Building a Three Wheel Motorcycle: The Frame

What You'll Need
Frame jig
Steel cutter
Arc welder
Strong steel tubing - DOM is recommended
Yoke brace
Corner brace
Steering neck tube
Measuring tape

Building a three wheel motorcycle frame can be a daunting task. Here are a few steps that can help you through the process and make it go smoothly.

Step 1 - Begin with the Frame Jig and Cut

You will want to build the frame jig to the size that you are looking for. Once you have a model you can use the steel cutter to cut out the proper lengths of steel pipes for the bottom rails. You will also need to cut out the steering yoke and center brace according to the frame jig size. Use the model to cut the rear axle frames making sure to have an extra few inches on both of the frames in case you end up making a mistake.

Step 2 - Cut Lower Rails

Use a steel cutter to cut the lower rails to the determined size from your design. Then, lay them out and then use the welder to attach them to the metal engine plates making sure that you are leaving room for other attachments that the engine will require like seating bolts.

Step 3 - Weld Yoke

Now you can weld the yoke section with the lower rails. Then you can use the welder to attach the two yoke sections to each other with a brace plate, then weld the steering tube to the yoke and the frame. Make sure as you go through this step that you are leaving room for the steering rod that will go through this section.

Step 4 - Fit the Bars

Now you will need to cut out the center bar using the steel cutter. You can fit this center bar to the steering yoke and then weld them together with a support brace. Use a measuring tape to make sure that the wheel will be able to fit between the bars before you weld.

Step 5 - Set the Braces

Next, use the steel cutter to make a brace and then weld it on top of the rear side tubes which are located behind the engine block. Then you can weld the cross braces to the side tubes. Then, weld together the lower rails with the main support.

Step 6 - Weld Extras

You will need to weld any extras that you have onto the frame. First you can weld on the rear axle assemblies, making sure to measure for both of the back wheels before you proceed. Then you can move on to the gas tank or rear shocks if you choose to add those at this time. Measuring these all out in the frame rig is the best idea. Then, you can fit your axle carriers and gaskets for your steering equipment. Make sure that you are testing them out and measuring to make sure that everything fits before welding.

Once you are finished you can test everything out and then use auto paint to finish the exterior how you like it.