Miller 3 Wheeler

Miller 3 Wheeler

I’ve always liked the look of the Morgan 3 wheeler, both the vintage version and the “newly” released version. But at a starting price of ~$42000, this isn’t something I’m going to buy. I know I can build something way cheaper, and enjoy the process too! When I moved to Shanghai China back in 2011, and saw the Chang Jiang 750 Sidecar motorcycles with the opposed twin engine, I thought that it would be a cool motor to have in a similar 3 wheeler vehicle. Once I purchased a CJ 750 sidecar motorcycle in July of 2013; that thought became a bit closer. Now that I had a bike with that motor, it would be much easier to take some measurements and check for feasibility. In August of 2013, I made a very rough CAD drawing, with some very rough measurements.

morgan 3 wheeler

As I’m finishing up on some projects, and deciding what is going to be my next big project, this thought popped back in my head, and I started thinking more seriously about it. Since I’m currently living in China, and the CJ750 is in my garage, I figured now is a good time to focus on this one. I can spend my spare time in China working on the detailed CAD model, and get all of the details worked out on feasibility, and if everything checks out, then I can buy the powertrain components in China, and haul them back to the US and then start fabrication.

Components that I can use off of the sidecar motorcycle*:

*(Note: I would buy these components as I plan to bring the current sidecar back as is to the US when we eventually move home)

  • Engine and transmission (already has reverse and shaft drive)

  • Rear transaxle

  • Rear wheel

  • Rear shocks

  • Sidecar spindle@2 for front spindle assemblies

Major Components I need to design and build:

  • Front suspension

  • tubular frame

  • Sheetmetal body

  • Seats & cockpit

Will I build this? Well, at this point I’m not sure, as I want to get through the feasibility design, and see how that goes. Right now I’m focusing on modeling up accurate models of the Engine, Transmission, and Transaxle.

I already have plenty of knowledge on designing a custom vehicle as I built a Formula SAE race car in college for senior design. Several years later I was the advisor for that team for 3 years, and saw drastic improvement in the level of cars that were built and raced. So the design and fabrication of the vehicle is less of a concern.

An area that I’m less familiar with is the sheetmetal body. I don’t have much experience in this area, but I’ve previously been researching sheetmetal equipment like English wheels, planishing hammer, sandbag/shotbag with body hammers, and other associated tools. This is an area of expertise I want to add to my repertoire of skills, and there’s nothing like a project to make that happen.

So follow along as we embark on a new journey, a new project, and new experiences to further our knowledge of all things automotive related.

So here’s what I’ve got in Late April, 2014:

3-wheeler-4-20-2014 morgan-cj750-assembly-2-4-20-2014 morgan-cj750-assembly-4-20-2014 morgan-cj750-no-body-4-20-2014

May 8, 2014

I put together a spreadsheet to tally up some rough costs in parts.

Miller 3 Wheeler BOM 5-7-2014

Total in parts right now: $2,500!!!  This is not a complete list by any means, but it does capture the high dollar items.  I still need to add estimates for body sheetmetal, frame tubing, and a lot of little parts.

I’ve made some progress on modeling the motor up accurately so that then I can model the frame and suspension more accurately.  Its not a perfect model, but it captures the important points and dimensions for proper fit and function.  Accuracy is measured in fractions of an inch, not thousands of an inch!  So here’s some eye candy for progress:


CAD model of CJ 750 engine


I’ve been doing some work on the front suspension development, and its getting kind of lengthy, so I’m going to put that on another page.  Click on the picture of the Suspension, and enjoy.  What’s shown in this picture is a very crude representation of where I’m going with the suspension, and will get updated once I do the design work on it.

Suspension Development