My 026 project

[jeremyc]

Hey guys, first post here. I have been a member/lurker here for a while and have learned and answered many questions by searching this site. I have a mild case of CAD like most around here =D.
Figured I would share my latest purchase. Found this 026 on Craigslist last week for $80- not the cheapest deal but a really clean saw. Bought it from the original owner, he said he bought it new and cut 1-2 cords of firewood a year. The piston and cylinder are scored due to a lean condition. Has a brand new stihl wt194 carb and the rest of the saw is in great shape. I did a pressure and vacuum test on it and all seems healthy so i'm guessing the failure was due to carb settings or a gummed up carb previously. It came powerhead only because he wanted the bar/chains for his replacement saw.
I thought it was strange that the top cover has a hole and plug for compression release.?

I have torn it down and started cleaning the cylinder to prep it for a new meteor piston. With a timing advance, muffler mod, and maybe some minor exhaust port work it should wake up nicely!
Planning to get a narrow kerf .325 16 inch bar/chain and running a 8 pin sprocket on it for limbing and smaller cutting with speed. Thoughts and opinions on sprocket size for that b&c setup on this saw?

 

[jeremyc]

Started working the cylinder with acid a little bit.

 

[Wood Doctor]

Jeremyc said. "I thought it was strange that the top cover has a hole and plug for compression release.?"
--------------------------------
That top cover was designed for the 026 PRO, which has a decomp valve that the 026 never had. If you change out the top end, you can convert this to an 026 PRO. I think you did OK for $80. Good luck on your restoration. It's always a challenge. Here's one of my 026 PRO's that runs flawlessly:

 

[jeremyc]

Yeah I knew the Pro came with the decomp but I didn’t know the non pro model came with the same top cover.

Doing some reading about 026 mods and it sounds like removing the base gasket sets the squish too low on the 44mm saws. What are you guys using for a thinner gasket to tighten the squish without machining the cylinder base? I will have to wait until my new meteor piston arrives to measure this particular one, but I’m reading that a base gasket delete usually puts it around 0.008-0.010? Which can cause some contact issues.
Thoughts and opinions are welcome for the mods. I am planning to do whatever I can to squeeze some power out of this thing. Probably widen the exhaust port some too while I have the cylinder off.

 

[Wood Doctor]

"Yeah, I knew the Pro came with the decomp but I didn’t know the non pro model came with the same top cover." ------------------------
The Stihl 026 shroud never had a hole for the decomp valve. That shroud cover you have is not the original. I doubt any of the orange plastic on that saw is the original. But, it does look nice.

Best thing for you to do is get the saw running first before modifying it to death.

 

[jeremyc]

After doing some searching it seems like others have the same setup with the top cover with the plug in the hole. It all looks Oem and the guy I bought the saw from has no reason to lie on the history of the saw but you never really know. . He was heartbroken to have to sell it.

 

[brock1994]

Check if it has an adjustable oiler. If so it is the pro version. I just picked up the same saw and it had the same deal. Plugged decomp as Well. Not really a necessity on this small 49cc saw. Nice grab btw!

Brock

 

[brock1994]

Not all the pictures loaded. After looking it appears it does have the adjustable oiler. So based off that i would say it's the pro version.

Brock

 

[Tinman204]

That's a nice saw you got there! Looks to be in great shape..

I just rebuilt my ms260 pro yesterday that had a similar lean condition and piston scoring. Mine was a bad diaphragm in the carb causing the lean condition.

The guy I got my new piston from was there helping me do the build. He had an identical 026 like yours that has the hole in the top cover but no decomp valve.

His had a black rubber plug filling the hole. I suspect yours is missing.

We compared my 260 to his 026 and it seems if you don't have the decomp you have the smaller bore. With a decomp and it's the larger bore (44.7mm).

If you are going to rebuild that saw you should maybe get an 026/260 pro P/C and go from there. Never hurts to have a bit more displacement.

I did simple muffler mod and rebuilt the carb on mine and it rips pretty good for a 50cc saw.

I may take it back down and do some porting on the cylinder but I figured I'd get it running perfect before I do any modding.

And its funny but my saw has the pro piston and cylinder from factory and the hole for the adjustable oiler BUT it doesnt have the adjustable oiler.

 

[jeremyc]

I will post better pictures soon. It does not have the adjustable Oiler even though the bottom of the saw has the hole for it, the cylinder does not have a compression release hole, just the plastic cover has the provision for it but it is capped with an OEM rubber plug. I am certain this is a non pro model but just had never seen one with that top cover.

 

[kr5258]

Many variations of the 026/ms260. See Tech Info below for serial number intro of the new style cylinder cover / compensating carb.

 

[drf255]

Lots of wrong info here.

That’s a later model non-pro 026, before the changeover to the MS260 model.

Both plastic and metal badge covers did come with the decomp hole, the metal ones being rarer. I’m not sure if the plastic badged saws ever came without a decomp hole, same with the MS260’s.

Stihl has a PN for the plug that goes in the hole. The Non-pro has a plugged decomp hole and the non adjustable oiler.

The 024/024S and very early 026 came without the case relief for the adjustable oiler. Later cases came with the notch, but not always with the adjustable oiler.

The non adjustable oiler was metal on the 024 and early 026, then it became plastic. The adjustable was always metal.

So you’ve got a late model non-pro 026 that looks original to me. Yes, the squish should be .008 without a gasket. The 50cc (44.7mm) 260’s run base gasket delete at around .017 squish.

Aluminum Roof flashing is generally .010 and is thin enough to cut and use a paper punch on for the bolt holes. Coat it with some gas safe sealant for the install. That is what I did before I started porting them fully. Here’s one of mine pulling a 36” bar. The owner asked for the video.

 

[jeremyc]

Wow thanks for the clear information @drf255 and @kr5258. That aligns with what I have read in other threads.
@drf255 I am assuming that 026 you have there is running a full woods port job? Thats pretty impressive! is that skip chain or full comp?

 

[drf255]

Full comp (I believe-vid old)

Yes, full port job and making around 5 hp.

You have the old style back, so non comp carb. Comp carb covers have lever and not a knob on the rear.

 

[drf255]

A few more. 36 noodling, 25" full comp and 16" realistic bar.

 

[jeremyc]

Wow. I know mine wont run like that when I'm done with it but that sure looks fun.

 

[brock1994]

That ported 026 is a little ripper!

I've been pretty confused with all the differences in the 026s. I know the pros have the decomp and adj. Oiler but how they used the same case with the hole for the oiler and same cover with the decomp threw me off.

Thanks for enlightening me as I would have never known but now I do.

Brock

 

[jeremyc]

Cleaned the cylinder a little more. I think it’s about ready for the new piston. Replacing the starter rope at the moment and then need to make my custom base gasket.

 

[John Lyngdal]

I run a 16" .325" bar with a 8 pin sprocket on one of my 026 saws, actually a MS260. Really handy combination and it's the first saw I look at when going out to cut wood.

 

[brock1994]

Cleaned the cylinder a little more. I think it’s about ready for the new piston. Replacing the starter rope at the moment and then need to make my custom base gasket.

Is that the finish product of the cleaning? It looks like there is still transfer and the new rings might not seat correctly.