Kids (and adults!) looking for thrills will find that riding a minibike can satisfy their need for speed while simultaneously developing motor skills and instilling responsibility.
Begin by following the instructions that come with your plans to assemble a sturdy frame that can support all components, including the engine.
Frame
A strong minibike starts with its frame. Weld it jig-welded from high quality 7/8"x.083 wall tubing purchased from any home improvement store or online. This project can easily be undertaken by children as its construction is designed to be easy and forgiving for beginner welders/tube benders alike.
Start by cutting the old bike frame down to its new configuration as shown in fig 2. You may need to bend forward the "gooseneck" section with heat from a propane torch or large jack, taking care not to compromise its strength while making sure that its bends are smooth and round.
Once your frame has been cut and bent, it's ready for jig welding. Construct a simple wooden welding jig and insert the lower portion of the tube in it - this will serve as the mounting for both the engine and seat post.
Homebuilders looking for an engine suitable for minibike racing should look no further than a Honda GX200 engine, which starts out rated at about 6.5HP in stock form but can easily be made to double that power through standard tuning modifications (larger valve cylinder head, bigger compression piston, larger carburettor). It offers plenty of horsepower with its belt drive transmission - perfect for fast, slick racing on flat ground as well as rugged hill climbing.
Wheels
Mini bikes need sturdy wheels to function effectively and offer your children an introduction to mechanical engineering and tinkering. Watch their imaginations unfold as they dream up all sorts of fun accessories to add to the ride!
Aluminum and steel wheels are two basic choices when selecting wheels for your minibike. Aluminum wheels tend to be lighter, cheaper, and stronger compared to their counterparts - perfect if racing your minibike is part of your plans! However, steel wheels will stand up better against competition's rigorous conditions.
Cast aluminum wheels are an economical and resilient choice for most applications, ideal for everyday driving conditions. Furthermore, their aesthetic qualities outshone those of more expensive forged wheels typically used only in high performance applications.
Minibike owners have access to an abundance of wheels and tires designed specifically for minibikes. When selecting any wheel type, make sure that it works with both your engine and suspension systems, otherwise it could leave you with an ineffective hunk of junk that cannot withstand its power output.
If you're in search of an inexpensive minibike that can tackle hill climbing and aggressive riding, upgrade your old pull-start machine by upgrading its wheels, engine swap, and other goodies to give it an edge over its competition. You might be amazed at just how far your little machine can travel once upgraded with appropriate upgrades; just don't forget your helmet for safety sake - never know when you might need one!
Suspension
Suspension systems serve to mitigate bumpiness from wheel to vehicle contact points. Furthermore, they maintain optimal tire contact with the road surface by increasing friction and tire grip as well as dissipating energy from acceleration thereby decreasing body roll during cornering. Composed of springs and shock absorbers attached to its frame, suspension systems help ensure a comfortable journey.
Suspension can have multiple meanings. One definition entails stopping something officially and often temporarily; this could mean, for instance, suspending air travel for safety reasons or hiring decisions temporarily being put on hold by companies. Suspension may also refer to uncompleted actions such as court cases left suspended over an extended period or the release date of new movies being extended by three years.
Suspensions are heterogeneous mixtures of solid particles suspended throughout a liquid that do not dissolve. Large enough to be seen with the naked eye, suspended particles can be differentiated from liquid by scattering light passing through them - known as the Tyndall effect. They distinguish themselves from colloids which consist of particles with sizes between 2-1000 nanometers that must be observed via microscope.
When you're ready to take your minibike racing seriously, add an upgraded engine and drive train with an improved torque convertor for hill climbing capability. In turn, this transforms it into an affordable racer perfect for anyone wanting to get out on the track and compete!
Electronics
Most stock mini bikes use either 24V or 36V lead acid batteries for power. As these cheap yet heavy batteries require careful mounting, be mindful when installing them. Once mounted and wired up with batteries and motor controller, wire them all together using motor controller's two leads for battery connection and then 2 or 3 motor leads (2 for brushed motor, 3 for brushless). You can then use Matlab script to get an acceleration profile profile.