79CC HF motor and crank size

GoldenMotor.com

gokart25

Member
Sep 26, 2011
245
1
16
Iowa
I was in Harbor Freight today and they had a 79cc 4 stroke motor on display.
I like the size of it, but the output on the crank is not the normal 5/8'', it's smaller.
What are people doing here with the small output shaft?
Do you have to run a transmission, or can you just get a gokart clutch to fit?
Any picture of what people have done would be great.
Thanks
 

azbill

Active Member
May 18, 2008
3,358
5
38
63
Fountain Hills, Arizona
hmmm, this is cut n pasted from this page
http://www.harborfreight.com/79-cc-ohv-horizontal-shaft-gas-engine-69733.html

Displacement: 79 cc
Engine cycle: 4 stroke
Compression ratio: 8.5:1
Shaft size: 5/8" (16mm) diameter x 2.4" (60.1mm) L, end tapped 5/16-24 with 3/16" keyway
Fuel capacity: 0.53 gallon (2 liter)
Height: 11-3/4"
Width: 12-1/4" (from end of crank to starter recoil)
Width: 11-1/2" (from air filter to fuel tank)
Mounting base pattern: 102mm L x 104mm W - 61.5mm W (4" L x 4.9" W - 2.4" W )
Shipping Weight: 26.65 lb.
 

gokart25

Member
Sep 26, 2011
245
1
16
Iowa
Ok, I'm a little mixed up here..
I was thinking about go kart clutches that fit 3/4" shaft, and when I saw that the shaft on the 79cc motor was smaller than I was used to seeing, I wondered how and what fits the 5/8" shaft.
I take that the pulley on the EZM fits 5/8'' and would bolt right onto the 79cc?

What are people doing here with the small output shaft?
Do you have to run a transmission, or can you just get a gokart clutch to fit?
Any picture of what people have done would be great
.


I would really like to try a 4 stroke motor, if I could get it to fit..
Thanks
 

BigBlue

Member
Nov 29, 2011
781
0
16
California
My suggestion, if you need to use a 3/4" to 5/8" adapter on a 79cc engine, you are probably using the wrong clutch. EZM or a AGK 5/8" clutch are 2 options that you have with the 5/8" shaft.

Good Luck,

Chris
AKA: BigBlue
 

MaxPower

New Member
Jul 1, 2009
551
1
0
Sierra Vista AZ
Be careful, 5/8" is not 16mm. My 99cc pred had a 16mm shaft and I had to ream out the clutch to fit. I've read some people using sand paper on the shaft to make it smaller too. Just be aware of this and save yourself the confusion.
 

atombikes

New Member
Feb 14, 2010
525
2
0
Northern VA
Be careful, 5/8" is not 16mm. My 99cc pred had a 16mm shaft and I had to ream out the clutch to fit. I've read some people using sand paper on the shaft to make it smaller too. Just be aware of this and save yourself the confusion.
I thought the 16mm thing was a manufacturing "glitch" that only occurred with the 99cc model, later to be "fixed" before they stopped building the 99cc? I have the older Greyhound model 79cc and the 5/8" MaxTorque clutch is a perfect fit.