Busted Rear Shock Requires Overhaul, and Repairable Even OEM Rear Shock!

If your rear shocks are not working properly or responding well, you will not only have a hard time driving comfortably, but you may even be surprised. Rear shocks for older models often have nitrogen gas leaks, and even if you adjust the damping notch, you may not feel the linear difference you want. Even the factory rear shocks can be overhauled by professionals, depending on the model. It is always a good idea to ask if the rear shock can be overhauled or not.

Ask a professional for a suspension overhaul

Even the stock rear shocks on production motorcycles from the 1990s onwards have been upgraded to such an extent that there is not much difference in the internal structure between them and today's rear shocks," said the technician who ordered the overhaul. Using special tools for disassembly, they started to disassemble the rear shock damper unit.

Disassembly without destroying the combination → Internal cleaning

After using a spring compressor to make a single damper body, the damper rod is fixed and the upper mount and body are disassembled. Oil seals and O-rings are replaced with new parts, but all damper-related parts are cleaned and inspected. When damper rods are rusted and cannot be reused, they can be reclaimed by hard chrome plating. Bump rubber was shattered and disappeared, but this is what it looked like just before it was shattered. Technics has bump rubbers for various rod diameters, so there is no need to worry.

Replace non-reusable parts with new ones

Many inner parts were replaced on this rear shock. Naturally, all the oil seals were replaced with new parts. The overhaul fee varies depending on the model, so please refer to the company's website.

Regardless of the motorcycle season or racing season, Technics is sent from all over the country with numerous suspension overhaul requests. In addition to the rear shocks, there were a surprising number of front forks waiting to be disassembled. They are a reliable suspension specialist workshop.

Old oil is naturally black

All inner parts are thoroughly inspected and cleaned before assembly begins. Damper body and reserve tank are filled with proper amount of damper oil. It is said that many customers use oil change service regularly. This is because oil change is very important to maintain the suspension performance.

There is a variety of know-how in the assembly procedure.

Pistons and related parts assembled to damper rods are not directly assembled into the body, but are submerged in an oil jug for a while to release air. This is an important step to ensure smooth assembly and air bleeding. The pre-aired damper unit is quickly inserted into the body. The damper unit is not pushed deep into the body, but is further aired out around the top immediately after insertion. This is a very thorough process.

Fill the reserve tank with gas

Insert the damper rod unit into the body. After removing the air, push the seal head into the body and fix it with the snap ring. Adjust the height of the sub-tank piston, fix the cap and fill it with nitrogen gas. This sub-tank cap is not a valve type, but a rubber end, so you need to use a special tool like a needle to fill it with nitrogen gas. I checked the rebound of the damper by changing the damping notch.

Spring painting can be requested

Requested to paint a spring with powder coating. Powder coating is a painting method in which powder sprinkled by a special gun is melted by high-temperature drying to form a coating film. The high-performance powder coating is very tough against stones.

Even the manufacturer's stock suspension has this finish

The completed rear shock unit has a very special finish that never looks like a stock part. The springs can be finished in your favorite or original color, and the body can be treated with a surface treatment to increase the sliding performance, transforming it into a completely special product. It's a big difference from the stock spring.

Technix in Kasukabe, Saitama

This showroom beautifully displays vehicles in the process of maintenance. In short, "maintenance for show" was underway. A large vehicle with its front and rear suspensions removed was also waiting at the maintenance stand. This is a scene that can only be seen at Technics.

Cooperation photography: Technix

There must be many riders who have experienced that the front and rear suspensions are not working properly, or on the other hand, the dampers are loose and the suspensions are soft. Do you have such reviews or experiences?

From the '80s onwards, many of the semi-essential models have an air valve on the top cap of the front fork. There must be many riders who have touched that valve (out of curiosity or by mistake), and the driving impression became unpleasant compared to before. If you press the head of the air valve with your toe to release the air when the suspension is sinking even a little bit, the air pressure will become high while the suspension is sinking. This will cause the suspension to move in the direction of extension, resulting in "negative pressure" and suppressed movement. This will significantly reduce the movement of the front forks during riding and cause excessive riding vibration to be felt in the handlebar grip. When adjusting the pressure, follow the owner's manual and set the air pressure to the specified level, or push the valve to atmospheric pressure while floating the front tire.

This photo was taken at Technics, a professional suspension shop, where they were overhauling the rear shocks. Most of the high-performance off-road vehicles since the late '80s have had a separate nitrogen gas tank, and most of the road models, whether monoshock or twin-shock, have had a separate tank as well. Also, many of the damper units on high-performance models are equipped with a damping force adjustment function, even on the manufacturer's stock suspension. It should be safe to assume that almost all of the parts used in high-performance models can be "disassembled and overhauled", although they are the manufacturer's genuine parts. The stock rear shock for an off-road vehicle that was photographed here had never been overhauled or had the damper oil changed in the past, and the damper oil that came out when it was disassembled was completely black.

The bump rubber, which works at the full bottom, had completely disappeared. The nitrogen gas was also below the specified pressure, so the movement of the bump rubber was quite obvious. If the rear shock can be disassembled as reported here, it is possible to overhaul it with the manufacturer's genuine parts. According to the staff at Technics, "If the damper rods are deeply scratched or rusted, it will take time to re-plate them, but if it's just surface rust, we can polish them up and reuse them. We also stock oil seals, dust seals, and bump rubbers for each type of seal head, so unless it is for a very rare model, we can almost handle it. In this case, the springs were powder coated to enhance the originality, but this type of painting is also available. In addition, you can also order Kashima coating to improve the sliding performance of the aluminum body. The most important thing is to change the front and rear suspension oil on a regular basis, as well as the engine oil. If you are a sporty rider, you must change the oil regularly regardless of whether you are riding on-road or off-road. You will definitely feel the difference.