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Although they are not definitive, here are photos of the muffler side of SP105 and SP125 blocks.

169018d1295492884-dscn2024-jpg


169017d1295492874-sp125-pieces-jpg


Mark
 
Most likely is a CP block. It is sleeved. That's okay with me. I can now see honing marks striaght out from the ex. port, but up in the compression heights, are concentric marks, I believe from the piston rocking. The stroke is definitely 123cc. But the piston is so sloppy either the block was bored .030 and a stock piston was put in, or the block is stock with an SP105 piston which would still be .030 off.

We'll see what happens.
 
It's okay. The wind is gone from my sails, but the sun comes up tomorrow. This is an "opportunity". Probably going to wind up being my first full resto McCulloch when its over. Kinda tough to feel the history talking from a cobbled together mess.
 
All is not lost. Its a great feeling to take those saws all the way down, fix what is wrong and what ever the previous owner screwed up. I havnt had a yellow saw yet that hasnt had to come down to every last bolt. Gives you an intemant knowledge of the saw and its inner workings.
 
why mcculuch ?

Mark, I started to leave a smart alec post about your bar being on upside down on that big MAC in the forefront of your group shot but thought someone on that thread might think I meant it. Nice picture. Ron
 
Busmech said:
I may be wrong but I've never seen a 125 with a bridged exhaust but then I've never seen a CP opened up. All of the SPs Cs that I have have a more oval port with no bridge.

I type too slow
Click to expand...

cpr said:
Most likely is a CP block. It is sleeved. That's okay with me. I can now see honing marks striaght out from the ex. port, but up in the compression heights, are concentric marks, I believe from the piston rocking. The stroke is definitely 123cc. But the piston is so sloppy either the block was bored .030 and a stock piston was put in, or the block is stock with an SP105 piston which would still be .030 off.

We'll see what happens.
Click to expand...

I just checked my CP125 and they do have a bridged exhaust.
 
promac610 said:
Thought I'd post pics of my Pro Mac 610... I recently installed a set of bucking spikes... enjoy! :) Also, what is the biggest bar I can run on this saw? I'm thinking a 24" bar is as big as it can pull. Someone please fill me in on that.

View attachment 169056
View attachment 169057
View attachment 169058
Click to expand...

Nice to have a 24, but saw will be happiest with a 18, 20. For something to buck the big stuff, they work pretty good. Don't ask me to carry one any distance.
 
cpr said:
SP125 came today. Looks very clean, bore and piston look good, but compression is only 95psi. Not complaining, just trying to figure it out.

1. Could the piston be hitting the schrader valve on my tester at TDC and not giving a true reading?

2. Decomp replaced with a bolt. Leak source?

3. Popsicle stick bore check seems to indicate stock bore and it is an unpainted, unnumbered block which I would guess is a replacement and would not have been bored. But if it indeed had been and reassembled with the wrong piston... I hope this isn't the case. This new job doesn't give me time to be tearing into a saw at that level.

Anyway, what do you guys think? I don't want to start it until I figure this out.
Click to expand...

Brian13 said:
Does the cylinder look like it was freshly honed. Maybe the rings are wore out, and it just needs a re-ring.
Click to expand...

Brian13 said:
Do the SP125s have pinned pistons or are the rings free floating. Can you maneuver a ring end to see the gap.
Click to expand...

leeha said:
How doe's the piston, cylinder look through the exhaust port.
I have seen many sp125's with unpainted blocks. It could very
well be original. The rings could be stuck in the piston grooves,
or just plain ole wore out.
I would say you will most likely be taking it appart.


Lee
Click to expand...

cpr said:
Thanks Brian, how DO you do that?

Yeah that's the way it was listed alright.

I checked around a little more. Piston has a slight dent on the crown over between ports. I've seen much worse on here, I don't think that's the problem. The piston will rock quite a bit on the pin when you roll it slowly through compression. No satisfying little chuff when it breaks over tdc. Not sure the piston should move that much on the pin center line when I poke it with a popsicle stick through the plug hole.

