If you’re a truly big fan of motorcycles, you might not be just a driver but also a creator or at least a repairer. For those interesting in motorcycle building, this post is worth to take a look. In particular, what I’m going to show you is how to build a motorcycle frame from scratch.
All the detailed steps of construction are represented in a neat, informative and comprehensive way so that you can capture all the pieces of information quickly and easily. What’s more? I will take you to a further step with how to build a brat style bike.
Once you had a frame, it’s time to create your own motorcycle. I choose the brat style bike as an example. Finally, I will show you how to build a sidecar for a motorcycle. This is even a further step, offering you a great shelter to carry goods and friends.
When it comes to choosing what styles of motorcycle frames, you first need to determine what kind of motorcycle you’re going to produce. Two most common frame styles for motorcycles are sport bike frames and chopper frames.
Among them, building a chopper one seem to be easier because many pre-made blueprints and designs are available for you to select and modify. Thus, this way is more suitable for home builders and small motorbike shops.
On the other hand, since a sport bike frame requires a lighter weight to be fast, builders have to deal with the combination of light materials such as titanium, aluminum, and carbon fibers. It’s not easy to put them together.
In addition, a chopper frame is categorized into two minor types: rigid frames and softail frames. So, if you choose to go with this frame, it’s important to check this post to recognize what the differences between a rigid frame and a softail frame.
Before purchasing any part, you need to make a detailed picture of what your frame will look like. At that point, design is essential. All the components should be taken into account. For examples, what style of the tank, how high the seat should locate, what color for each part, etc.
If you know Photoshop or any CAD tool, use it. If you don’t, there are hundreds of pre-made models on the Internet. You pick the one you like and then customize it as the way you want. Also, there is an interesting and useful web-based app that I found on the Internet, allowing you to design your bike with zero designing skill. Check it at here.
Tubing: ERW (Electric Resistance Welded Steel) is most common selection for the tubing. Chromoly (Chromium & Molybdenum) is also a good option; it’s lighter, stronger, but it costs more.
Chassis and Lugs: DOM (Drawn Over Mandrel) is a standard choice. The process of producing DOM is quite similar to ERW; it takes a further step to take out the imperfections, making it stronger.
You will need a wide range of equipment to create a motorcycle frame. Here are some basics:
According to your design, cut all the tubes and axles exactly in terms of dimension. You will deal with the steering yoke, seat post, backbone, bottom rails, and more. Note that you should leave a few inches to each part in case of fitting or even mistakes.
To create perfect and accurate welds, it’s indispensable to fit of the tubes. The matching points are called miter junctions. In a motorcycle frame, there are many miter junctions like the seat tube and the backbone for examples.
The mouth fit can be beveled or flattened depending on the types of weld penetrations. As you match two or three tubes perfectly, you will be able to weld them perfectly.
It’s time to shape your tubes. You will need a tubing bender to complete this task. For a step-by-step bending process, check this video. My guide won’t show you how to bend, but it reveals you some pitfalls that you might face during the process.
The most serious problem is dimensional errors and angle errors due to incorrect measurements. Any of these issues could ruin your tubes, so be very careful.
During the welding process, components could budge askew. Thus, to keep the position and alignment, you should use some clamps, tacks or bars to fix everything. Watch this video for how to weld a motorcycle frame.
A brat style bike is a café racer and was introduced by a Japanese custom builder called Brat Style. It has a very specific kind of seat (look like a banana). It was started originally by using a kind of skateboard-shaped seat before involving into more like a slab.
To summarize, a brat style bike typically has:
Since the process of building a brat style bike is quite similar to a café racer, this post will not show you a step-by-step guide to building your own brat style bike. You can visit here for a very detailed and complete guide for building a café racer.
What I want to show you in this post will be how to create a brat seat which the major difference between a brat style bike and a café racer. For other distinct parts like the mini-apes handlebar, the problem is purchasing them at the store, then assembling them in the quite similar way as a café racer.
1. Cover the gaps on the frame rails with the cardboard.
2. Cover the cardboard with the adhesive tape. Go from one side of the rail to the other side. Two adjacent pieces of tapes should be partially overlapped to make sure there is no gap.
3. Cover the adhesive tape with the aluminum tape. This kind of tape helps to keep the resin from sticking to the cardboard.
4. Cover the aluminum tape with multiple layers of fiberglass cloth (about 5). Resin will be the sticky material to attach the tape and cloth.
Note: Another way to create a seat base is using a skateboard (like an old-school style skateboard) or some pieces of flat wood (about 3). I suggest you use wood because this way allows you to fit the frame rails easier.
Just place them onto the frame rail, put some piece of carboards above and stick them together.
1. Draw the template of the seat onto the foam. The shape of the template must fit the seat base. The size of the template should be a little bit wider and longer.
2. Cut the foam based on your drawing with a bread knife.
1. Stick the underneath surface of the foam and the over surface of the seat base with super glue.
2. Wait for the glue to dry completely.
Cover the foam surface with a piece of leather. You should choose thick leather. And of course, it must be waterproof.
It’s time to move on the most difficult part, which requires both sewing skill, meticulousness, and patience. Stitch every 2 inches or so.
Every plan should be started with a detailed design or blueprint. You can use either papers or a CAD tool (such as Photoshop or AutoCAD) to draw the frame.
Some considerations that you should think carefully before and while sketching the sidecar frame for your motorcycle:
For a very detailed guide on how to design a sidecar using CAD tool, you can refer here.
My choices are:
According to your design, cut all the tubes and bars exactly in terms of the dimension. You will deal with the ‘S’ bend, swinging arm, pivot plates, ring-rolled hoop, and more. Note that you should leave a few inches to each part in case of fitting and even mistakes.
In a sidecar, there are many miter junctions like the frame underway and the dome for examples. The mouth fit can be beveled or flattened depending on the types of weld penetrations. As you match two or three tubes perfectly, you will be able to weld them perfectly.
It’s time to shape your tubes. You will need a tubing bender to complete this task. The most serious problem is dimensional errors including incorrect measurement and angle errors. Any of these issues could ruin your tubes, so be very careful.
During the welding process, components could budge askew. Thus, to keep the position and alignment, you should use some clamps, tacks or bars to fix everything.
Once again, you will need to weld a lot. Typically, there are 4 mounting points that you need to handle respectively. They are lower rear mounting, lower front mounting, top front mounting, and upper rear mounting.
The bodywork should be thick (about 1.5-2 mm). Also, it should be made of aluminum for shaping in an easy and flexible way.
There are 4 panels that you will need to create.
I hope this guide able to thoroughly solve your questions: how to build a motorcycle frame from scratch, how to build a brat style bike, and how to build a sidecar for a motorcycle. If you have any question or suggestion, please leave it in the comment section below. Thank you so much for reading!
My name is Leroy L.Simmons. I create this blog as the way to find out my excitement and also a way to remember my father. I always love writing, I embarked on this adventure of the blog, to tell you all that I want to share about my hobby, my dream of auto, truck and journey. At MRVEHICLE.NET, I hope to tell you great stories and especially to answer some questions you might ask. And there are also many interesting and up-to-date stories of drivers on their journey everywhere in the world.