Now let’s start talking
about building a go-kart. First you need to get your hands on a
good/powerful engine. A go-kart should be built around the engine. You
can get a go-kart engine from several different machines. This will
depend on the local availability. For example, for people that live in
colder parts of US, you can get cheap snowmobile engines that can be
converted into a go-kart engine. And for others, you can probably get
your hands on salvaged bikes or lawn mower engines. You should go for
engines over 8HP. Here is a list of some possible engine donors and
there benefits and drawbacks.
First lets divide engines on water and
air cooled engines…
Air cooled: Nearly all smaller
engines are air cooled. Cooling is provided by the wind which cools the
cooling fins around the engine when the vehicle is moving at a fast
pace. So they are not made to run in one place. These engines can be
clearly recognized by their large cooling fins. They are the best ones
to have as you don't have to be messing around with radiators. Air
cooled engines are simple, but should not be run for a long time in one
place. (VW bug engines are most well known air cooled engines).
Water cooled: These systems use
fluid which runs through the engine for cooling. This liquid runs to a
cooling radiator. A fan may also be incorporated to cool this radiator
if the vehicle is stationary. With water cooled engines, revs can be
kept high without the risk of overheating. That's basically the only
advantage. Water cooled engines are more durable but they are more
complicated since water system needs to be setup, and if system does
not work, engine is in trouble. Simply too complicated for a project of
this type.
Engine donors:
Motor-cycle Engines:
These are the most versatile engines
for use on go-karts and off-road vehicles. With their gearbox and
clutches they require little messing around with. However these are not
easy to come by, but for the fortunate few you're in luck! Whether it
is a two-stroke or a four, small or big, it still is the best option.
You can use up to 80% of bike for your go-kart project. The easiest way
to build a go-kart is to use a motorcycle engine. Problem: They are
made to go fast, therefore have a low torque. They are not cheap over
$500, some of them are water cooled. They can take a lot of space. If
you don't want to overcomplicate thinks then this is a way to go. If I
was doing my project all over I would use motorcycle engine.
Lawnmower Engines:
Lawnmower engines are usually somewhere
within the region of 3.5 - 18hp, which is fairly powerful. However
these engines are slow, producing between 3500rpm and 4500rpm. The good
side to this is that they produce plenty of torque to get a kart in a
motion. They are also very cheap and readily available. Problems: They
have vertical shaft, and the wheels are horizontal. They require a lot
of adoption and messing around. "If only we could just put the engine
on it's side". If only!. However this is not the best of ideas as you
risk top end failure - piston seizure etc. The problem is the fact that
the drive axle (power shaft/ crankshaft comes out from the underneath
of the engine. Producing vertical drive, however our rear axle turns in
a horizontal axis. And it is this problem of getting the power from the
engine to the rear wheels. So, if you are planning to use this type
engine make sure you get your hands on some type of adapter. If you are
getting engine from a lawnmower riding tractor then make sure you get a
differential.
Other small vertical shaft engines:
Many of these engines come from leaf
blowers and similar machines. They are great engines, and since they
have vertical shaft they make things less complicated. More powerful
ones can be bought in small engines stores, but they are not cheap.
They are perfect engines for building a go-kart, the only problem is
that they are not cheap and you need to get your self a clutch as well.
Snowmobile engines:
In some parts of the US these can be
cheap, and they have a lot of torque. Problem:
they are made to run in
colder weather, so heat is a big issue during the summer.
Car engine:
There are few versions of go-kart that
use Mini Mores engines (only in UK), Fiat 126, VW and etc. They are
great engines, have plenty power and torque. Problem: not cheap and
very heavy, probably too heavy for this type of car. Need original
transmission, clutch and etc. It is hard to find a small car engine
that will fit a go-kart type car, most of these are too large, too
powerful, or hard to find.
Jet Engine
Yap, jet engine. You could build one
your self as well. :-) "Go with a
style"
DiY
project website
Other possible donors:
* Chain-saw Engines
* Generator Engine
* Moped Engines
* Generator and Water Pump Engines
* Reclaimed Go-Kart Engines
* Rotavator Engines
Horsepower of engine:
In this case size does
meter :-) For most of the go-karts 5-8 HP
engines is a minimum. 8HP engines can push a go-kart up to 40Mpg, of
course everything depends on you gear ratio. To find the top speed for
your engine use this calculater [link]. If
you get engine over 10HP you
can create a larger gear ratio. This way your go-kart will have more
torque and clime hils with no problems.