044 rebuild

[blsnelling]

Probably due to cleaning up the scored cylinder. I doubt you'll see any further trouble.

 

[frogdaddy]

Probably due to cleaning up the scored cylinder. I doubt you'll see any further trouble.

Very possible. I thought he put a new cylinder on it until I went back and reread the thread.

 

[NHRA1877]

Thanks, could the muffler bolts just have loosened up? The saw was running rich and 4 stroking in the cut as I didn't want to be lean at all when breaking it in.

The way the crank bearings went in: I tried a way that has been listed on this site of installing on the crank then heating the case, the install didn't go as easy as explained and the bearing only went in slightly into the case, when I pulled on the crank to pull the crank/bearing out the bearing soaked enough heat that the crank slipped out ok the bearing. From there I removed the oil pump and tapped the outer race of the bearing with a slight tap and the bearing came out. Reinstalled oil pump heated the case and dropped the clutch bearing in the traditional way, it soaked the heat and the crank dropped right in, heated the flywheel case half with the bearing on the crank already and the half slid right on. Tightened the case halfs and it took a good couple whacks to get the crank to free but it freed up and spun very nice.

 

[MustangMike]

I put locktite on all the bolts except the chain guard. When I didn't lost the two lower muffler cover bolts in no time.

 

[NHRA1877]

As long as them loosening is not a rare case and it happens on some saws, especially old bolts, I will just throw some lock washers on. The saw sounds fine and there doesn't seem to be any grinding or odd sounds, tomorrow I will pull the flywheel, clutch and plug and spin the crank to see how the bearings feel.

 

[old-cat]

NO lock washers! The screws are supposed to be serrated, I think that's the right word. They grip right under the head. If your screws are smooth under the head, you've got the wrong screws.
You still might have to lock tite them in. I NEVER have any problem with them loosening, myself.

 

[Adirondackstihl]

NO lock washers! The screws are supposed to be serrated, I think that's the right word. They grip right under the head. If your screws are smooth under the head, you've got the wrong screws.
You still might have to lock tite them in. I NEVER have any problem with them loosening, myself.

X2

 

[blsnelling]

I've never had problems with Stihl's serrated bolts backing out. You must net be getting them tight enough.

 

[NHRA1877]

Ok, so I pulled the clutch and flywheel off and felt the bearings as best I could, there doesn't seem to be any grinding or rough spots. I did however find this. What would cause this?

I'm more looking to find out what the cause would be and not so much a reply of "bearings are bad". What about the bearings being installed wrong would cause this if that's what is wrong?

The oil pump was in the saw when the bearing was seated, so I don't see how the bearing could be installed too far out towards the clutch if the oil pump stops the bearing? Could the old oil pump have anything to do with it?

 

[NHRA1877]

Any ideas?

 

[blsnelling]

Is that an OEM worm gear?

 

[NHRA1877]

Yes it is

 

[griffonks]

I wonder if the pto bearing has spun in the journal and is moving on the crank?

 

[NHRA1877]

I don't see how that would happen unless the bearing itself was locked up. Also I don't know how that would melt or rub the worm gear but I could be wrong. I'm not trying to second guess anyone, please don't get me wrong, I'm just trying to learn.

Well I guess it's going to feel like forever till I know the true full reason, today after the discovery of what happened I was frustrated/mad/cautious so I fast forwarded the process, I was going to be sending the saw to mastermind after 2-5 tanks of fuel but it's currently in transit to TN for a port and hopefully he can let me know what's wrong with this saw :-(

 

[splitpost]

bit hard to tell from your pics but it looks like the bush is in backwards dunno,but something is not right with the way it went together,that oiler gear looks like its been tightend up against something with a hex,the clutch spider would be the only explanation ,did you fit the scatter shield between the clutch and oiler gear?

 

[griffonks]

I ran into a problem with my first MS440 (I bought it and 2 044's), the handle was broken and the compression was slightly low, 140 psi. I went in to ring it and found this:

Both the piston ring locating pins had snapped off, scoring the cylinder. No heat evidence, clean piston top, just a bad Stihl piston.

 

[splitpost]

got some serious varnish going on in that cyl

 

[griffonks]

I bought it two weeks ago as a kicker for the saw I wanted, a 576xp. I put that picture up because it showed the two locating pin divots, but there's light coming in through a red plastic ball I put in the intake manifold to keep junk out while I was cleaning the saw. There's some transfer of course. Here's a better pic without the red light... Sorry for hijacking the OP's thread.

I have repaired and rebuilt a bunch of Husqvarnas and a bunch of homeowner Stihls, but only one Stihl pro saw an 026. I have never seen an OEM piston do this. I know that one of the circlips was in incorrectly. The ends were in the grab notch on the slug, so maybe some body was in there or it was a bad day on the Stihl factory line. The rings were in the correct alignment.

Oh heck, it doesn't make any sense....

 

[Adirondackstihl]

Any ideas?

Both myself and trx250r180 have had the same issue.



Has a lot to do with how you seated your bearing!

 

[blsnelling]

The oil pump is the stop for the bearing. It can't physically be any closer than that. So, how can his bearing installation method have anything to do with this?