it seems to rev up quite a bit faster than before the port work.

i remember years back when i had my 4 wheeler ported the throttle response was incredable. so i guess it gaining revs so much faster means i did ok on the port job.

i cant see any drawbacks to any of the work, well the mufflers louder if anyonje considers that a drawback.

heres a couple pics of the muffler. sorry no pics of the port work. i just took the pic of the muffler cuse if i didnt people would complain about no pics lol.

after doing this i wanted to do the 346 a bit but i think i only got a tank and a half of gas through it, so shes gonna have to wait a bit.

 

[Banshee]

Too bad you didn't do any timed cuts. It would have been nice to see the differance.
When I have my 261 converted to a 262. I'm going to port it and mufler modd it too, plus advance the timing.
I can't wait. Sure wish I could give your 262 a spin.

 

[scotclayshooter]

Damn you beat me to it! i have the jug done just going to do a little polishing to the exhaust port.
I need a 0.012" gasket for mine to have 0.020" squish.
But i might just have access to a lathe so a 12 thou pop up may just happen

 

[Moss Man]

Nice job! I wonder if my 272XP would benefit from those mods?

 

[scotclayshooter]

Nice job! I wonder if my 272XP would benefit from those mods?

Yep it sure would!

Just pop over to youtube and do a few searches.

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[husky455rancher]

i didnt check what my squish was i need to pickup some more solder. hopefully next weekend i can get some time on it to get more of a feel of the difference. i checked the compression too and it still blew a 155

i cant wait to cut into the 346 but i should wait till the warrenty is over

 

[scotclayshooter]

i didnt check what my squish was i need to pickup some more solder. hopefully next weekend i can get some time on it to get more of a feel of the difference. i checked the compression too and it still blew a 155

i cant wait to cut into the 346 but i should wait till the warrenty is over

Yep it took me 3 lots of solder to find one thick enough to check the squish! mine was 0.041"
I got a shock as i was told they were tight from the factroy!

 

[Cliff R]

It really helps to get a baseline on the saws performance before modifications, so you can make direct comparisons.

Any "felt" evaluations can be flawed some, as simply making a saw louder with a muffler mod will often make the operator believe that the engine now makes more power, when in some cases it may not.

In most cases, if the modifications were minor, and you didn't open up the ports top and bottom, just widen and smooth them out some, the saw will not loose any power or cutting speed. Even with that said, keep in mind that making ports larger can have diminshing returns. Port size determines air velocity, and slowing down the air speed can cause shifts in power, or loss of power at lower rpm's, even though it may make more power at high rpm's. There are always comprimises with these things. Best to take "baby steps" with engine mods unless you have some very specific guidance from someone who's been very successful at it.

Porting can quickly take a really nice running saw and turn it into a pile of crap. There is an art to those things, and those who have been successful with porting didn't get there by not messing up a few jugs here and there.

We've got a complete stock 262XP here, and it is a BEAST in stock form with an 18" bar and 3/8" full chisel chain. I wouldn't even consider modifying it in any area simply for firewood cutting. We can completely bury the 18" bar in most any hardwood and the engine stays right up to speed. It would be a very difficult saw to evaluate any modifications to, without a stopwatch.....Cliff

 

[TimberMcPherson]

I often wonder about the real HP gains with some of the mods done.

In bike racing I was in a team that at one point were all running nearly identical 2 stroke bikes. We would try various mods such as gutting the mufflers and think we had made a gain when it came to putting it against a bike it had been previously dead equal to, it was in fact slower.

I have no doubt that major gains are made in many cases, but am always a bit skeptical as louder always seems faster, even when its not.

 

[Cliff R]

Good question. I am in the business, it's just fast cars instead of saws, but we do build high performance stuff for a living. I can say with the upmost certainty, most vehicles are SLOWER after many performance modifications than they were before they were touched.

In my business, we call it "seat of the pants" evaluations. In many cases, modifications that shift power, or concentrate power into a narrower rpm range, do NOT always result in improved overall vehicle performance (at least not without other changes).

