Mcculloch CP125 reborn

[leeha]

I have had this saw for a few years and actually forgot about it.
I found it the other day and since the last SP125 resto went so
well i thought i would tackle this one and give it the same treatment.
Here are the before pic's.

Lee

 

[leeha]

I got this thing all striped down and found that there
are several differences between the CP and SP125's,
Not only doe's the CP have a different Decomp assembly
which is similar to the 797 with a different lever, The lower
anti vibe mount is different, The CP has one big reeed valve
instead of the two pedal set up. The stop switch is also very
different with a two wire system because the tank is mounted
on rubber mounts. SP saws had a ground at the front AV mount.
and a single wire switch. Mufflers are also different. The CP
shares the same muffler as a 797. Fan housings are also the thin
type as on a 797, The SP had the wide housings. Air filter covers
are different with the CP having a rear opening for more air intake.
This block looks to me like it was replaced at some time. The piston
still shows it's original part number 69301 which is standard bore
thick ring. and the block has no paint anywhere.
When i first got this saw i remember trying to get it running but it
had a bad air leak. Now i know why. Look at the pic of the intake boot.
One big hole in that baby.
Got alot cleaned up and ready for the blast cabinet.

Lee

 

[buzz sawyer]

Definitely a sign of CAD - Have a CP125 and forget about it.

Shame about the intake boot but I've heard a Stihl 088 will work. Then again, I'm sure you have an extra one laying around.

Looking forward to this one!

 

[Brian13]

Will be watching this one closely for pointers. The CP came in between the 797 and the SP125? Wonder if the porting is the same as the SP, or a little different.

 

[Jacob J.]

Yeah the differences between the CP and the SP point to the evolution of that class of McCulloch saw between the 795 and the SP-125c (795-797-CP-SP.) The vented air filter covers were sought after by cutters here for all the 125s even after the CP was discontinued and the SP introduced. All the CP blocks have the steel sleeve as well like the 797 and the ribbed exhaust. Some of the CP blocks could be set-up for either DSP or a straight compression release.

The best way to tell a CP saw from an SP saw is the round muffler. Mac didn't make the round muffler to fit the oval SP exhaust outlet. So if you see a saw that looks like an SP, but has the round muffler, then it has a CP or 797 block.

 

[Jacob J.]

Will be watching this one closely for pointers. The CP came in between the 797 and the SP125? Wonder if the porting is the same as the SP, or a little different.

The port timing is a little closer to the 797. The main difference is the exhaust port. The SP blocks have the large oval exhaust port, CPs have the bridged exhaust with the rectangular lip like the 797 block.

 

[Brian13]

The port timing is a little closer to the 797. The main difference is the exhaust port. The SP blocks have the large oval exhaust port, CPs have the bridged exhaust with the rectangular lip like the 797 block.

That makes sense. Havnt seen the SP block up close yet, to see the oval exhaust port to compare. Guess I will need to add a CP to the list as well.

 

[ChainsawmanXX]

Wish I had so many 125's I forgot I had some

Great project Lee! Always done a great job!

 

[heimannm]

CP125 is definitely on my wish list as well. Just something about the old school muscle that makes it so desireable...

Keep up the good work Lee and keep us informed of the progress.

Mark

 

[RandyMac]

The CP is a prize alright, better running than the SP, but bulkier than the 797.
I remember the first SP125C I had, I bought it in a hurry, needed a big saw and was too far from my saw depot.
I charged into the saw shop at Portola and asked the guy for a 125 with a 7 pin sprocket, 404 on a 60" bar. He stared at me like I was a Martian or a mental defective. He didn't have one, but made a few calls and had one in a couple hours. I ran 5 or 6 tanks through it, thought there was something wrong with it, it seemed, well, down on power. I took it to my regular guy, who just laughed said it was just fine, but not to expect the same level of power as the 797s I was used to. Anyway, the CP125 comes real close and won't foam the blood in your fingers.

 

[Ambull]

That's awesome Lee!!! Having a CP125 under the bench and forgetting about it. Looks like you have the resto well under control.

 

[blsnelling]

Lee, you might have to give your wife stories like this, but do you really expect us to believe you forgot you had a CP125? Well, with as many great saws as you have coming in, I guess it might be possible, lol.

 

[Mr. Bow Saw]

Lee forgot about it .:eek2: Well I know it will turn out real nice.

