The exhaust was around 150º so doesn't need to be changed but the intake was something like 122º so they're going to open that up. I think he said 155º was ideal for that saw.
McCulloch Chain Saws
- Thread starter Bruce Hopf
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Yes ive watched both parts. Waiting on part 3. Im curious of his review on it once its done.
He did say 155° of opening was ideal for a worksaw. Which includes the pm850.
They are going to trim the lower intake a bit and then trim the piston skirt a bit. Pretty interesting
Excited to see how it goes. I'm not really keen on tearing apart my nice running 850 but if it turns into a monster then perhaps I might. Especially if its just a simple port job like that. Transfer work will be another story and annoying the plating is a worry also
Is there video of it?
Btw Jethro I wouldn't worry about messing up the plating in one of those saws too much, unless its peeling off. When I rebuilt the 800 I pretty much plowed into it with my dremel shank and It didn't even scratch it. It was so thick that when I was smoothing out the chip below the intake the abrasive pad had a hard time just breaking down the high edges. I was really surprised that it cleaned up nicely after seeing the original piston smeared that much.
That makes me feel better. I have never run one. I have cut with a stock Stihl 461 and a stock Husky 372. Never felt a reason to buy either or any modern 70cc + saw except the 462 and 500i, and that was due to their weights. I bought an Echo 800 for lending. Tough saw but doesn’t have MAC level performance.
Ron
I have trimmed 1/16” off the skirt on the intake side of one of mine based upon second hand advice attributed to Mastermind. It either didn’t impress me or it was on my one rebuild that cold seized. I will check my cold seized piston and update you.
Ron
The video in mention is the set up and getting the numbers. They havent done the porting or trimming yet. I hope they video the port job too. If not oh well. Atleast they are doing a good job of explaining things.
Good to hear that about the chrome
They're machined to pretty tight tolerances. A very thin layer smeared on the surfaces with a finger tip should do the trick. You just don't want it oozing all over the place inside the case when things get torqued down. Excess can end up in bearings and smearing the piston and cylinder if it heats up enough to get loose.
The knock on those is the poor structural integrity of the mounting locations under long bar use along with injector issues on the 500i. Not sure I'd buy either one for anything longer than a 24" setup.
Thanks! Much appreciated.
There is no hp rating published to answer that. Nobody has built a dyno to test either that ive read about. That would be cool to know though. Rpm i would guess to be around 11,000 give or take. I believe ron may have checked several of the 82cc saws awhile back and found some of them to be around 10-12000rpm. Maybe he will chime in to confirm that.
So I tore the switch apart, cleaned it and put it back together.
Googled bullfrog carb and can say I definetly dont have that. Just your common SDC carb.
After the over night soak in Seamfoam and a few minutes in the US cleaner I threw it all back together. Thankfully I didnt tear the gaskets and diaphragms because I didnt have any rebuild kits.
Threw it all back together and the damn saw actually fired up and ran. It wasnt perfect and I could only tune it with low, but it runs nonetheless.
Just gonna have her sell the saw as running but for parts. Manual boiler was pushing oil everywhere but on the bat I think. It was coming out from under the top front cover. Not gonna investigate. Unfortunately she'll be lucky to get $25 as older saws arent collected much around here.
Thanks for all the help though.
Tore down to the points and coil twice before I realized the switch was shutting the saw off when at full throttle. The vibration was enough to just move the switch. Apparently I didnt bend the brass/copper strip enough for it to hold position.
1st saw Ive ever seen where you had to remove the air filer to make adjustments. Not a good setup IMHO.
Thanks again for the help guys.
They were made to a price really and the extra machine time adds up i suppose. The higher up the ladder the more things you got like rubber on the handle and spikes or sprocket nose bars.
It does make carb removal easier.
Still a dam good buy though back then 40 years later its still got years of firewooding in her
Would get more on ebay for it, especially if you can say it's running. Ladybug sells those for 75-100 all day long, and some of those look like they fell off the back of a truck on a muddy road. I might be interested...
I don't need another project saw, but that never stopped me before. Pretty sure there are some other guys here thinking the same thing. I just rebuilt an SDC last night that is looking for a saw.
Tooo much lol but if ya had to have 1
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