1990 CG125 — meshamoto
Design, fabrication and mechanical development of my first custom motorcycle.
Bought as my first motorcycle, this 1990 Honda CG125 became the foundation of my practical mechanical experience. By maintaining and riding it regularly, I learned to recognise developing faults, work methodically, research unfamiliar systems and understand how individual adjustments affect the motorcycle as a whole.
Starting point
The CG125 began as a standard, usable motorcycle rather than a finished project waiting to be rebuilt. Whilst It only had just over 3000 miles on the clock, my initial priority was to understand its condition, establish a mechanical baseline and become familiar with the routine checks and adjustments required to keep an older motorcycle operating reliably.
As my confidence developed, I began making carefully considered changes to its riding position, appearance and usability. Each change was evaluated through real use and practical impact rather than treated purely as a visual modification.
This addictivley meditative process has brought the bike through a few different faces over the course of just the first year of having it.
The work in context
This project taught me that form and function are not separate decisions. A change to the seating position affects the bars; the bars affect cable routing; cable routing affects the wiring; the wiring affects how easily the motorcycle can be maintained.
My experience in digital design and later in an automotive workshop has made me increasingly aware of the value of a resolved system. Good work is not just about the visible result. It is about fit, sequence, serviceability and whether each decision still makes sense once the machine is back on the road.
Reworking the form
The first stage was about proportion. I reduced the visual clutter and worked towards a more compact silhouette, using the tank, seat, handlebars and wheels to establish a clearer line through the motorcycle.
The intention was not to imitate a particular period machine exactly. It was to make a small-capacity Honda feel purposeful in its own right: light, simple and visually resolved.
Electrical and fuel systems
The wiring loom was rebuilt to suit the new layout, using new crimps, soldered connections where appropriate and multimeter testing to check continuity and function.
The original carburettor was fully cleaned and rebuilt using an ultrasonic cleaner and rebuild kit. The main culprit of faulty running was the heavily corroded accelerator pump, but once renewed and all specifications set as per the manual, the bike ran perfectly!
Rebuilding the engine
The engine was stripped down completely and rebuilt from the crankcases upward.
The cases and components were vapour blasted before reassembly. I fitted new bearings and seals, along with a new OEM cylinder barrel and piston. Rebuilding it made the motorcycle far more legible to me: the gearbox, crankshaft, lubrication routes and valvetrain stopped being abstract ideas and became parts of one working system.
It was also an exercise in patience. Cleanliness, assembly order, correct torque and attention to small details.
The engine was stripped down completely and rebuilt from the crankcases upward.
The cases and components were vapour blasted before reassembly. I fitted new bearings and seals, along with a new OEM cylinder barrel and piston. Rebuilding it made the motorcycle far more legible to me: the gearbox, crankshaft, lubrication routes and valvetrain stopped being abstract ideas and became parts of one working system.
It was also an exercise in patience. Cleanliness, assembly order, correct torque and attention to small details mattered more than speed.
Current form
The bike has been a test mule for lots of maintenance, modifications and now electronics development. I've ridden over 3000 miles In the year that I have owned it (as of July, 2026) and it has never missed a beat. It has been a perfect introduction into motorcycling.
Mesha Instruments
Mesha is an ongoing instrument project designed around the CG125. The idea is to create a compact ESP32-based display using a three-inch touchscreen, bringing together essential motorcycle information with a more considered digital interface.
It is a continuation of the same thinking behind the bike itself: make the system useful, make it clear, and make it feel as though it belongs to the machine rather than being added afterwards.
