Equipping preload adjustable front and rear suspensions on the Hunter Cub (JA55)!

I'm doing a lot of customization on my Hunter Cub, and I'm thinking it's time to touch up the suspension. Specifically, I want to make the suspension adjustable for preload. I'm not sure if it's because I'm heavy or what, but the suspension doesn't seem to be in good shape. And I want to be able to adjust both the front and rear suspension, because it looks cool.

So this time, I'm going to make the front and rear suspension of my Hunter Cub (JA55) preload adjustable.

ZETA Front Fork Top Cap Preload Adjuster for the front

The Hunter Cub's front suspension is known to be rather unreliable, but I also hear that it shapes up if the preload is adjusted. So, I'm going to install a ZETA Fork Top Cap Preload Adjuster which will make it possible to apply a preload setting to the front fork springs. Also, since the top of the fork is in view while riding, it would be nice to have a good looking part. I feel that a part that is always visible is a good place for customization.

This Fork Top Cap Preload Adjuster looks good, but it also has a full range of performance features. Not only does it allow for preload adjustment, but by loosening the air valve screw (red flathead screw), you can purge the high pressure that builds up when the forks move intensely, such as when riding in the woods, and the internal air pressure can be evened out with the outside atmospheric pressure. I probably don't need to use it for the street, but it gives a cool mechanical looking accent.

For JA55 and JA65 there are different part numbers. The one below is for JA55.

This next one is for JA65. It is hard to distinguish between them by appearance, so don't forget to check the compatible model when you purchase.

You can also replace the air valve screw with a Fork Top Bleeder. High-pressure air can be bled with a single push. The look makes me think of racing equipment for aggressive off-road courses, so it is a good way to show off your off-road style.

By the way, when you bleed high pressure air, you should do it with the front tire off the ground, using a center stand or the like. If there is a load on the fork, in the worst case you're going to have fork oil mixed in with the air that comes out.

Installation of the Front Fork Top Cap Preload Adjuster

I'm going to show the installation process by installing it on my Hunter Cub JA55. Keep the center stand out when working on it. If possible, it is best to keep the front tire in a floating position by placing a load on the rear rack or by putting something under the under guard. It is not good if the fork strokes too much due to a load on the front.

First, let's remove the handlebars to do the work. To remove the upper handlebar holder, we'll first remove the bolt caps.

Remove the upper handlebar holder with a 6mm Allen wrench.

Once the upper handlebar holder is removed, move the handlebar out of the way of where you'll be working.

Next, let's loosen the bolt on the side of the top bridge. Just loosen the bolt here, don't remove it. Also, we will work on one side of the fork at a time. In this case, we'll start from the right side.

Remove the stock fork bolt with a 17mm box wrench. It is quite tough, so be careful.

After loosening it with the wrench, carefully remove it by hand to avoid dripping fork oil. Having a rag at hand is useful.

After removing the fork bolt, the next step is to pull out the spring collar inside the fork. Again, be gentle and careful not to spill any fork oil.

The O-rings on the removed fork bolts will be used, so remove them carefully to avoid damaging them.

Install the removed O-ring directly onto the ZETA Fork Top Cap Preload Adjuster. When installing, make sure the O-ring is clean.

Place the long collar that comes with the Fork Top Cap Preload Adjuster into the fork, gently and slowly.

Next, we'll put in the small collar that comes with it.

Before you put on the Fork Top Cap, make sure you check to see that the small collar is not tilted.

Now it's time to install the Top Cap. First, carefully tighten the cap by hand. When installing, it is easier to leave the preload at its weakest, i.e., with the top side sticking out the most.

Lastly, use a torque wrench for the final tightening. The wrench size is 22mm, and the tightening torque is 25 N-m.

Finally, retightened the top bridge bolt. The specified torque is 29 N-m.

This completes one side. Once the other side is done in the same manner, reinstall the handlebars and the installation is complete.

How to adjust preload with the Front Fork Top Cap Preload Adjuster

How to use the Front Fork Top Cap Preload Adjuster... simply tighten or loosen with a 12mm wrench.

Let's see how the adjustment works. The left side of the photo below is the softest state. Tighten clockwise to increase preload. The right side of the photo shows the stiffest state with the highest preload. Even in the weakest state, the front instability is drastically reduced. It is very effective.

When the forks move intensely while riding on forest roads or off-road courses, the air pressure in the forks will increase. Turning the red part will balance out the internal air pressure with the outside atmospheric pressure. First, float the front tire and loosen the red part counterclockwise with a flathead screwdriver while holding the silver part with a 12mm wrench to prevent the preload setting from shifting, thereby releasing the high pressure air.

KITACO Rear Shock for Hunter Cub for the rear suspension

Now that the front can be adjusted for preload, the next step is the rear. The rear suspension has to be replaced entirely. The JA65 has preload adjustment on the rear suspension, so it is possible to use that stock rear suspension, but I believe it costs around 20,000 JPY for one shock. I'm going to use an aftermarket suspension because I don't want to spend almost 40,000 JPY for the stock suspension.

I chose the KITACO Rear Shock for Hunter Cub. It is sold as a single unit, so you have to buy 2 shocks, but it is cheaper than buying the stock ones!

The color is selectable from red and gray metallic. I chose the gray metallic. The suspension length is 362mm, which is the same as stock. Therefore, the ride height remains the same. The preload adjustment is stepless using two hooks. Also, the spring rate is harder than stock. If you are looking for other rear suspension products from KITACO for the Hunter Cub, they also have a high-grade suspension in collaboration with Gears.

This model has rebound damping force adjustment and ride height adjustment. I honestly wanted to get this one, but my wallet wouldn't let me.

How to replace the rear suspension

The process of installing the rear suspension varies slightly depending on the custom specifications, such as the presence or absence of air cleaner ducts and the exhaust installed. However, for replacing the rear suspension itself, all you need is 14mm and 17mm box wrenches. My Hunter Cub has a ZETA Conversion Duct installed for the air cleaner duct, so I could access the upper bolt of the left rear suspension as it is.

Use a 14mm tool to remove the nut on the lower side of the rear suspension.

The nut on the upper side of the rear suspension requires a 17mm tool.

There is a washer between the nut and the suspension on both the top and bottom, so be careful not to lose them. The upper and lower washers are different sizes, so be careful.

Next, let's carefully remove the stock rear suspension and install the KITACO rear suspension.

After attaching the suspension, insert the washers on both the top and bottom and temporarily tighten the stock nuts. Then use a torque wrench to tighten the nuts to the specified torque. The top nut is 44 N-m and the bottom nut is 29 N-m.

This completes the installation. I like the mechanical look of the monotone gray metallic, but the red color to match the Glowing Red of the body would also be nice.

How to adjust the rear suspension

Two pin spanners are used to adjust the KITACO Rear Shock for the CT125. Since we're using KITACO for the rear suspension I thought I'd also go with them for the spanners and bought two.

Use two pin spanners to control the preload by moving the two lower adjustment pieces up and down. To match up the left and right adjustments, it is standard practice to measure the length with a ruler. The initial state is quite good, but it depends on the rider's weight and riding style, so adjust to your liking.

In conclusion

Now that I can adjust the preload, I'm going to try setting the suspension. I always tighten and loosen the suspension on a whim, so I'm not sure if I'm setting it up correctly at all. I did a little research and found out that sag measurement is used as a standard for preload setting. The preload adjustment is made according to the rider's body weight, and the suspension is adjusted to a position where it can easily perform at its best. This is a standard practice in off-roading, but many people may not be familiar with it for the street. I have no idea how to do this myself, so next time I'll get someone to teach me.