MCCULLOCH The official McCulloch thread

[Mac131]

I am posting these publications guides up for McCulloch saws which can help narrow some production dates. Handy to have for reference.

The best one I've found is the 1979 version. I have a 1972 version and a 1998 version. The 1998 version has some errors.

The 1979 version would put a 12- 2-10A 6/67 to 6/68.

If anyone has other guides, it would be good to get copies of those.

Very cool! Thanks for sharing these!

 

[Mac131]

Got a full wrap handle installed on my freshly ported 10-10. Thanks Mark! Soon I'm going to test it out against my stock Mac 10-10 and stock Pro 10-10 to see how it does! Got some sweet dogs coming for it as well!

 

[heimannm]

Jeff - Once again Tim read slowly and actually answered your question. I was still in PM6 mode when I provided those dates. I am sure his information is more accurate.

Mark

 

[Mac131]

It's ok Mark! We got it figured out!

 

[Definitive Dave]

Sounds serious! Is it strictly a cookie cutter saw?

I like square cookies very much

 

[Definitive Dave]

Dave -

The Mc91 and 91b use a different fan housing/cylinder shroud than the 790/795/895. This is what the 795 fan housing looks like:



This is what the Mc91/91b cylinder shroud and fan housing look like




The clutch and flywheel can removed with a steering wheel puller, assorted long SAE bolts, and some Stihl bar nuts to keep the long bolts in place on the puller.

I think the threads on the flywheel are 1/4-20 and the threads on the clutch are 10-24. Mark Heimann can verify.

The 795 is an easier chassis to shoehorn a kart motor into because you don't have to modify the head. If you want to shoehorn a kart motor into the SP chassis,
you have to make a provision for the rear vibration mount to fasten to the head and you may have to do some shaping of the cooling fins, depending on which shroud you want to use.

The 795/797 style chassis is my favorite, I am looking at other options because I would rather have a left hand start for racing purposes.

 

[Definitive Dave]

As Jacob stated the MC91 fan housing will not fit. The 91 is not a super series motor like the 795, 797 and 125 are.
Why are you using a 125 block instead of the 101B block that has the removable head. As for tools i made my own
that works for Mac flywheels, Mac clutches and Homelite flywheels like the 2100 models.

And where did you find that crank.

Good luck on your build, Sounds impressive.

For the final build I plan to use the 101B kart motor but ...If I can get a bag full of extra CCs by going with the big bore 125 setup well.....POWAH!!!!
Crank is a one off build.

 

[Definitive Dave]

Dave - You may want to look for one of these - McCulloch used some special cap screws for the connecting rod bolts on many of the 123 cc engines.

CRANK CAP SCREW TOOL SOCKET McCULLOCH CHAINSAW 125 SP125 101 KART 85583 BOXUP649 | eBay

Some of the saws use a piston with a blind end so it takes a special puller to extract the wrist pin. I think Duke's kit could be made to work but you would have to make some kind clip to put on the blind end to pull the pin.

The bearings normally stay on the crankshaft so a bearing separator is handy to have.

14pcs Bearing Separator Puller Set 2" & 3" Splitters Bearing Remover Service Kit | eBay

As JJ noted, the threads in the flywheel are 1/4-20, it is a good idea to leave the nut on the crankshaft (backed off a few turns) with using a puller as the flywheels will occasionally become UFOs when they pop off. There are also two 1/4-20 tapped holes in the crankcase cover to facilitate opening the crankcase.

View attachment 290461

I was thinking the tapped holes in the clutch were 8-32 but I cannot confirm or deny that.

Mark

U Da Man!!!!

 

[Definitive Dave]

Cool build! 150cc! Nice, the Stroker crank Will really wake up the 125, and allow you to set up a good squish, like that! Where did you get the crank?

custom one off crank, at least so far

 

[jacob j.]

The 795/797 style chassis is my favorite, I am looking at other options because I would rather have a left hand start for racing purposes.

It's pretty easy to convert the 7** series chassis to left-hand start. The fan housing has divots on the back side that can be drilled through for mounting a starter on that side. You need the starter with the short-throw pawl cup and then if the flywheel isn't equipped with pawls and springs, you'll need to install those. I can help with some parts for that.

