Stihl 026 rebuild

[MattG]

For what it's worth, I got my wife to record me doing some cuts and a tiny bit of "piss-revving". When I listened to the clips later - i.e. not live with the saw so close, I could hear things a bit better. My hearing ain't what it used to be.

http://www.arboristsite.com/community/threads/help-needed-tuning-ms200t-h-side.291913

Well, it helped me!

 

[bikemike]

Yeah my hear isn't so great either. Once you pin point what your listing for then things will be easier in the future

 

[MattG]

Ok, stock spring is back in the WT-394
As soon as the WT-194 shows up from the states, I will pull them both apart and compare their internals.



Mate, may I ask you to elaborate of a couple of points from the above just so I fully understand what your talking about?
When you say you set the carb to the highest idle RPM then richen till bog goes away, I am interested in your method of achieving highest RPM and exactly what you mean by that. There is a great carb tuning vid on youtube where the bloke tunes an MS460 to 3300 rpm with the LA, leans it to get to max RPM's then dials back to 3300 RPM again with the LA. He then richens it out to 2800 rpm idle speed which is what I tried to do today.



I am interested in your tuning procedure details, and anyone else's, to add more knowledge to this thread !

Also, this being my first ported saw, and first saw under 64cc, I am having trouble working out when it starts to 4 stroke from the tone.
My other saws are easy to tell as there is a clear change in note from the high clean 2 stroke whine to when the rougher burble kicks in, but with the 026, it gets the high clean 2 stroke whine at between 15000 and 16000 RPM, and as I richen it out, the revs drop but I cant really detect that rough burble I am used to listening for.
What should I be listening for to indicate where I should set my WOT speed?

Lastly...... I have no idea what "piss revving" means

Yes, I've watched that vid a couple of times - it's pretty useful - and lots of service manuals prescribe similar methods for other stihl equipment. I'm no expert (just a software guy ) and after watching a few folk, I use a simpler method - which I think is the same as the drf255 way - and I think achieves the same result as the guy in the youtube vid.

1. tune with LA for half decent idle
2. turn the L counter clock wise to get to it rich then....
3. then turn L clock wise (lean) listening for it rising to a maximum
4. then you turn it back (I think it's about 1/16 - 1/4 turn) counter clock wise (rich) till it sounds really stable (i.e. it doesnt slowly decrease or "load up" overly rich)
5. you can repeat steps 1. to 4. to fine tune etc.

Terry - who I believe is a bit of a whizz kid on carbys might be able to actually explain what's actually happening here - hope he does - I'd love to learn the theory. Like I said, I'm no expert .

 

[Terry Syd]

Whizz kid? Crikey, it recently took me three months to find a leaking welch plug - one that I had put in!

The different ways to set the idle works well on Zamas as their idle mixture is a separate circuit from the low speed circuit. However, when you are working with the Walbros, you are also tweaking the low speed circuit every time you adjust the L needle.

What Brewz was trying to do was blend in the L and H circuits to get the best powerband. After reaching that goal, then he can go back and tweak the idle and transition with the spring and idle adjustment. - Without touching the L screw that has already been set for the best power.

 

[Brewz]

Ha ha
In my profession, you only need to be able to spell guru to be one

 

[MattG]

Whizz kid? Crikey, it recently took me three months to find a leaking welch plug - one that I had put in!

The different ways to set the idle works well on Zamas as their idle mixture is a separate circuit from the low speed circuit. However, when you are working with the Walbros, you are also tweaking the low speed circuit every time you adjust the L needle.

What Brewz was trying to do was blend in the L and H circuits to get the best powerband. After reaching that goal, then he can go back and tweak the idle and transition with the spring and idle adjustment. - Without touching the L screw that has already been set for the best power.

Only joking, sport!

Anyway, I always wondered what the science to setting the mixture around idle with the L screw was. My laymans guess is that you richen it off from the fastest rpm point, so that although you got slightly lower speed at idle, you've got extra juice for a responsive throttle blip.

(By the way it's first thing in the morning in the UK now, freezing cold, hope you aussies are enjoying your summer!)

 

[Terry Syd]

You have to remember that the factories are restrained by EPA guidelines. Thus, the carbs (airbleed/transition holes, springs, jets) are set up to work within those guidelines. When the factories set the idle, they are doing it with the EPA designed carb. You have to think outside that EPA box in order to improve performance.