Anyway, I'm done looking at it. I'm not going within a foot of it until I hear back from the seller. I'm keeping it, but it's not worth what I paid like this.

Guess I'll just be quiet about it for now until this is over...
Click to expand...

My Super 250 has a piston and cylinder that look similar in condition to your "frankenmess" through the exhaust ports. Compression is low, and there's some rod or bearing noise when she turns over. The ring gap is HUGE on my saw...........probably at least.125" on both rings as she sits now. Gotta pull it apart and do some measurements to see what I need....
 
8433jeff said:
Nice to have a 24, but saw will be happiest with a 18, 20. For something to buck the big stuff, they work pretty good. Don't ask me to carry one any distance.
Click to expand...

How bout the only saw... I might need a little bit bigger bar to cut some maples down on one of my dad's friends property for firewood. I don't know how big the trees are, but given how long that guy has lived there, they might be fairly big.

stinkbait said:
You should run an 18" and you're be happier.
Click to expand...

Nah, too small... :) I need to grind down the "safety bumpers" down and it'll cut a bit faster. (no, not rakers, the little bumper in front of those) I have a lead on a bunch of 610's and 605's from another member on here, and will try to get my paws on them. I might port a couple of them, and make 'em work harder and cut faster. :) I heard these grenade at a certain RPM, but don't remember what it was... I'll have to look for that thread.
 
promac610 said:
How bout the only saw... I might need a little bit bigger bar to cut some maples down on one of my dad's friends property for firewood. I don't know how big the trees are, but given how long that guy has lived there, they might be fairly big.
Click to expand...

Well an 18" bar should cut down a 36" tree.
 
ric5141 said:
Nice spikes...you make those?
Click to expand...

Nope, a guy on ebay is selling off what I believe to be the last of the original McCulloch bucking spike accessory kits, grab one if you need it, that guy is the only guy that I know of that is selling the kits with the original box, and bolts/nuts and BOTH spikes. You get the inner and outer spike, not just one. Link: McCULLOCH 610 ORIGINAL SPIKES FOR CHAINSAWS 214208 NEW - eBay (item 380295038578 end time Jan-30-11 19:50:35 PST) He apparentely raised the price about four bucks... but if you want/need them, I would get them. You may have to grind the top of the inner spike where the lump above the screw hole interferes with the fit. I used a sharpie to "paint" the spot I ground down, as it was in a protected area. If you need a pic, let me know.
 
promac610 said:
Yeah, but I don't wanna walk around the tree with this heavy bastard if I can help it! :laugh:
Click to expand...

I also like having a bar that is longer than the cut so if you want to stay with the mid-size MACs, save up your coins and get a 82cc for the job - SP80, SP81, SP81E, PM850, PM800, PM805, PM8200 or DE80. You get anti-vibe and the muscle to pull a much longer bar. If you want to stick with the 600s, rumor is the 650 is the strongest one. Just my two cents. Ron
 
rwoods said:
I also like having a bar that is longer than the cut so if you want to stay with the mid-size MACs, save up your coins and get a 82cc for the job - SP80, SP81, SP81E, PM850, PM800, PM805, PM8200 or DE80. You get anti-vibe and the muscle to pull a much longer bar. If you want to stick with the 600s, rumor is the 650 is the strongest one. Just my two cents. Ron
Click to expand...

Wish I had moolah for some of those saws, don't have it, and won't for a couple years yet.

hwrdpromac800 said:
I saw my cousins 3.4 eager beaver run my 28 inch bar and full skip chain. It wasn't a speed demon but got the job done. We were both amazed.
Click to expand...

That's what I was planning on doing. Did you use it on hardwood, or softwood? What bar and chain was it?
 
Yes, that six-ten would wear skip chain at 24" or longer for me. Besides keeping the chain moving, the r's up and the clutch cooler, it will also save some weight. A new 28" bar for that saw would go a long ways towards one of the above saws, and then you would have another Mac. Winner, winner, chicken dinner.
 

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