Upgrading the look of the CT125 stem with a ZETA stem nut!

I wanted to be able to use preload, so I installed ZETA's Front Fork Top Cap Preload Adjuster, and it looked really cool, so I thought I should also replace the stem nut to match. Here, I'll show you the process of installing this stem nut on a Hunter Cub. The stem nut itself is relatively inexpensive, but it was a bit difficult to procure the right tools and get the right torque, so I'll go into detail about that.

The ZETA Front Fork Top Cap Preload Adjuster made the stem area look cool!

Originally I installed the preload adjuster in the images below. Note that it is a different part number for JA55 and JA65, so don't get them mixed up.

You can take a look at the installation process in my previous article from the below link.

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

I really recommend this front preload adjuster. It will totally transform your front suspension. In the end, the stock suspension was too weak, so I replaced it with KITACO Inner Springs, but that's a story for another article. I'm a bit on the heavy side and weigh about 85kg, which is why I changed the springs, but if you are lighter you should be fine with the stock springs. The ride quality is really great now, and it also looks really cool.

But since the preload adjuster looked so cool, it made me notice the stem nut. It looks like a standard Honda plated cap nut, but since Hunter Cubs don't have many chrome plated parts, I personally feel that it looks a little out of place. On the other hand, if you're going to customize by adding more chrome plated parts, I'm fine with it as it is.

Let's install a ZETA stem nut to match!

So here it is: the ZETA stem nut.
It is made of aluminum and looks cool. Since it's the same brand as the preload adjuster, it matches perfectly in terms of design.

When the stem nut is replaced, the hole in the middle will be noticeable, so I decided to cover it with a ZETA Stem Cap. The cap is held in place by flat springs, so there is no need to worry about the diameter of the hole. I chose black because I like to keep a low profile.

Even buying both the stem nut and stem cap, the total comes to less than 3,000 JPY. It will change the look, it's lighter (even if just by a little), and the parts are inexpensive, so there's nothing but good things.

The process and necessary tools for replacing the stem nut

When it comes to replacing the stem nut, the parts are inexpensive, but the preparation is a bit more difficult, since you need tools of a size that you really only use for this one thing.

Here is what you need for the job.

- Allen wrench 6mm
- Seal pick
- 29mm socket (for stock stem nut)
- 30mm socket (for ZETA stem nut)
- Socket handle (breaker bar, etc.)
- Torque wrench capable of tightening up to 88Nm

The stem nut itself is relatively inexpensive, but the tools will also cost a bit. Specifically, 29mm and 30mm sockets cost about 1000 JPY each.

In addition, it is important to pay attention to the size of the socket wrench. In my case, I usually use a 1/4 (6.3 sq.) or 3/8 (9.5 sq.) for motorcycle maintenance, but there is an upper limit to the size of sockets that can be used depending on the size of the wrench. Specifically, a 1/4 can be used for up to 14mm, and a 3/8 can be used for up to about 27mm sockets.

In this case, we will use a 29mm and 30mm socket, so we will need a 1/2 (12.7sq) size handle. What's more, the specified torque is 88Nm, which is quite large, so the torque wrench should also be 1/2 size. There is an adapter to convert 3/8 to 1/2, but it is hard to loosen, so I used a 1/2 breaker bar and a 1/2 size torque wrench that I use for my car. I was able to use the torque wrench I had on hand, but I had to buy a new breaker bar for about 3,000 JPY. If I had to buy a new torque wrench, the cost would be more than the cost of the parts.

As for tools, Webike has a search category for tools, so you can check there. There is also a used tools section, so you may find some unexpected bargains.

The biggest challenge in replacing the stem nut is to get the right sockets and torque wrench. On the other hand, if you have the right tools, the work itself is easy.

Replacing the stem nut

Now that we have the right tools, let's get to work. The basic flow is to remove the handlebar from the clamp and shift it out of the way. Then, remove the stem nut and replace it.

First, remove the caps on the handlebar upper holder. I use a seal pick to do this, but if you can get them off any tool will do.

After removing the caps, use a 6mm Allen wrench to remove the four cap bolts.

Once the upper holder is removed, gently move the handlebar. Now that the stem nut is exposed, the real work begins.

Use a 29mm socket to remove the stem nut. I bought a breaker bar (spinner handle) because I was already sure the stem nut was tightened very tightly. It is a reliable tool that can easily remove even hard bolts. Thanks to this, I was able to loosen the stem nut quickly.

After loosening with a breaker bar, the rest of the removal is done by hand. When the stem nut is removed, there is a hole, which can also be used to attach a smartphone mount. Since we're here, let's clean up the dirt on the stem.

This is what the ZETA stem nut and stem cap look like. Black, aluminum, edgy and cool.

After wiping off the dirt around the stem, tighten the stem nut as much as possible by hand.

Then it's time for a torque wrench and a 30mm socket. The torque wrench I usually use for motorcycle maintenance cannot tighten up to 88Nm, so I pulled out the torque wrench I use for changing tires on my car.

The ZETA Stem Nut is made of aluminum, so it might get scratched if it is fastened as is. That's where I use a little trick. For this I used a torn nitrile glove that I had left in my tool box.

Tear an appropriate sized piece off the glove and use it to protect the stem nut. You can also use the plastic packaging that the parts came in or put masking tape on the inside of the socket.

Then carefully tighten it to 88Nm.

This completes the stem nut replacement.

Let's put a stem cap over the hole. The ZETA stem cap attaches with the use of three flat springs, so all you have to do is just insert it.

This is what it looks like when the stem cap is installed. It gives off a totally different vibe, right? Now all that is left is to put the handlebar back and you're done.

This is what it looks like from directly above.

Visual comparison of stock and ZETA

Since we're at it, let's put the fork top caps back to stock and compare them to ZETA's. This is with the stock caps. The matching chrome plating does look nice.

And here it is with the ZETA Stem Nut and Stem Cap, as well as the Front Fork Top Cap Preload Adjuster.

The edgy shapes and functional beauty are great. The black color blends in with the black of the stem for a stylish look.

The area around the stem is a point that you look at a lot while riding, so the dress-up effect is great. The necessary parts for this customization are inexpensive and highly recommended. However, the tools required are a bit hard to come by, so if you are not sure about doing it yourself, you can get the work done at a bike shop.