I got my first 125 four years ago and it is a CP.

 

[leeha]

Definitely a sign of CAD - Have a CP125 and forget about it.

Shame about the intake boot but I've heard a Stihl 088 will work. Then again, I'm sure you have an extra one laying around.

Looking forward to this one!

I do have a spare Boot Buzz. I had a feeling it was toast.

Yeah the differences between the CP and the SP point to the evolution of that class of McCulloch saw between the 795 and the SP-125c (795-797-CP-SP.) The vented air filter covers were sought after by cutters here for all the 125s even after the CP was discontinued and the SP introduced. All the CP blocks have the steel sleeve as well like the 797 and the ribbed exhaust. Some of the CP blocks could be set-up for either DSP or a straight compression release.

The best way to tell a CP saw from an SP saw is the round muffler. Mac didn't make the round muffler to fit the oval SP exhaust outlet. So if you see a saw that looks like an SP, but has the round muffler, then it has a CP or 797 block.

I knew i forgot something, The cast iron sleave
and exhast porting. Thanks Jacob.

Lee, you might have to give your wife stories like this, but do you really expect us to believe you forgot you had a CP125? Well, with as many great saws as you have coming in, I guess it might be possible, lol.

Not a story Brad, It was hidding behind a few saws on a shelf
and got lost in there. I remember trying to get it running when
i got it but since then it's just been sitting.


Thanks guys. I will be on the phone tomorrow looking
for a few parts but everything looks pretty good.
Will try to get some bead blasting done today. The
fuel tank will be a pina to paint since is two tone.




Lee

 

[leed3349]

you do good work and the saws that i got to run where awesome have fun with this project lee

 

[rwoods]

Yeah the differences between the CP and the SP point to the evolution of that class of McCulloch saw between the 795 and the SP-125c (795-797-CP-SP.) The vented air filter covers were sought after by cutters here for all the 125s even after the CP was discontinued and the SP introduced. All the CP blocks have the steel sleeve as well like the 797 and the ribbed exhaust. Some of the CP blocks could be set-up for either DSP or a straight compression release.

The best way to tell a CP saw from an SP saw is the round muffler. Mac didn't make the round muffler to fit the oval SP exhaust outlet. So if you see a saw that looks like an SP, but has the round muffler, then it has a CP or 797 block.

Best way is to pull the muffler and look at the port as 3 of my 4 125Cs had the muffler replaced with a round one. Ron

 

[Jacob J.]

Best way is to pull the muffler and look at the port as 3 of my 4 125Cs had the muffler replaced with a round one. Ron

Do your round mufflers have the true SP exhaust mount or did someone just bolt them on? You can bolt the round muffler up but it doesn't exactly match the oval exhaust port.

 

[rwoods]

Do your round mufflers have the true SP exhaust mount or did someone just bolt them on? You can bolt the round muffler up but it doesn't exactly match the oval exhaust port.

No, simply mis-replacements. I've never seen a round muffler that match the oval port. Ron

 

[Jacob J.]

No, simply mis-replacements. I've never seen a round muffler that match the oval port. Ron

Yeah that's been my experience too. Several of the SP saws I've gotten had the round mufflers bolted up to them and there was exhaust leaking all around the mount. I looked and looked for years and never found in any literature where there was a round muffler manufactured for the SP block.

 

[turtle561]

sorry to hijack- but i a see a little muffler sidebar going and i have a 797 clutch problem. a pawl rivet was loose so i popped the spring to get at the back of the rivet and tightened it. that done, i found the whole hub was brazed together.
with the shoes in place, the groove for the spring is covered. i tried the spring in the groove ,uhooked, but but couldn''t even come close to streatching it enough.
is there a special mac tool to do this ?
echo has a tapered cone and sleeve they use,see pic. the taper is slight, no more than the thickness of the spring for this to work.
someone suggested putting the spring in the shoes, as shown, then streatching them over the side plate one by one ? imho- no way, that's why i'm here.

new hub and spring in shoes

shoes shimmed open to expose groove. unhooked there was over an inch gap between ends, i couldn't do it.

the echo tool-with removeable side plate

maybe there's a tool with fingers that fit in the scallops around the side plate, put hooked spring over them, then open the top to where the spring slides down into the groove ? like opening a tee-pee frame, eh?
just wondering if there is anything in your service manuals on this. i have been lucky unhooking things up 'til now.:msp_wink: