Yay! It's Here!

[promac850]

Looked through it... good info. Gonna have to run to the store to get some stuff soon, like sealer and some dremel bits and accessories, lol. Burned through a grinding stone and four 120 grit sanding drums just to polish up the ports a little and only have a few left.

Gotta eat lunch first... lose my brains if I don't.

 

[promac850]

Well, got back in from porting... I'm 99% done with that now, just have to clean up around the ports where the rings slide past it, so I don't have a grenade in my hands. I'm thinking 220 grit for making that microscopic chamfer. Is that too fine or coarse?

What about "honing" the cylinder with sand paper, what grit do I use and how do I do it?

Also one more thing before to ask for advice on before I can assemble it. How do I remove the carbon deposits in the top of the cylinder? I'm unsure of what to use or how to approach the cleaning of that.

Here are the ports... 99% finished now. Not absolutely perfect, but close enough.

 

[promac850]

Seems like this thread is pretty dry.

 

[dieselsmoke]

People still at work?
Once it's done, you might want to change your NAME!:hmm3grin2orange:

 

[procarbine2k1]

That looks like pretty good work, those 850's are pretty cool saws. Nice avatar by the way, been meaning to tell ya!

 

[promac850]

People still at work?
Once it's done, you might want to change your NAME!:hmm3grin2orange:

Will have to do that... Wonder if Darin would change it? I don't think I can edit my username... with the lowly status as MVP... :msp_lol:

That looks like pretty good work, those 850's are pretty cool saws. Nice avatar by the way, been meaning to tell ya!

Thanks!

 

[homelitejim]

Looking good. I don't have anything to add so just reading along.

 

[briantutt]

Post em like this please!

Looks great! How did you do that so perfectly? Endmill?

 

[promac850]

Looks great! How did you do that so perfectly? Endmill?

Dremel with grinding stone, and a 3/8" wooden dowel with a slit, spinning in a drill at 3000 rpm with 220 grit sandpaper. Works good. Wish I had all that fancy end mill and lathe stuff, but can't afford it, and no room in barn for it, lol.

 

[briantutt]

Dremel with grinding stone, and a 3/8" wooden dowel with a slit, spinning in a drill at 3000 rpm with 220 grit sandpaper. Works good. Wish I had all that fancy end mill and lathe stuff, but can't afford it, and no room in barn for it, lol.

Looks great for dremel work!

 

[promac850]

Looks great for dremel work!

I agree, intake port is beautiful; exhaust, not quite so, lol.

 

[rwoods]

Promac, I can't tell from your pictures nor from Stinkbait's how much of the slope either of you left in the exhaust port on the right side. Did you leave the slope angle the same and just widen the opening uniformly front to back or did you straigthen the angle abit? I assume MAC did it that way to channel the flow to the right. I compared my PM800 port with my PM850 port tonight and noticed for the first time that MAC widened the PM800 (at least on the outside) about the same as you and Stinkbait did, but the slope angle was still prominent.

Also what are your thoughts on the polished intake (Stinkbait did the same) as I thought a little roughness was supposed to better atomize the fuel - is this just a garage legend? Just asking questions as I have zero experience and zero training on this sort of thing. Thanks, Ron

 

[promac850]

Promac, I can't tell from your pictures nor from Stinkbait's how much of the slope either of you left in the exhaust port on the right side. Did you leave the slope angle the same and just widen the opening uniformly front to back or did you straigthen the angle abit? I assume MAC did it that way to channel the flow to the right. I compared my PM800 port with my PM850 port tonight and noticed for the first time that MAC widened the PM800 (at least on the outside) about the same as you and Stinkbait did, but the slope angle was still prominent.

Also what are your thoughts on the polished intake (Stinkbait did the same) as I thought a little roughness was supposed to better atomize the fuel - is this just a garage legend? Just asking questions as I have zero experience and zero training on this sort of thing. Thanks, Ron

I left the slope the same as best I could, and made the port a little wider, as upon closer inspection of the muffler and the port, I realized that McCulloch did make that slope for optimal flow. Since the bend leading to the muffler is fairly tight, I recommend all other people porting theirs to do the same.

As for the intake port, I polished it out of preference, and the belief that the air/fuel mixture is plenty well atomized out of the carb, and especially when it is forced up through the transfers after being drawn into the crankcase. I also forgot to mention that I have yet to match the plastic carb manifold to the port... that will come tomorrow. Since the port is a little bigger all the way around, I want a smooth transition so the air/fuel mix slips right into the crankcase.

 

[heimannm]

pm610 - check you PM's, I found a handle but I lost your address.

Mark

 

[promac850]

Got back in from the barn, and was carefully sanding to make a small bevel on the exhaust port... I can't tell if I made the bevel big enough... help please. :help:

As for the intake, it looks done now. I forgot to take pics of the slightly modified plastic intake manifold. :bang: Will have to post them soon.

Also reassembled the carb, one question about it... does the hole in the throttle plate need to be open? (you can see it's covered by the throttle shaft in the pic)

 

[MnSam]

Yes, I think you are going to want to rotate that plate so that the hole is at about the 11 o'clock position (in the picture). I don't think it would idle properly otherwise.

 

[promac850]

Yes, I think you are going to want to rotate that plate so that the hole is at about the 11 o'clock position (in the picture). I don't think it would idle properly otherwise.

Thanks, will do that. Confirmed my theory that all carbs with a hole in the throttle plate need to be set up so air can go through it.

 

[promac850]

Well, just got back from Autozone. Purchased one item. Indian Head gasket shellac, as heinmannm said it's worked well for him. Couldn't find the Moto Seal that the Pioneer expert recommended. Blue rtv, red rtv and all that other rtv, and none of them seemed to sound as good as Indian Head. I almost bought all of the different Permatex stuff, lol. Just would've cost about 35-40 bucks, but then I could post a pic of them all and ask you guys what to use.

 

[promac850]

I'm back! Was out in the barn working on cleaning a few more parts up, like the clutch, drum, and rim drive. .404 pitch rim drive, so donated chains need to be that pitch. oke:

Okay, next thing I was working on was the tank/carb assembly thing. Since the tank assembly actually is a PM800 part, the blue choke and green oil buttons needed to be switched with the black ones on the PM850 assembly. (850 tank is corroded through the bottom, hence all of this work) Here is a pic...

As for the progress of this project, I estimate it to be at about 40% complete. Pic for you to guess the progress by...

The one, single, lonely item I bought at Autozone... please welcome Indian Head.

 

[Arrowhead]

I use Permatex Ultra Copper for everything, I'm not saying any of the other recommendations are not good (they all will work), just giving you one more option. It seems like it's easier to find than some of the others.

I was looking at your porting pics, did you raise and lower the exhaust?