I've actually got the wood fire going in my stove at the moment. Yesterday I had the air conditioner on...

 

[MattG]

I've actually got the wood fire going in my stove at the moment. Yesterday I had the air conditioner on...

Woo... real up and down stuff...

 

[Terry Syd]

I remember the first time I experienced a 'cool change' in Oz. The temperature was 42C and humid, just awful. I went into an office building for a meeting and while there the fellow said as he looked out the window "looks like the cool change arrived". When I left the building a half hour later, the temperature had dropped to 21C. Bloody amazing...

 

[MattG]

I remember the first time I experienced a 'cool change' in Oz. The temperature was 42C and humid, just awful. I went into an office building for a meeting and while there the fellow said as he looked out the window "looks like the cool change arrived". When I left the building a half hour later, the temperature had dropped to 21C. Bloody amazing...

You certainly are in a land of extremes there Terry... I'd certainly rather have the 21C.
(Anyway I have psyc myself up to get ready to change CV joint on wifeys car - I hope the temp here rises soon! )

 

[drf255]

This is my latest 026 build.

I'm putting an 026 jug on an old 024 Super. The oldest I've ever encountered.

http://This is SPAM/threads/west-german-024-super.346/

"This is SPAM" is the other forums name. Unfortunately, the name is censored here so that "This is SPAM" appears instead of its name.

I don't get it.

O P E F o r u m . C o m

 

[drf255]

I don't feel like reposting all the pics, that's all.

I'm still a member here in good standing.

 

[Brewz]

I remember the first time I experienced a 'cool change' in Oz. The temperature was 42C and humid, just awful. I went into an office building for a meeting and while there the fellow said as he looked out the window "looks like the cool change arrived". When I left the building a half hour later, the temperature had dropped to 21C. Bloody amazing...

Yeah it did that here on Thursday.
I was driving home and my car said it was between 40 and 42 deg c all the way home (1 hr drive) at 6pm. Humidity waqs through the roof and it was just sweat central.
Got home and the air con was on, had something to eat and a couple beers.
Noticed it was getting windy outside so I went out on the balcony to check it out.
Within 2 minutes it was torrential rain and about 19 deg c
Literally 120 seconds and it was cooler out than in with the air conditioning on.

Dont start me on the dust storms I encountered when I lived in the red center of Aus........ I have seen it rain red mud balls! And we were driving in it.

I love this country....... if its not trying to bite, sting, poison, cook or kill you, its not in Australia!

 

[MattG]

to eat and a couple beers

priorities lad, priorities...

 

[Brewz]

Tuned the 026 today with the stock spring back in the WT-394 carb.

I can now stall it lean and rich at idle and got a sweet tune at 2800 RPM with very good throttle response.
Would it out lean and brought it back till it started to burble.
Repeated this a couple times to get an ear for the sound. Its still a clean scream but revs have come down and there is a bit of a crackle in the note.
This gave me 14750 RPM

Cant wait to get it back into some timber!

 

[Brewz]

Wound the tune out today to see how it would go while I was doing some other tests on another saw.
Its a little power house but made sooooo much noodle that it couldn't clear it from the sprocket cover

I will like the 3 takes it took to get a clean cut, eventually dropping revs back to 14700 in the 3rd video.
I also tried to hold the saw out from the timber to let noodles coming out the top front of the sprocket cover clear, but the wood came loose and started to rock and move on me.

Will try and line something better up one day soon

 

[Brewz]

And What do you know....... the wife just found a package at the front door with a WT-194 carb in it

 

[MattG]

Wound the tune out today to see how it would go while I was doing some other tests on another saw.
Its a little power house but made sooooo much noodle that it couldn't clear it from the sprocket cover

I will like the 3 takes it took to get a clean cut, eventually dropping revs back to 14700 in the 3rd video.
I also tried to hold the saw out from the timber to let noodles coming out the top front of the sprocket cover clear, but the wood came loose and started to rock and move on me.

Will try and line something better up one day soon

Just seen it - it sounds nice. Sure does clog up fast though! Looks like you got spaghetti for tea....

 

[Brewz]

Take 2

 

[Brewz]

Take 3........ bloody noodles