My MS461 Project

[Freudianfloyd]

I had a different thread about my new to me MS461 before it was mine, but now $150 later, it is mine.

I was told it was straight gassed, but still ran, just didnt have much power. The saw is very clean, and had an almost new 24" bar. After pricing parts, I decided it was worth it to give it a try.

Well today I finally pulled the jug off. I knew the piston was going to be scored, but I didnt expect it to look like this...

However, the rings werent stuck so I had that going for me I guess.

So I called up Stihl, and they had the piston without rings, wrist pin, bearing, or retaining clips, for $89. So I bought a meteor for $38.

Then I crossed my fingers before looking in the cylinder.

Unfortunately, it had lots of aluminum transfer on the intake and exhaust side.

Being the cheapskate I am, and always trying to save parts if possible, I tried my hand at using muriatic acid. And then followed up with 320 grit sandpaper followed by scotch brite.

It's hard to see it, but most of the transfer is gone. But I'm not sure I'm out of the woods.

Most of these are just visible ( especially with a camera flash ) to the eye but smooth, but there are a few that even after sanding like crazy, that I can "feel". Its not really catching my nail, but it has a rougher feel than the rest of the cylinder.

How can I tell if it is more transfer, or if the scratches actually go through the surface?

If it actually went through the surface, I guess I will be on the lookout for a new jug.

Any thoughts?

 

[Freudianfloyd]

Would a hone be a bad idea?

 

[user 122190]

There might some coating in the cylinder that gets removed when sanding. If that is the case then your rebuilt saw will have a short short life. Get an OEM cylinder and be done with it. Sounds like the rest of the saw is like new, so with OEM, you'll have a great new saw at a very low cost.

 

[drf255]

Some more acid on a Qtip can tell you if it’s transfer or not.

How is the plating above the exhaust roof?

A 3 stone hone (make sure the stones are long enough to not grab a port) isn’t the worst thing. Follow with scotchbrite. I use WD40 as lube.

Worst case is you find a used oem jug on the trading post, use the meteor, and be done.

 

[cuinrearview]

What I see in the last pics of the intake side will clean up, but you're not there yet. A "cleaned up" jug will look not that different from a factory fresh one. The cross hatch pattern will look different but close if you're using scotch brite to finish. You can smooth over transfer and carbon smears and make it feel finished, but once that stuff heats up again you'll be right back where you are. As Al alluded to, some pics of the wall above the exhaust port will tell a lot more.

 

[cuinrearview]

That upper transfer port looks like I've been grinding on it.

 

[Freudianfloyd]

I will get back to it later today. It was already 10 pm when I was working on it, and getting cold, so sitting in garage with the doors wide open for ventilation wasn't the most enjoyable thing. Above the ports still shows some marks, but they are smooth. I will assume there is still transfer there though, as the scratches are still visible.

My plan going forward though is: I am going to clean this cylinder up the best I can. I already ordered a Meteor piston, so I am going to start with that and put it and the original cylinder back on. In the meantime, I am going to keep watch for a cheap OEM cylinder to pop up for sale somewhere. Or worst case, I buy a Meteor, or Hyway cylinder kit, which comes with another piston, and rebuild this saw again if this current fix fails.

 

[Czed]

Here's Randy's method

I just use emery cloth on a mandrel
Carefully removing transfer.
Done many many saws.

 

[Freudianfloyd]

Here's Randy's method

I just use emery cloth on a mandrel
Carefully removing transfer.
Done many many saws.

I watched that video last night after I stopped. I was just afraid of going too deep, but he was using much more coarse paper than I was and he didnt have any issues, I'm going to have to try some more. I have until Monday until my piston shows up anyway, might as well take my time.

 

[cuinrearview]

When I got in trouble was when I used too much pressure. You can almost use whatever grit you want if you let the little sand grains do the work.

 

[Freudianfloyd]

When I got in trouble was when I used too much pressure. You can almost use whatever grit you want if you let the little sand grains do the work.

Well everything I've done so far has been by hand. Maybe time to step up to some air tools.

 

[Freudianfloyd]

I think I saved it.

Here is the cylinder after some light honing.

Exhaust side

Intake side

Nearly all scratches are gone, there is one small scratch at the bottom of the intake side that I can feel when I run my nail across, but it doesnt catch. I dont k ow if I should keep honing or if I should leave well enough alone.

 

[Czed]

I think I saved it.

Here is the cylinder after some light honing.

Exhaust side

Intake side

Nearly all scratches are gone, there is one small scratch at the bottom of the intake side that I can feel when I run my nail across, but it doesnt catch. I dont k ow if I should keep honing or if I should leave well enough alone.

Run it

 

[Freudianfloyd]

Run it

I noticed a small speck that I can catch a nail on every once in a while, about .5mm in size. It is below the lowest port on the intake side, so I dont think the rings ever go low enough to make contact with it, but I cant seem to get it to go away with sanding or honing. Hopefully that isnt an issue.

And my piston wont be here until Monday so I have 3 long days of looking at this saw without being able to start it up. The longest 3 days of my life!

 

[TheTone]

I watched that video last night after I stopped. I was just afraid of going too deep, but he was using much more coarse paper than I was and he didnt have any issues, I'm going to have to try some more. I have until Monday until my piston shows up anyway, might as well take my time.

The beauty of the flap method is that the grit takes off the high spots and doesn't dig into the chrome coating. If you were to take that same bit and hold it against the cylinder, you would see a much coarser pattern on the cylinder wall. Hence the admonition to keep it away from the surface and keep it moving. This minimizes your chances of doing damage to the cylinder. I have started with 150 grit using that technique and had no problems. I would not hand sand with anything coarser than 220.

 

[huskihl]

Run it. Looks good as new from here

 

[Freudianfloyd]

This has been a long few days. I have been waiting for the new piston to arrive, and I just got word from my daughter that it is was just delivered. Now I am stuck at work counting down the minutes until I can get home and get this saw running. I went through the saw yesterday and cleaned it up to almost new condition. I still need to pick up a chain, but in the meantime I have a 20" bar I can run.

 

[cuinrearview]

Don't get in a hurry, you'll be tearing it back down...

 

[Freudianfloyd]

Don't get in a hurry, you'll be tearing it back down...

I'm just in a hurry to get to work on it. I have already spent days going through the saw and looking for any other potential issues. In all honesty, my biggest worry is when removing the old c clip from the wrist pin, I can only verify the location of one. The other one shot off when I removed it, and have no idea where it went. I keep fearing it fell in the crankcase, but I have inspected it several times while slowly turning it over, blew air through it, turned it upside down and shook it, and poured gas in the crankcase and swishes it around before dumping it.

I dont think it's in there, I'm 99% sure it isnt in there, but I still worry about it.

As far as putting it back together, I think I will be ok, and will make sure to take my time, and pressure test it before I try starting it up.

 

[trains]

when messing around with piston circlips, pack the crank, or cover it in rags, and some even put a plastic bag over the piston, so if it does try for freedom, you might just catch it.

either way, looking forward to progress reports and pictures.