2 stroke chain saw engines and cutting speed and potential are not that much different. In any and all cases, we really do NOT know if the modifications were successful unless we set a "baseline" for the performance of the saw BEFORE we make changes.

My intent is not to put a big black cloud over the thread in question. I read Brad's threads all the time with great interest. He shows the rpm potential of the engine before modifications, and the cutting speed, timed. He comes back in later with specifics and more timed results. We can clearly see if, when, and how much the modifications actually helped cutting speed and performance.

I only took specific interest in this thread since I own a 262XP saw. It is in perfect shape, and PLENTY of saw for the current 18" bar set-up. It rips through hardwood without a whimper, and easily stays right up in the upper rpm range with the entire bar buried with pretty heavy load applied. Throttle response is nothing less than fantastic, as is cutting power clear across the loaded rpm range. I'm sitting here asking myself, if I did a muffler mod, or some minor porting, and came out with a louder saw and went after an 10-12" log, I wouldn't have a CLUE as to how much quicker it would get through it without a stopwatch comparison?.......Cliff

 

[Moss Man]

From rancher455's original post, it appeared like he had a mentor guiding him through the mild port job and that he didn't go into this blindly. I agree that a baseline being set would nail down results better, but even then all conditions would need to be the same including chain sharpness and climate conditions.

 

[Cliff R]

Also keep in mind that the 262XP is a strong runner right to start with, making excellent power right out of the box, with plenty of rpms, broad power curve and chain speed to go with it.

When you are working with an engine that already has a very high performance level, making it "better" at any level becomes more difficult than a relatively "low" performance saw with a low compression ratio and choked up exhaust system (for example). In any case, this can make performance enhancments, or at least the results of them become increasingly more difficult to evaluate.

I agree that the work here probably had no negative effects, seems well thought out, but I'd still LOVE to see some stopwatch test results back to back, before and after the modifications, even better after each modification.....Cliff

 

[Cadenhill]

I just received another 261 I purchased and was shocked to see what great shape it was in. I had everything here to convert but this one really ran strong. I put a new three shoe clutch on it and a ported 262 muffler and it runs with the 262's. I doubled checked to make sure it was a 261 piston.
Whoever had this saw really took care of it. I'm going to leave it like it is.
I have enough 262's for all my helpers to run this year. I'm still itching for a 361 though and would like to see how they compare.

 

[Banshee]

I often wonder about the real HP gains with some of the mods done.

In bike racing I was in a team that at one point were all running nearly identical 2 stroke bikes. We would try various mods such as gutting the mufflers and think we had made a gain when it came to putting it against a bike it had been previously dead equal to, it was in fact slower.

I have no doubt that major gains are made in many cases, but am always a bit skeptical as louder always seems faster, even when its not.

You probably already know, but for those who may not.
The mufflers on a bike and mufflers on a chainsaw are two different animals.
The bike works with sound waves to help pull exhaust gases and push back charged air/fuel mixture right before the piston closes the cylinder.
That's why they are shaped like they are to help "funnel air back and forth"
It has to have back pressure because sound waves travel more consistent in a pressurized chamber.
The exhaust on a bike helps control when a bike comes into it's power band.
Lower rpm's mean longer sound waves, so the expansion cambers are longer to assure the sound waves have the length they need to return to the exhaust port at the correct time.
Higher rpm's mean short sound waves, so the expansion chambers are shorter.

 

[woodyman]

well i been on vacation and earlier i was bored and felt like playin with the 262. so i got a bit of direction from a very well respected member here on porting. so i followed his direction and did a mild port, nothing crazy as i didnt want to hurt performance. i didnt swap out the base gaskit to get higher compression but i may get one at some point. while i was at it i modded the muffler. i just bought a 5/8diam steel spacer 1/2" id. simply drilled the hole and mig welded it in. looks pretty good i was gonna paint it up but i had no high heat paint.

anyway i readjusted the carb to where it just 4 strokes at wot under no load. also played with the idle and l screw a bit to get them where they needed to be according to madsens.
after that i buried the 20" bar in a big hunk o maple. i didnt time any cuts before and after or anything but it definatly pulls harder than i did. also it seems to rev up quite a bit faster than before the port work.

