Stihl 039 Rebuild

[Terry Syd]

That cover is the cover for the European saws, I don't know how it ended up in Oz. I've got the US/Australian cover that vents flat with the crimped outlet.

The European cover goes across to the opposite side where there is a hole in the European muffler. It really is a much better cover to mod than the US/Oz cover. The OP can put a hole on the opposite side of the muffler to take advantage of shape of the cover.

Making the outlet larger is easy. You need to remove the metal below the opening down to the screw, then reshape the cover to enlarge the opening. I'll see if I can find a picture of my muffler.

 

[Terry Syd]

The close up pictures of the muffler have been lost on AS, however there is a picture of the saw in a 'Rat Rod' thread (post #66) - http://www.arboristsite.com/community/threads/the-rat-rod-of-chainsaws.259019/page-4

Maybe you can enlarge the photo to get a better view. I did not drill the center dimple of the muffler as I wanted the saw to be relatively quiet. I did mod the internal baffle so that as soon as the exhaust enters the muffler it can vent to the sides instead of going down the tube (improves the blowdown). That sends the sonic waves bouncing around the muffler before they come out the front and into the lid. The muffler is louder, but has a nicer tone - kinda like 'roooom' rather than 'braaap'.

The part number for the standard/European lid for the muffler is #1127 145 1601

 

[Brewz]

The muffler cover is part of a replacement muffler I bought off ebay.
I modded the original muffler and it worked well but it was very rusty.





I bought the aftermarket muffler and modded it with the additional hole in the baffle face as noise does not worry me...... I always use hearing prothection
My 066 with the front of the baffle removed is louder

I have increased the size of the hole in the aftermarket 039 muffler front..... see below:
I would like to increase the flow more but when cutting dry dusty wood in hot conditions in Australia, we need to be mindful of gas direction as starting a fire is a real possibility if I just drill the face and vent the gas strait forward of the saw. It needs to go the the side full stop.





I also have finer mesh for a replacement spark screen with a much better open area than the OEM stuff. mIne is between 45 and 50% open area which sure helped my 066

I would like to keep the front cover as is and add some sort of vent/vents to one or both sides of the muffler body to help flow. Will need spark screens too.
Anyone have any sugestions on a good way to go about it?

 

[Brewz]

Mmmmmm next problem.
On inspection of the bar while I was cleaning it after the weekends virgin run, it was burnt up a bit on the outside back corners top and bottom closest to the sprocket.
I sat the bar back on, and the center of the removable sprocket ring now sits out further than the center line of the bar. It dont line up any more.
Its like the entire motor is sitting a tad further to the right looking from the back of the saw.

I guess thats the disadvantage of a non pro clamshell saw.

I will be stripping it again to replace the oil seals again before further use and will definitely be making sure the motor is seated further to the left when tensioned down.

Issues like this make me consider selling it and getting a small pro saw to sit beside my 066

 

[singletrack100]

Brewz, I went back to your pics of assembly, and it looked like the clutch drum was not seated inward all the way? Take a look and make sure the slot on the drum mated with the tab for the oil pump. I have an 029 and from what I understand, the 039 is the same, and there is a notch on the drum that if not lined up, would push the drum outward, hence pushing the sprocket outward. Easy to miss lining up sometimes. Just a thought.

Duane

 

[Brewz]

Hi Duane
The slot is lined up, wouldn't get any oil if it wasn't
The culprit is the clutch drum though. On closer inspection, it has done the same on all my bars, just I noticed it more on the new 325 bar that sat closer to the sprocket and spun faster with the 8 pins. It was smoking at WOT. They are all worn on one side of where the chain enters and exits the bar.
It looks like the Oregon Clutch Drum sits out a tad more than a Stihl drum when seated up against the clutch face, just by 1 or 2mm.
A star type clutch drum would fix the problem but I have different bars and chains I use on the saw depending on what I am using it for, so the removable sprocket style is preferable.
I also don't what to go and spend $100 on a new Stihl clutch drum to find it has the same issue.
I suspect the motor is slightly misaligned in the chassis and the factory star sprocket hid the fault.

I am thinking I will place a shim between the chassis and where the bar stud attaches to the motor base to shift it to the left enough to align the chain sprocket with the bar. It wont need much.
Will report back!

 

[Terry Syd]

I had to grind the inside of my 9-pin rim sprocket in order to get it to line up with the bar. I just used the edge of the grinder to create a depression so that the rim sprocket could move closer to the clutch drum.