 

[Lee H]

The 795/797 style chassis is my favorite, I am looking at other options because I would rather have a left hand start for racing purposes.

My favorite too, Here is a Super 797 and a 797 chassis with a 101

 

[heimannm]

Mark

 

[Definitive Dave]

mine aren't currently very pretty but....



The puller set Mark recommended is on the way and I will contact Duke today to get his tool as well.
I have one of the donor 125cp motors at Joe's shop for boring experiments.
I snagged the billet rod for the stroker crank over the weekend
https://www.ebay.com/itm/Vintage-kart-McCulloch-Mc-101-billet-steel-connecting-rod-new/324568412518
baby steps
So far I know I will need a new clutch nut (mine is split) and wrap handle (redneck repairs on mine).
Is there a particular MC model that would have a left side recoil, right side clutch cover and full wrap handle that would all swap to my 795?
thanks for our help
Dave

 

[jacob j.]

I know the CP-125 and SP-105 have the left-hand starter set-up that would swap right over to your 795 (they both use the narrow shroud I think), plus they have the right clutch cover.

It's easy enough though to make your own starter set-up. You can also use the SP-125 starter set-up with the thick shroud as long as you have the long-throw cup. Mark and Nathan probably
know of some other donor models.

As far as a handle goes, @heimannm can probably set you up with a re-pop handle.

 

[heimannm]

I have a few of the steel reproduction handles still available. I will try to look in the attic to see what I have for flywheel covers and what options may exist. As JJ pointed out, the starter from any of the large frame left hand start saws can generally be fit to the FW cover of the Super series engines if they have the hole locations marked.

This is a 795 and you can see the bosses where the starter would mount. There are dimples inside the cover to indicate where the hole would go.



Mark

 

[Woodslasher]

I have a few of the steel reproduction handles still available. I will try to look in the attic to see what I have for flywheel covers and what options may exist. As JJ pointed out, the starter from any of the large frame left hand start saws can generally be fit to the FW cover of the Super series engines if they have the hole locations marked.

This is a 795 and you can see the bosses where the starter would mount. There are dimples inside the cover to indicate where the hole would go.

View attachment 291889

Mark

What's the sticker say?

 

[Maintenance Chief]

mine aren't currently very pretty but....
View attachment 291868 View attachment 291869 View attachment 291870 View attachment 291871


The puller set Mark recommended is on the way and I will contact Duke today to get his tool as well.
I have one of the donor 125cp motors at Joe's shop for boring experiments.
I snagged the billet rod for the stroker crank over the weekend
https://www.ebay.com/itm/Vintage-kart-McCulloch-Mc-101-billet-steel-connecting-rod-new/324568412518
baby steps
So far I know I will need a new clutch nut (mine is split) and wrap handle (redneck repairs on mine).
Is there a particular MC model that would have a left side recoil, right side clutch cover and full wrap handle that would all swap to my 795?
thanks for our help
Dave

I know your building a fire breathing monster with this, how come I always see the hl or hs style carbs and not something from the small or model airplane carbs?

 

[jacob j.]

I know your building a fire breathing monster with this, how come I always see the hl or hs style carbs and not something from the small or model airplane carbs?

Nathan @Bigmac I think was using some larger Walbros on some of his builds, like the Walbro carbs from the Yamaha YT-100 kart motors and such (WB-3 or WB-37?)

 

[Bigmac]

I know your building a fire breathing monster with this, how come I always see the hl or hs style carbs and not something from the small or model airplane carbs?

As Jacob has said, I have used the wb37 off the 200cc paramotors and wb3 fron the 100cc Yamaha kart motor. Both work fine.
The HL carb is a direct bolt in for a 797 style chassis, so that makes it a very popular swap, and it came stock on a few models as well. You can easily adapt an 090 carburetor, it has a 1 inch bore, and they are cheap

 

[heimannm]

This is the best I can offer.



FWIW, there was a larger HL carburetor (272A) used on some of the 170 welders that had a .875 venturi and a 1" throttle bore but they are rather hard to come by.



The other carburetor used on the welder was the same one used on the BP-1 in case you have a few of those laying around.



Mark