The following list of parts is based on the recommended cyclekart specifications as defined on the cyclekarts.com page here
The basic specifications for a cyclekart are as follows
- A one-seat car using Honda 17"x 1 3/4" or 2" rims, 2.50 x 17" tires
- Wheel track 38"
- Wheelbase as close to 66" as the aesthetics of the car will allow (err on the shorter side for more abstract cuteness and general attractiveness)
- Weight no more than 250lbs
- Powered by a 200cc, single cylinder, 6.5 hp Honda OHV engine (the GX200).
- Some measurements:
- Max Length: 98"
- Max Width: 40"
- 1"X3" steel framerails (84" long in the Type 59, rear axle 10" ahead of aft end) The 1" X 3" steel stock comes in thicker and thinner walls; we use the thinner 1/16".
- Front springs 24" X 1 1/4", 2 leaf 1/2 elliptics
Some very important engineering points:
Power is transmitted via a Comet TAV-30 unit to one wheel only. Braking is also on this same rear wheel by mechanical Comet disc. NO front brakes. See the FAQ for the important reasons behind this. No rear suspension (weight gain not worth it). All of the cars have the same front and rear axle dimensions. The front axle is made up from 1 5/8" O.D. tubing, and is dropped to accommodate the leaf springs, Azusa spindles and brackets are welded on. Front axle angles are taken from an old Amilcar blueprint; they're not our own, but they work well. The steering columns and steering wheel hubs are also Azusa, lengthened to suit each car. The rear axle, drive sprocket, and hubs are also Azusa: 1" X 36" long axle, 72 tooth main sprocket, #40 chain. Front springs are buggy seat springs, half-elliptic. The fixed end has been mounted at both the front and rear ends, depending on the car. It hasn't seemed to matter which end gets the shackles. The wheels are Honda Super Cub, Passport, or Trail 90. Azusa rear wheel hubs are used on their 1" axles, and the lug bolts are ground to fit inside the Honda motorcycle hubs. New through bolts are located near the hub-reinforcing webs in the motorcycle wheels. Only one hub is keyed (the right for all our cars, and the tracks are designed with this bias in mind). Be sure to grease the freewheeling hub.
The chassis is generally constructed from 75mm x 25mm RHS. You may be limited on what thickness you can get, I managed to find some 1.6mm thick from a local steel supplier but thinner would have been better as it would be much lighter. I'm pretty sure that you should be able to find a local supplier who either carries it or can order a length or two in.
The ideal chassis rail length as listed in the cyclekart specs is 2100mm but generally the steel comes in 8m lengths so it might pay to make your chassis 2000mm long so that you can get two cars (four rails) out of one length of steel.
Chassis rails generally taper in at the front end but this may also differ depending on your chosen design.
Wheels / Hubs
The ideal wheels are the trusty postie bike wheels as found on the CT90 and CT110. You want the 17" versions. It's worth pointing out that Postie bikes have a pretty strong following in Aus so you may find that they get snapped up pretty quickly. It also means that there are quite a few shops and wrecking yards that support them too.
The hubs that most builders in the US use are universal go-kart / ATV hubs like the ones sold by Akuza Here . The wheels are drilled to accept the bolt pattern of the hub and bolted in place with a plate on the outside to sandwich the wheel hub in between.
The rear axle has one driven wheel and one free wheel. The driven wheel is keyed to the axle whereas the free wheel is not and is simply allowed to rotate about the shaft (with the aid of a little grease)
The front wheels are mounted onto hubs that have bearings within them.
Steering / Front Axle
The front steering is a very basic go-kart style that uses a lever arm at the bottom of the steering column to operate tie-rods that turn the front spindles
The front spindles can either be made, or purchased and are mounted to a live axle suspended from cart seat springs. The size of the horse buggy seat springs is 24" X 1 1/4", 2 leaf 1/2 elliptics
The front axle is made from 40mm O.D. tubing, and is dropped in the centre to accommodate the leaf springs. This can be easily done if you have access to a pipe bender or your local exhaust shop should be able to make up a part for you.
So far I've not managed to find a source for horse buggy cart seat springs here in Aus, but golf cart springs look like they might be a suitable alternative.
Brakes are a go-kart single disc brake fitted to the driven rear wheel / axle only (no front brakes). These are available in both cable and hydraulic versions
Additional braking is not required as the limited power and limited braking is largely what governs the speed
The motor used is a 200cc, single cylinder, 6.5 hp Honda OHV engine (the GX200). There are various clones / copies of this engine available and it is commonly available as a small stationary / industrial engine in Farm equipment outlets. You can also buy them very cheaply online form China.
The motor is connected to the rear axle via a go-kart style torque converter and clutch arrangement by a chain drive. The drive ratio is 72 tooth main sprocket with a #40 chain
The torque converter arrangement commonly used is a Comet TAV-30 unit. There are various clone versions available online. You need to make sure that the unit you choose matches the output shaft size of your engine (generally 19mm or 3/4")
The bodywork can be made from whatever you want, in whatever fashion you feel like or are capable of making. From basic square box plywood designs to more fancy and flowing renditions of your favourite 1920's cyclecar. The choice is yours.
Generally the base of the seat extends below the chassis rails so that you sit lower in the car, this also helps to keep the centre of gravity low, which makes the car more stable. Take a look through the 'Inspiration' photo album to get some ideas. A Google search for 'cyclekarts' will also get a bunch of results too.
Happy Cyclekarting !