EDIT: I am also using a NK bar, so the rim sprocket had to move in even more - I still got it to fit.

 

[a. palmer jr.]

I put spur sprockets on all my 290 based Stihl saws, don't want the hassle of trying to get the rim sprockets to fit. I've never had this trouble with other saws, only these.

 

[tickhound93]

I put spur sprockets on all my 290 based Stihl saws, don't want the hassle of trying to get the rim sprockets to fit. I've never had this trouble with other saws, only these.

I've done maybe a dozen of the 1127 series saws with both rim and spur sprockets and have never encountered a bar alignment problem, but this thread will definitely make me pay close attention on the 3 rebuilds I got in the shop.

 

[tickhound93]

I had to grind the inside of my 9-pin rim sprocket in order to get it to line up with the bar. I just used the edge of the grinder to create a depression so that the rim sprocket could move closer to the clutch drum.

EDIT: I am also using a NK bar, so the rim sprocket had to move in even more - I still got it to fit.

You are using a 9 pin sprocket on an 1127 series saw? Either you run a very small skip tooth bar or your wood is very soft... I mean the wood you are cutting with a chainsaw. Or I completely mistook what saw the 9 pin went on. Ha

 

[a. palmer jr.]

I've done maybe a dozen of the 1127 series saws with both rim and spur sprockets and have never encountered a bar alignment problem, but this thread will definitely make me pay close attention on the 3 rebuilds I got in the shop.

I think my main problem was with the sprocket brand. I bought a Chinese sprocket, trying to save a bit of money and the sprocket wouldn't contact the worm drive for the oiler. It stuck out and misaligned the chain but wouldn't work the oiler. The last two I bought were Stens brand sprockets and they fit okay but cost a bit more.

 

[Brewz]

Crappy pic but you can see how the chain slot in the sprocket doesn't line up with the bar slot

So from the comments above, I would be led to believe that this happens now and then on these clamshell saws and I should either get a star sprocket or sell it and buy the nice 036 pro I have found for sale?

 

[tickhound93]

That may be so. I've used power mate sprockets and stihl never had a problem. Have used farmertec sprockets on 1128 series no problem. Could also be a torqueing procedure difference? I always snug the crank pan bolts, then snug the bar stud, then torque the pan bolts and tighten the stud.

 

[huskihl]

I don't think there's "that" much room for the motor to be misaligned. Are you certain that everything is installed properly from (and including ) the oil pump out?

 

[tickhound93]

I don't think there's "that" much room for the motor to be misaligned. Are you certain that everything is installed properly from (and including ) the oil pump out?

I agree after closer examination of the picture I would say that is not an engine alignment issue. Something in the sprocket/oiler configuration is definitely off. Go back to OEM even if they are worn out and report back. If you can't find OEM reasonable hit me up, I will send them your way (good used) in exchange for some of your Australian monopoly play money for shipping. Or I will just send them to you free because I have no idea how to accept money through the interweb.

 

[huskihl]

I'm thinking there's a washer behind something that's supposed to be in front of it. Idk

 

[tickhound93]

Now this is not gospel but on these saws installation is as such.
Oil pump is bolted on
Next goes worm gear, I always rotate it clockwise until it seats.
Oil pump washer with Top pointing out.
Whoah this is an edit I forgot the clutch! D'oh!!
Clutch bearing
Cluth drum
Sprocket
Sprocket washer
E clip.
Check those things too.
Now I'm not remembering if there actually is a worm gear washer??...

 

[a. palmer jr.]

I'm thinking there's a washer behind something that's supposed to be in front of it. Idk

Or a concave washer put on backwards..

 

[Brewz]

Yes its all installed properly. The clutch pulls up on the shoulder on the crank shaft.

I just went and measured the Oregon clutch drum compared to the old Stihl Star sprocket that the saw came with, and its just under 2mm higher around the center which pushes the sprocket over out of alignment with the bar.

Pic:

 

[tickhound93]

Problem solved. Good job and great use of tangible numbers.
This thread is fantastic for new saw wrenchers.
Now. You need a stihl rim sprocket clutch drum. Do you have one?
Also I wouldn't be so quick to sell of an 039 for an 036... Get your 039 right and cut with that sob.
In the meantime I'm still on the prowl for an 036 builder.. To replace my... Ms390 lol