Building a SP125C / 101B Kart Saw

[wyk]

What constitutes a Kart Motor???? Is there a CC/displacement level,,, like 100CC's???? or is it two piece block/head config or what??

would an I-41 mac be called considered a kart motor???? what size are they????

Kart racing - Wikipedia, the free encyclopedia

The first kart manufacturer was an American company, Go Kart Manufacturing Co. (1958). McCulloch was the first company, in 1959, to produce engines for karts. Its first engine, the McCulloch MC-10,[5] was an adapted chainsaw 2-stroke engine.[6] Later, in the 1960s, motorcycle engines were also adapted for kart use, before dedicated manufacturers, especially in Italy (IAME), started to build engines for the sport.

 

[heimannm]

Kart engines were built specifically for go-kart racing. In many cases the block was the same casting at the chain saw engine, but porting was different and the kart engines are generally much higher output than the equivalent saw engine. There were other variations in the machining as some features required for a saw were not machined for the kart and vise versa.

The McCulloch kart engines ranged from around 80 cc's up to 123 cc's.

The 1-41 with removable head was very similar to the MAC10 engine, but with less aggressive porting to provide a long service life. The D-44, Super 44, and Super 44A were closer to the kart engines, later saws were de-tuned somewhat to increase longevity.

Mark

 

[Brian13]

What constitutes a Kart Motor???? Is there a CC/displacement level,,, like 100CC's???? or is it two piece block/head config or what??

would an I-41 mac be called considered a kart motor???? what size are they????

Many of the kart and saw engines were loosely based off of each other. There were karts that had one piece heads, and saw engines with 2 piece heads. It was porting that set apart kart from saw engines. The kart engines generally were geared to higher revs if I understand it right.

You beat me to it Mark.

 

[RiverRat2]

Kart engines were built specifically for go-kart racing. In many cases the block was the same casting at the chain saw engine, but porting was different and the kart engines are generally much higher output than the equivalent saw engine. There were other variations in the machining as some features required for a saw were not machined for the kart and vise versa.

The McCulloch kart engines ranged from around 80 cc's up to 123 cc's.

The 1-41 with removable head was very similar to the MAC10 engine, but with less aggressive porting to provide a long service life. The D-44, Super 44, and Super 44A were closer to the kart engines, later saws were de-tuned somewhat to increase longevity.

Mark

So how many CC's is the I-41 around 80??? and would it be considered a kart engine if it has a two piece Head/Block???

I helped my brother when he raced karts back in the late 70's earlyt 80's but they were all one piece head/block 100CC piston ported yamaha engines and yes it seems there were some Italian motors,,, Arghhhh that time in my life was kind of hard on the memory banks and a bit vague,,, errrr,,,, cloudy/smokey/hazy,,, if you know what I mean?????

Sorry about all the questions,,, I think I may have been bitten by a yellow/black Bug....

 

[heimannm]

As noted, the 1-40 and 1-41 with removable heads were developed from the same castings as the kart engines, but the porting and compression were designed to provide lower output and a longer service life.

The 1-40 saws were all 80 cc/4.9 In³.

Not all removeable head engines were necessarily kart engines, they just came from the same parents.

Mark

 

[Brian13]

The 1-41 is a 80cc saw engine. The 2-piece head has no bearing on whether or not its a kart engine. Its the porting that separates the two. The saw engines I believe would be more geared toward torque, and a kart more toward higher revs.

 

[cpr]

And on the early ones (MC-10), the heads were different, too.

 

[Ambull]

Here is a pretty good reference for Kart engines:

McCulloch Engine Identification

And McBob's website has a fairly comprehensive listing of McCulloch motors.

http://macbobaust.com/bores.html

 

[nmurph]

Nope, a kart engine is any old chainsaw sold on Ebay.

 

[RiverRat2]

Nope, a kart engine is any old chainsaw sold on Ebay.

Yeah,,, I'm beginning to see that!!!!! especdially if it is a yellow or yellow and black one!!!!!

 

[Dennis Cahoon]

Hey Lee, will this old Mac 101AA be good enough for that magic paint of yours??????......Don't tell Smelling what you payed for it.......Hahahahahahahaha!

 

[blsnelling]

I bought another block tonight. Anyone have a line on a piston a little more than .070" over? It has a clean bore, but no piston.

 

[Dennis Cahoon]

I bought another block tonight. Anyone have a line on a piston a little more than .070" over? It has a clean bore, but no piston.

Lee won't need a piston with this one Brad.......just move compression release, add parts and paint!.......Yeeeeeehaaaaaa!

 

[Ambull]

[video=youtube;e7z_ztMxBgk]http://www.youtube.com/watch?v=e7z_ztMxBgk[/video]

 

[Brian13]

Hey Lee, will this old Mac 101AA be good enough for that magic paint of yours??????......Don't tell Smelling what you payed for it.......Hahahahahahahaha!

Nice looking motor!! Sounds like its going into good hands.

Been wanting a 101 for awhile to play with, just havnt had the funds. You guys are making me jealous with all these 101 builds:msp_tongue:.

 

[little possum]

Im not jealous Brian. I am hoping 125, 797, 895 prices will come down

 

[Brian13]

Im not jealous Brian. I am hoping 125, 797, 895 prices will come down

LOL, I am jealous and hoping the prices will come down.

 

[Dennis Cahoon]

Sorry boy's......the 125's and 101's I have left are getting like gold.......and going up as we speak!......but at least they have good pistons........Hahahahahahaha!

 

[Dennis Cahoon]

Looks like this 125c's headed to Texas!

 

[Jacob J.]

I decided to scan a great article from the old Karting World magazine on porting of the Mac kart blocks. This is kind of a long-winded article but has some great, great info on porting these blocks. I highly recommend anyone who intends on modifying one of these to read this.

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