McCulloch Super Pro 125C motor

[IEL]

I am in the same place as you... I have a homelite 7-21 with a scored piston.. I think the cylinder will clean up, but I have to pull it first. I have been looking for a piston since I will need one anyways.
That was the end of June... Still don't have a piston, but I am in no rush. I have posted once or twice in the homelite sticky, incase anyone has one. Saws wont die if they don't run for a while... You likely won't die if the saw doesn't run in a while.


If you ask and wait, good things happen. I needed parts for my Mac s55a, and I posted in the mac thread. One member had some of the parts, and sold them to me. It was another week or two before I found someone who the other parts. I bet that if I was rushing (more) and being (more) annoying, people wouldn't have tried as much to help me.

People know what you need. I would say your best bet is to just sit back, and wait a few weeks to see if something comes up. You can find almost any part if you wait, and have people know your looking. If you run around like a chicken with your head cut off, you will have a lot less money, and regret it in the future.

Finally, if you do find someone with what you need, dont pressure them. I have found people are more likely to go out of their way to help you if you don't rush them... They don't have to do anything.. If you say it needs doing NOW, they will often do less, and sometimes tell you to screw off... If you say your in no rush, and whenever it works for them, they will be happy, you will get your stuff, and you will both have someone to talk to about parts, saws, or fixing issues...

Sorry for the long post, when I get ranting its hard to find a place to stop. Just trying to save you a lot of time, energy, and your chances of getting help...

 

[Bubba Stump]

Anybody out there know if there are any recent made oil seals that will fit the SP125 motor, I am talking about something you could find at a local automotive parts store or a tractor/machinery parts warehouse? The reason I ask is because I don't know if I trust the rubber on a set of OEM seals that have been sitting dry on a shelf since the 70's. rubber back then was not like today. Does anybody have any input on whether OEM are Good or not, or am I being paranoid. Most of the saws that I have rebuilt are Stihl or husky and there are aftermarket new seals etc. that are available and I use the Aftermarket stuff. I have never had any problems with the aftermarket products.

 

[ozflea]

Anybody out there know if there are any recent made oil seals that will fit the SP125 motor, I am talking about something you could find at a local automotive parts store or a tractor/machinery parts warehouse? The reason I ask is because I don't know if I trust the rubber on a set of OEM seals that have been sitting dry on a shelf since the 70's. rubber back then was not like today. Does anybody have any input on whether OEM are Good or not, or am I being paranoid. Most of the saws that I have rebuilt are Stihl or husky and there are aftermarket new seals etc. that are available and I use the Aftermarket stuff. I have never had any problems with the aftermarket products.

Try searching

Mcculloch Chainsaw 125 105 MC93 MC101A Crank Seal | eBay

NEW Mcculloch Super PRO 125 125C Chainsaw OIL Seals | eBay

McBob.

 

[heimannm]

Measure the bore the seal fits in, and the shaft it fits over. You will be able to find the seal at any good bearing distributer. You will not find the thin cross section seal for the flywheel side cover if yours presently has two seals but you can find a "double lip" seal that will be the same cross section as one of the thicker seals that will work. A lot of guys don't even bother with the double lip seal and simply go with one single lip seal in that location.

If you happen to remember, write down the seal description and post it. I have been through the exercise recently (twice in fact) with the kart engines for my hot saw project and had the appropriate seals on hand already. I have the notes in my shop but I am around 6,000 miles away at the moment...

The seals are standard sizes (expect for the thin one), I just don't remember what they are.

Mark

 

[Bubba Stump]

Quick question for you McCulloch fans out there. What size spline socket/wrench do I need for the Mcculloch conncting rod bolts? Mcculloch did make a special wrench for these(pt. #85583), but I can't find one. I thought that I could go down to the hardware store and buy a couple of machine bolts to replace the original spline bolts but that did not work out for me. I took an original with me and found what I thought was what I needed. the threads matched up and the bolts looked the same but apperrently the mcculloch bolts are a specialty bolt because the other bolts fit way to tight. they would screw in about 3/4 of the way in the rod and then would get to tight. I decided to tap the threaded hole to see if there was some debris but the tap would almost go all the way and then get to tight. long story short, I ended up breaking a bolt off in the rod. lucky for me I did all of this on a spare rod that was no good before I went on to the good rod. Anyway, I was wondering if a spline socket for anti theft bolts or something would fit the mcculloch rod bolts, and what size would I need (standard or metric)?

