ms260 build

[thompsoncustom]

hey guys been thinking about getting a ms260 just to tear it apart and build a better saw out of it to replace my current lightweight limbing saw.

Plans so far:
Port
.015 squish
muffler opening/redesign more like the ms660 muffler.
bigger elbow/carb
Timing.

So my questions are around timing and the carb mostly. I see a lot of people running the 044 carb is that the best option? Do you loose the ability to run at fast idle and choke the saw or can that be rigged up somehow? I fell like I could make something for a external choke and live without fast idle if that's the case. I'll probably run the 044 air filter setup and just cut the air filer cover.

Another option is I could bore the venturi on the stock carb if it will allow it and drill out the high speed jet for more fuel but i'm not sure how that would compare to the 044 and the ms260 still has the terrible air filter that would need replaced/modded

As far as timing goes my personal thoughts are because of the increased air and fuel it would be beneficial to increase the timing but with the already increased compression are parts going to start breaking like the rod? Any other downsides other than harder starting? Like piston pitting?

Anything else I'm missing that could add some more power to a project firewood saw? Thanks

 

[slimbo3006]

Following this... I am intersted in this too. I bought a 260 a couple of years ago with plans to build it. when I got it, it ran so well that I didn't feel the need to do anything other than a muffler mod to it. Couldn't even bring myself to tear it down...

For a smaller and limbing saw...I think these are hard to beat.

 

[Wood Doctor]

Seems like it would be easier to find a non-running 026 PRO and rebuild that instead. Maybe not, however, because most 026 PROs keep on running. Like this one:

 

[Mad Professor]

If this is a limber/runner the WT-194 carb is what you want, or WT-426 (compensator carb).

Do squish and Muff mod. MS660 muffler sucks pink Kitty balls. A 066 DP is more like it.

I've not ported 026 or done timing work @pioneerguy600 , knows how to make them run/last.

 

[thompsoncustom]

If this is a limber/runner the WT-194 carb is what you want, or WT-426 (compensator carb).

Do squish and Muff mod. MS660 muffler sucks pink Kitty balls. A 066 DP is more like it.

I've not ported 026 or done timing work @pioneerguy600 , knows how to make them run/last.

my 660 wears a DP that's been opened up and baffle removed so I guess I didn't mean a stock one.

I would probably weld the front closed and put a hole on each side with deflectors. I like the open can design with them coming out the side.

now you want to talk about muffler that suck. the ms290 I rebuilt started off with two little slits that equaled the size of the tip of my pinky. which is one of the reasons that saw melted down in the first place I assume holden all that extra heat. she's a screamer now tho

 

[thompsoncustom]

Well bought a ms260 on facebook from a guy in another state. Saw was rough but price wasn't bad so I figured it would be a good project saw. Sent the guy the money and never got the saw. Just got my money back the other day from paypal and purchased a new Holzfforma 260 instead.

Plans still the same but I might replace some other parts as well like the rings and circlips but i'm gonna put her to the wood hard and see if it holds together.

Think i'm going to do the build in 2 stages.
Port work, gasket delete, muffler mod, wt-194 carb

after the saw is broke in good than i'll move on you stage 2 which will be a 044 carb and intake boot. Along with a custom master control lever.

 

[Mad Professor]

I'd have looked for a rebuildable 026. I'd not put much work into a chi-com clone.

Glad paypal got your refund.

 

[thompsoncustom]

don't blame you there but there's none local as that was my first thought as well.

I've had a couple stihl chainsaws and only one holzfforma so far which is a 660 and it has been a amazing saw I couldn't be happier with it.

 

[thompsoncustom]

well got the blue saw in the other day. put some fuel in it just to make sure it started and cut like it should. can't really comment on stock performance as I have maybe 1 min of run time on it.

tore it down far enough to get stock port timing number.

exhaust 96-97
transfers 121
intake 67

measured squish from the outside with standard solder came in at .045 will get some accurate readings when I lower it

 

[thompsoncustom]

well got the saw back together tonight.

ported the intake, exhaust, and blended the lowers but didn't touch the uppers at this point.

didn't change exhaust timing at all but did increase intake duration a little. both intake and exhaust were widened. intake side was taken .100 to the edge of the skirt exhaust side was .050 from the edge.

removed the baffle from the muffler and opened up the back to match the bigger exhaust port. also made the muffler a dual port with both ports = 100% of the exhaust port on the cylinder side.

squish came in at .018 after gasket delete and some material removed off the bottom of the cylinder.

don't have the wt-194 carb yet but this saw came with a high speed adjustable carb just had to remove the limiter tab.

will get out and do some testing tomm.

 

[thompsoncustom]

Well got out today and did some cutting and i am happy with how it's turned out so far.

With a .325 20in bar buried in the wood I could apply a fair amount of pressure without it bogging down at all.

For a limbing saw it's prefect but I still plan on upgrading carbs, intake boots, and air filters. Just kind of drives me crazy knowing there a lot more potential gains from the porting that it's not using because the intake track is so small.

Got a holzfforma ms460 carb which is what I'm going to modify for this project. Snorkel is going to need to be cut off and a plate made for that, also have a idea to keep the choke fully functional off of the master control lever i'm gonna test out. Air filter is just gonna end up being a velocity stack and a uni most likely.

 

[thompsoncustom]

well it's been awhile since I updated this. got a holzfforma ms460 carb and cut it up to fit inside the plastic. had to cut the high and low speed screws, idle screw, snorkel, bend the fuel and impulse line, and I soldered the throttle plate hole closed.

With the stock filter it idles nice and smooth without the chain running. just changed over to this velocity and knock off k&n 45 degree angled filter today. took it out and just did a couple cuts but it runs a faster rpm now inside and outside the wood. muffler has also been opened up to 150% of the exhaust port but the saw still isn't annoyingly load at all.

tuning getting harder as the rpms are increasing just from the noise and revs its harder to tell where it's at.

i think all I still want to do to this saw is take the cylinder back off and adjust the upper transfers, I was thinking somewhere between 15 and 20 degree blowdown would be better. not 100% sure how intake duration effects everything but the intake port is much taller and bigger than most 026 I've seen stock or ported.

also still running a 20in .325 bar but have a stihl 16in picco bar I will be changing to in the future, mostly for weight but the increasing speed will be nice too.