i remember years back when i had my 4 wheeler ported the throttle response was incredable. so i guess it gaining revs so much faster means i did ok on the port job.

i cant see any drawbacks to any of the work, well the mufflers louder if anyonje considers that a drawback.

heres a couple pics of the muffler. sorry no pics of the port work. i just took the pic of the muffler cuse if i didnt people would complain about no pics lol.

after doing this i wanted to do the 346 a bit but i think i only got a tank and a half of gas through it, so shes gonna have to wait a bit.

When you did your port job did you cut into the cylinder and raise the exhaust port and lower the intake port or just open up and clean the ports to the cylinder?I am getting ready to do my 026 and am just gathering all the info I can before I start.I found a couple pics of a 026 cylinder by GypoLogger I think that shows the intake and exhaust work he did from the outside but no pics of the inside work(I think I typed in 026 cylinder pics in the search function).Pics are nice,if I see something I can copy it.

 

[husky455rancher]

well if i had to do it again i would have timed the cuts. i didnt do the muffler mod first, what i actually did was the port job put it all back together, tuned the carb and tried it out. so the gain wasnt felf simply by added noise.
after that i did the muffler mod and honestly i couldnt feel the difference in the muffler mod after i did the port work. but when you build motors for hp all the little things add up to the real gains.

i agree the ass dyno isnt the best but im a pessimistic person most of the time when it comes to hp gains. ive build 2 stroke 4 wheelers, my camaro and my charger motors. when i do this type of stuff i usually go into it thinking im not going to see any difference and if so its going to be menial at best. in other words im not the type of guy who says i added octane booster and ran royal purple in my charger and gained a half second.


i did agree that me not timing the cuts puts any gains i may or may not have gotten in a gray area but it is what it is. i have yet to put any real run time on the saw since then. im hoping next weekend i can get a couple tanks through it.

i was impressed with this saw in stock form but im one that believes any engine can be improved upon in some way or another, its just a question of how far you want to take it.

 

[Cliff R]

"agree the ass dyno isnt the best but im a pessimistic person most of the time when it comes to hp gains. ive build 2 stroke 4 wheelers, my camaro and my charger motors. when i do this type of stuff i usually go into it thinking im not going to see any difference and if so its going to be menial at best."

I can say one thing for certain, NEVER trust your "seat of the pants" meter when it comes to making a car fast, and I'm a bit skeptical about trusting it to evaluate a chainsaw as well.

I built/own/drive a low 11 second pump gas GTO, runs 11.30's at 120mph in full street trim on 89 octane fuel. The car is DEADLY consistant, and we've won quite a few fast street car, bracket, and Pontiac only meets with it. Couple of years ago I tested a half a dozen intake manifolds, basically everything available that would fit under the hood without cutting a hole in it.

I was absolutely certain that every single one of the intakes I tested was going to run quicker at the track compared to my "stock" cast iron intake (ported a bit). The strong "rush" of power in the upper mid-range and top end that each of the aftermarket intakes tested provided during a street test had me easily convinced my car was going to be faster everyplace at the track......WRONG. The iron intake ran the best ET of all intakes tested, and only one aftermarket intake ran more mph.

There is something to be said for parts that produce strong "locomotive" type power over a broad rpm range, compared to parts that narrow up the power curve and concentrate it into a narrow rpm range.

Ya, I know it's not a chain saw, but without a timed test, it is VERY difficult to accurately measure "felt" results......FWIW......Cliff

 

[SawTroll]

Also keep in mind that the 262XP is a strong runner right to start with, making excellent power right out of the box, with plenty of rpms, broad power curve and chain speed to go with it. ...

:agree2: Yup, pretty hot-rodded from the factory, so not the best candidate for mods.

 

[Moss Man]

Rancher455, you might as well give that 262xp to me and I'll detune it and give it a good home.

 

[scotclayshooter]

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Stock

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Ported by Timberworlf