 

[OREGONLOGGER]

Quick question for you McCulloch fans out there. What size spline socket/wrench do I need for the Mcculloch conncting rod bolts? Mcculloch did make a special wrench for these(pt. #85583), but I can't find one. I thought that I could go down to the hardware store and buy a couple of machine bolts to replace the original spline bolts but that did not work out for me. I took an original with me and found what I thought was what I needed. the threads matched up and the bolts looked the same but apperrently the mcculloch bolts are a specialty bolt because the other bolts fit way to tight. they would screw in about 3/4 of the way in the rod and then would get to tight. I decided to tap the threaded hole to see if there was some debris but the tap would almost go all the way and then get to tight. long story short, I ended up breaking a bolt off in the rod. lucky for me I did all of this on a spare rod that was no good before I went on to the good rod. Anyway, I was wondering if a spline socket for anti theft bolts or something would fit the mcculloch rod bolts, and what size would I need (standard or metric)?

At the shop here I use Metric torques sockets #6 is the ticket yeh those do not go back on and go in the trash..make sure you match the rod cap dots when re-installing the rod cap only goes on one way and 24 bearings..good luck

 

[OREGONLOGGER]

Yeah, If I use a 797 piston I think I will have to have a 101 or CP125 con rod. If a 797 will work or I can find a rod I will PM you.

You'll need a 797 rod 101 won't fit..sorry

 

[Bubba Stump]

You'll need a 797 rod 101 won't fit..sorry

I have been corrosponding with a Custome vintage Kart builder back east. I sent him measurements of my crank, piston pin, con rod and everything that I will use with my build. I also took a buch of rough measurements with a digital caliper and made a mechanical draft of what the Ideal Conrod would need to measure to fit. after a few days he responded and siad that He had a mc-101 rod that would work for my application. I bought it and received it just the other day. I measured it against my SP125C rod and it looks like it will be fine. the length looks good and the piston pin and width in the piston gap fits nicely. the only thing that might be an issue is the thickness of the bottom of the rod. the original SP125C rod is about 0.473" wide and the 101 rod i got is 0.439"wide. everything other than that is right on the money. the Kart guy said this should not be an issue but I don't know. Is the width the gap on either side of the con rod when it sets on the crank going to be that critical?

 

[ozflea]

I have been corrosponding with a Custome vintage Kart builder back east. I sent him measurements of my crank, piston pin, con rod and everything that I will use with my build. I also took a buch of rough measurements with a digital caliper and made a mechanical draft of what the Ideal Conrod would need to measure to fit. after a few days he responded and siad that He had a mc-101 rod that would work for my application. I bought it and received it just the other day. I measured it against my SP125C rod and it looks like it will be fine. the length looks good and the piston pin and width in the piston gap fits nicely. the only thing that might be an issue is the thickness of the bottom of the rod. the original SP125C rod is about 0.473" wide and the 101 rod i got is 0.439"wide. everything other than that is right on the money. the Kart guy said this should not be an issue but I don't know. Is the width the gap on either side of the con rod when it sets on the crank going to be that critical?

Straight swap ol mate just check the clearance on the stuffer

 

[Bubba Stump]

Straight swap ol mate just check the clearance on the stuffer

I checked the play of both rods on the crank just a little bit ago and they both feel about the same. I used new crank to rod needle bearings and they both seem to show the same play. The rods have some movement side to side but seem good and tight up and down. is this the clearance you are speaking of or something else I need to check? Also, when installing the new piston onto the rod should the pin be pressed on only or should the rod be heated at the pin spot and the pin frozen to install it like you would on some type of dirtbike rods?

 

[Bubba Stump]

Straight swap ol mate just check the clearance on the stuffer

Sorry ozflea, mind had a brain fart. you are talking about clearance of the stuffer plate that goes between the bottom of the block and the oil tank. If There are clearance issues in this region, do you have to somehow shim the stuffer or would I have to grind the contact area on the rod? I think I might have seen some metal spacers that resembled a gasket for some Kart applications.

 

[Bubba Stump]

Anybody know if stainless steel machine bolts will work OK for Connecting rod bolts? I went to Lowe's hardware, Home Depote, Tractor Supply, Autozone, Oreily's, Nappa and Car Quest and could not find a machine screw in a #6-32. You know, the black Allen head style. The only thing that small in a narrow machine cap screw like what I need is the Stainless Steel version. Would the stainless steel be to weak or does having a strong bolt not make any difference. If I could find a socket that would fit the original McCulloch bolts, I would just leave them but nothing comes close to fitting.

 

[Busmech]

Bubba, contact Vintage Vixon thru vintage kart parts on ebay, she has both the L wrench and the 1/4 drive socket that fits the mac bolts. you will have to grind the stuffer and block to make room for the allen head cap screws

 

[ozflea]

Anybody know if stainless steel machine bolts will work OK for Connecting rod bolts? I went to Lowe's hardware, Home Depote, Tractor Supply, Autozone, Oreily's, Nappa and Car Quest and could not find a machine screw in a #6-32. You know, the black Allen head style. The only thing that small in a narrow machine cap screw like what I need is the Stainless Steel version. Would the stainless steel be to weak or does having a strong bolt not make any difference. If I could find a socket that would fit the original McCulloch bolts, I would just leave them but nothing comes close to fitting.

Use only the correct bolts I have just managed to find 12 sets on ebay and now there here .... the rod bolts are the week link in Macs bottom end

And try vintage vixen from nevarda

 

[Bubba Stump]

Bubba, contact Vintage Vixon thru vintage kart parts on ebay, she has both the L wrench and the 1/4 drive socket that fits the mac bolts. you will have to grind the stuffer and block to make room for the allen head cap screws

Busmech, thanks for the info. I have contacted your source and am waiting a response. I really was not to keen on replaceing the originals with the allen machine screws just for the fact that most all of the ones in the stores that I listed were all made in china or elsewhere, not to mention the manufacturers brobably did not intend to have them used for my application. I was reading elsewhere that the bolts should definately be replaced with new factory replacements if the motor was ran hard. This may not be true for chainsaw aplications though because the information was on a Kart racing site. the site said that most all the time there will be unseen fractures in the bolts and if reused you would risk throwing a rod and destroying your efforts. This is my first McCulloch build and I don't want to take any chances, especially with a engine block that has a $300+ resleeve job.

 

[Bubba Stump]

Use only the correct bolts I have just managed to find 12 sets on ebay and now there here .... the rod bolts are the week link in Macs bottom end

And try vintage vixen from nevarda

Maybe I am looking under the wrong search words, but I could not find any replacements earlier. What are they listed under? Also, are you saying the Factory ones are junk? I am becoming confused about this. A Kart racing site says to replace with original equipment and other people are saying aftermarket. what bolts should I be looking for for reliability and strength?

 

[ozflea]

Busmech, thanks for the info. I have contacted your source and am waiting a response. I really was not to keen on replaceing the originals with the allen machine screws just for the fact that most all of the ones in the stores that I listed were all made in china or elsewhere, not to mention the manufacturers brobably did not intend to have them used for my application. I was reading elsewhere that the bolts should definately be replaced with new factory replacements if the motor was ran hard. This may not be true for chainsaw aplications though because the information was on a Kart racing site. the site said that most all the time there will be unseen fractures in the bolts and if reused you would risk throwing a rod and destroying your efforts. This is my first McCulloch build and I don't want to take any chances, especially with a engine block that has a $300+ resleeve job.

Bubba stick with the original stuff or kiss ya ass good buy

 

[Bubba Stump]

Bubba stick with the original stuff or kiss ya ass good buy

Ozflea, I have seen your website and am quite impressed. I am not going to go against your endless supply of Mac knowledge so I will stay with the original splined bolts and have to deal with finding the right tool. I had another question for you while I am here. Can a MC-101AA fit a SP125 saw or be modded to fit? I quess what I want to Know is, will the MC-101AA work for a saw?

 

[ozflea]

Ozflea, I have seen your website and am quite impressed. I am not going to go against your endless supply of Mac knowledge so I will stay with the original splined bolts and have to deal with finding the right tool. I had another question for you while I am here. Can a MC-101AA fit a SP125 saw or be modded to fit? I quess what I want to Know is, will the MC-101AA work for a saw?

Certainly can and will

Heres mine





McBob

 

[Bubba Stump]

Certainly can and will

Heres mine





McBob

Very nice, I am envyous. I was asking because a totally rebuilt one came up on ebay for $750 but I did not know if it would work. It is to late now though, someone scarfed it up while I was asking you about it. Anyway, very nice. It's like an old vintage muscle car that has been sitting in a garage for years. The body is rough and unsightly and you think its a peice of junk until you lift the hood and find a huge, beautiful big block with all the goodies.