The main harness is both an artery and a capillary for the motorcycle. Now that the main harness has been restored, the next thing to focus on is the operation and condition of the electrical units. If we can control the electrical system, we will be able to reduce the number of problems that occur after completion or while driving. I would like you to know this fact first. Anyway, electrical maintenance is important! Simply by improving the condition, you can get good results. After the restoration, the steering wheel switch looks like a new part.
- Old motorcycle switches are easy to dismantle.
- It's not just about removing rust from the tank.
- Various screws and threads are replaced with new ones
- Anti-oxidation coating is formed on small parts
- Unused switch but harness is replaced
- Operation check with single parts
- Mechanical horn depends on adjustment
- Finished with cover repair and paint
Old motorcycle switches are easy to dismantle.
The steering wheel switch is a part that was removed from the motorcycle that was falling apart. As for the right switch, I was able to get a new unused part. You can compare the left and right switches in the above picture. The disassembled switch is barely reusable! So I took it completely apart and started by removing rust from the internal parts. Unfortunately, the switch design and the inside parts of the later series models were different in design and not interchangeable.
It's not just about removing rust from the tank.
The steel inner parts inside the switch were rusty, but the wall thickness was still there and there was no rot. So we used the secret weapon for rust removal! Hanasaka G Tank Cleaner. I diluted the chemical with 10 times hot water and soaked it overnight in a container with the bottom of a plastic bottle cut off. It succeeded in removing rust and rust prevention.
Various screws and threads are replaced with new ones
In the early 60's when this Yamaha YA5 was developed and produced, the old JIS standard was used instead of the JIS/ISO standard, so the "pitch" of bolts and screws below M5 was different. If you go to the screw section of a major home center, you will find more products of the old JIS standard on the store shelves in recent years than before. Is this a trend to fix and use industrial products from the Showa era?
| ISO standards (current) | old JIS standard |
|---|---|
| M3 P=0.5mm | P = 0.6mm |
| M4 P=0.7mm | P = 0.75mm |
| M5 P=0.8 mm | P = 0.9mm |
| M6 P=1.0 mm | M6 is the same pitch. |
The parts inside the switch are rusty and corroded, but the Hanasaka G has created an oxide film on the iron parts. This was the time when the bands that held the cords in place also used minus heads. I can see the future if I come this far!!
Anti-oxidation coating is formed on small parts
The upper side holder incorporates a blinker switch. The lower side holder has an integrated clutch lever holder and incorporates a horn switch. The grounding of the switch part is important for the horn operation (resonance sound). All the wiring cords were rewired with the same color and size cores, and the protective tube is the same vinyl tube as the original manufacturer.
Unused switch but harness is replaced
The right side handle switch (light switch) is an unused part that I found at an internet auction. The unpopular model was easy to buy because there was no rival in the auction. New inner parts are very reliable and safe. The new switch has been tested with a tester. Even if it is an unused part, all harnesses have been replaced with new ones.
Operation check with single parts
I removed the lid of the stock horn and tried to connect the terminals directly to the battery. But unfortunately, the horn did not sound. So, I worked on each component with the handle of a screwdriver, and all of a sudden, "Bleep! Suddenly, it started to sound. I thought I could fix it, so I cleaned up and adjusted each part, and it started to sound perfectly!
Mechanical horn depends on adjustment
The mechanical horn comes with an adjusting bolt that adjusts the positioning of the resonating plate. In the case of this old-style spiral-type horn, there is an adjusting bolt on the inside after the cap is removed, and by adjusting the gap with the bolt, the way the horn sounds changes.
Finished with cover repair and paint
The horn cover is just a snap-fit and was easy to remove. By repainting this cover, it will look and sound better. The black paint was peeling off, so I used a wire buff to remove the old paint.
After removing the paint with a wire buffing tool, I used a hammer in a vise to push up the concave area and hit it flat. After this, I used sandpaper to make the concave part smoother and then finished it with paint.
- Point 1: It is easy to revive the switches of old motorcycles by disassembling and polishing the contacts, but be careful not to lose the small parts.
- Point 2: Soak the rusty switch parts in high-performance rust-removing chemicals to form an anti-corrosion film on the surface of the parts while removing the rust.
- Point 3: The condition of the harness can be made the best by re-tensioning. However, please be careful about the soldering of the switch contact.
- Point 4: Since the mechanical horn often doesn't produce sound or doesn't sound due to dirt or corrosion, let's give the body a steady vibration.
Modern motorcycles are overwhelmingly made up of plastic parts. The same is true for the handlebar switch; the housing itself can be disassembled with relative ease. From there, however, it is difficult to proceed unless you understand the structure and the combination of parts. Disassembly itself can be quite difficult, as you may break the claws or damage the parts that are normally stuck. On the other hand, many steering wheel switches for old motorcycles have a simple and clear structure. They are usually not waterproof, so when you open the switch, you will be surprised! The inside of the switch may be rusted red, or there may be traces of unidentified organisms that have hatched.
As I imagined, the small parts of this steering wheel switch were rusted. Even so, we decided that we could reuse it. Considering the future condition, we decided to remove the rust from the small parts. Gasoline tank rust removal chemical is very effective to remove rust from such small parts. After scrubbing the rust-affected area with a wire brush, put the parts in the bottom of a cut PET bottle and pour in the rust removal chemical for the tank and soak it. Of course, you can also use a brush-type rust remover, so it is better to proceed with the work keeping in mind the prevention of corrosion in the future.
Screws and bolts are used to tighten the parts, and we would like to replace such screws with new parts. In the case of old motorcycles, there are many cases where screws of the old JIS standard are used, so be especially careful with models made before 1965 (1965 or earlier). There are some differences in the timing of the changeover among manufacturers, but if you feel "reluctance" when you try to tighten the screws thinking that they are the same thickness, it means that they are the same diameter. However, if you feel reluctance when you try to tighten a screw thinking it is the same thickness, suspect a different pitch of the same diameter. In particular, M5, M4, and M3 screws are often used, so be careful.
When you do maintenance on a mechanical horn, use a lead wire to connect it directly to the battery and see if it makes a sound or not. It is good to check it. The old type horn this time had the resonance plate adjustment bolt on the inside of the cover, so I removed the cover and practiced the adjustment work. However, the models after 70's have the adjustment screw of the Phillips screw on the outside of the main body, whether 12V or 6V, so the strength of the resonance sound can be adjusted by turning the screw. When there is no sign of sound at all, tap the horn body with a small hammer or screwdriver handle to check the condition. In many cases, rust or dirt may be caught in the resonator plate or switch contacts, preventing them from vibrating or energizing. If there is no sound, try "knocking on it". Also, if the horn itself is in contact with other parts (such as the clutch cable), it is difficult to produce sound, so you should review and change the cable routing.
