SR-150 YAMAHA Street Tracker

Custom industrial design motorcycle Photography tracker Transportation Design yamaha

Overview / Jun, 2018

This is a personal project that I have been longing to have since the first day I have this bike. I bought this 1992 YAMAHA SR-150 at the age of 18, which is the legal age to ride in Taiwan. I always want to design a street tracker with a performance racing tire so it has both good dynamic of controlling on road and the retro looking of race tracker.

The overall design is almost building on top of the process, I cut down the back of the chassis before any planning. All I know is I want something that looks retro but with modern parts. I learn how to work with metal and tig wield in this project. I would like to thank and shout out to 1996 custom and my friend, Alex Chen. He supports me with technical skills and the workshop so I can finish the project that stuck in my head for many years.

Inspired by Flat Tracker

Modern street trackers can trace their ancestry to the AMA Grand National Championship racing series. During the 1960s and 70s the series was the premier motorcycle racing championship, and many of the events took place on dirt ovals of varying lengths. Those racers loved their bikes and wanted to ride them on the streets as well, so modified the racers by adding lights, mirrors, a horn, front brakes.

- Flat tracker (retro)

- Modern parts (new school)

The basic concept for the whole project is to take out the unnecessary factory parts and minimize the components.

After couple sketches, I prefer the sketch on the top left. The idea is to keep the seat structure simple and make it tilt up at the end. This sketch considered having enough space for two people, but also make passenger's central gravity closer to the middle when sitting.

My focus of this project is the head light, I enjoy the simple look of the flat plate that was usually showing the rider's number in the track race. In instead of having a big round light, street tracker applies the head light into the plate, so it is street legal. By moving the regulator to the front for better cooling efficient, more importantly, it adds a little aggressive mood.

The metal piece for the front was laser cut from 4mm stainless steel. The mounts for the head light were hand cut and tig weild after since the laser cut piece is only limited to 2D surface unlike CNC part.

Signal light is integrated with the daytime running light (two strip on the right). The reason that I can put them in parallel is because the LED runs to the direction when it's on the signal mode.

Before seeing this old oil tank (forgot which model), I was thinking the bike should paint in completely matt black and embellish with vivid yellow to establish a futuristic looks. However, I appreciate the idea of "modern classic" which tell its own story and personality, and most importantly, it cape with performance that fit today.

Integrated light is always the style that I have been pursue for.

Troubleshooting

I was having a difficult time to make the tail tilting up. I figure that the round tubes have to be cut perpendicularly so they could have same amount of surface to connect. The tube bending technique couldn't be applied in this case because the angle was too tight and sharp. Eventually, I reached out some experts and did couple testing models. And I found a solution to cut down four individual tubes on the bending section in order to get the right angle. As the result, I spent most of my time to this part over the whole project since this was my first time to learn how to wield a round tube.

The rear suspension is set close to the engine and have enough space for carburetor to fit in. So that the weight distribution is closed to the center and more compact.

The tire is 150/55/17 out back and 110/70/17 up front. Front tire is thinner than the back, which give a agile handling in the corner whlie the back wheel is wider and gives a more steady riding quality.