Big Engine Bicycle 79cc 4-stroke

ducatiluke
man thats one **** of a bike. 55mph is pretty crazy. sounds fun.

ZnsaneRyder
yea where did you get yours at. or did you make them. did you buy the complete jackshaft kits for gokarts. also what did you do to the carb to run it with a throttle cable.
 
Howdy folks, I just got one of those Harbor Freight 79cc motors for 79 bucks. The guy at HF offered me a two year extended warranty. I asked him what it covered and he said any thing but theft. He said if the engine failed for any reason, as long as I could still carry back, he would replace it with a new one for two years. That seem like a heck of a deal. I wonder if this engine would pull you off the start with a 5:1 ratio to a 22" diameter wheel. The ratio calculator says it would roll at 47mph @ 3600rpm. Does any one have a guess if would take off from a stop without a lot of pedaling. :-/
 
No,and you're not likely to get to 47 mph either, except going downhill.You need a 10:1 or even higher ratio,since you will run out of torque before.
 
Don't bother with the warranty plan because your most likely going to de governor it anyways. once you de gov it then it will run at about 4200rpm Maybe 40mph max.Im actually going to see if i can get my money back for the extended warranty because its still under distributors warranty. But once i took the gov off i realized its not worth trying to get it back to stock to return it if something happened. Better to put the $20 to another engine for and keep it for parts if needed.
 
Been doing some digging around. It appears that the HF 2.5hp 79cc motor has essentially an identical shaft measurements and hole pattern as the Honda GX100-QA2 3HP motor. It's probably better to think of the 2.5 HF greyhound motor as a smaller version of the GX100 instead of a larger version of the GXH50...

And, of course, Staton makes a GX100 adapter so you can use a 78mm clutch & then use other gearbox/CVT/Transmission that uses the standard 78mm clutch mounts.
 
The problem with the staton 78mm clutch is that it is sprung for a 2 stroke. A centrifical clutch set up for a 2 stroke usually dosn't work very well on a 4 stroke. Unless they have a spring kit for the powerband rpm range simular to a 4 stroke being used.
 
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