What Engine and sprockets

[r_chez_08]

Hi
i am new to karting and wondered what size sprockets i would need to get my partually built kart going about 25mph.
it has 10" wheels, and i was thinking about getting a honda gx160 5.5hp engine. the kart is going to be used on farm tracks.
also, would the engine be good enough.(i am not likely to mod it)

 

[Kenny_McCormic]

Buy a 6.5hp "clone motor" much cheaper than the real thing and ALMOST as good. use the speed calc here http://www.diygokarts.com/speed-calculator.html

 

[r_chez_08]

ALMOST, but not as good. ive tried the speed calculator, but it doesnt include friction.
also, i have been offered a honda gx160 second hand done 3 seasons for £20.
i am also confused when people say that they have a 5hp engine that does 40mph, but that doesnt seem easily possible

 

[Russ2251]

friction

 

[Kenny_McCormic]

ALMOST, but not as good. ive tried the speed calculator, but it doesnt include friction.
also, i have been offered a honda gx160 second hand done 3 seasons for £20.
i am also confused when people say that they have a 5hp engine that does 40mph, but that doesnt seem easily possible

Friction isnt enough to bother with adding in.

55-60mph is very possible with a box stock(everything but the exhaust stock) flathead Briggs 5hp driving comet CVT transmission on a road with proper gearing.

Acceleration is reasonable(push you back in the seat as soon as the accelerator pump less engine catches on), even when said kart is taken off road(but dont expect it to climb any cliffs, going through/clibing out of a 8ft (about 2meters) deep ditch with a running start isnt hard).

If the GX160 has been taken care of thats a GREAT deal.

 

[r_chez_08]

Cheers for the quick reply. i was thinking of having 65 teeth on the axle and 12 teeth on the engine. does that sound right???

 

[Kenny_McCormic]

Tire size?(just need how tall they are, inches please) What are you running for a transmission? I had a 12-54 ratio on my old manco with the comet CVT, thats what my last post is based on. But the CVT greatly lowers the gear ratio off the line.

 

[r_chez_08]

the wheels have a 10" diameter

 

[Kenny_McCormic]

Thats 20mph, should work well with a cent clutch(gotta keep the gearing low/revs up or the cent clutch will slip a lot and burn up). 20 is quite a bit of fun off road with crude/no suspension.

 

[r_chez_08]

the engine i was thinking of getting
has a wet clutch. would that work as well.

 

[r_chez_08]

this is the engine

 

[Kenny_McCormic]

Even better, its also probably gear reduction 2:1, max PTO speed will be 1800 RPM, you will need to change gearing accordingly from your current plan.

 

[r_chez_08]

do they do sprockets small enough?

 

[Kenny_McCormic]

Yep www.mcmaster.com

 

[r_chez_08]

their expenisve! thats more than an engine!

and also what i meant to say is do they do sprockets small enough in england, but thanks anyway

 

[Kenny_McCormic]

Try a hardware store, mine consistently surprises me with what they have in stock. Are you going 1wd or live axle?

 

[r_chez_08]

what do u mean? my engine will power the whole back axle

 

[Kenny_McCormic]

1WD is one wheel driven, live axle is 2wd with both wheels driven.

 

[r_chez_08]

both back wheels are powered by the engine , and are on the same axle, so is that live axle?

 

[Kenny_McCormic]

Yep, use a 1" solid axle.