ENGINE


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.


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