NANA Company Spring Seat Adapter for CT125 Hunter Cub - one-handed seat opening

dmonkey · Aug 12, 2023

This is one of those "you probably don't need this" mods. When the CT125 seat is unlocked with the key turned to the seat unlock position, you need to keep the key turned and lift the seat out of the locking latch mechanism which takes two hands. Not a big deal, but if you have to set something down to free up a second hand (or if you don't have a second hand) it can be an annoyance. Not only do I lift the seat to fill the fuel tank, but that is also where I tuck away an SAE cable that I use to run a tire inflator if I find the tires to be underinflated at the beginning of a riding day. There are many solutions to this issue. You can lift the seat with your knee while the key is turned to unlock, you can add some spacers or rubber cushions that press the seat up when unlocked, or you can add springs to push the seat up when unlocked. I went with the overkill option of buying a replacement seat attachment bracket that uses a torsion spring to pop the seat up.

Product link: https://japan.webike.net/products/25695128.html
NANA COMPANY product number: NA-A06

Tools used: 10mm socket, socket wrench, axle grease, double sided tape

Everything included in the kit. Instructions are in Japanese. The QR code leads to this video tutorial of installing the seat spring adapter:

If you'd like to see the seat spring in action, skip to 9:34 in that video.

Here are the instructions machine translated to English.

One thing that differed between the instructions and video is which side the retaining clip was installed on, which doesn't really matter. I followed the print instructions which result in the clip being on the exhaust side, which is opposite the rider when you open the seat. In my opinion, it looks a bit cleaner that way. I applied a light coating of axle grease to the shaft since it's a pivot point.

Side-by-side comparison of the brackets. Note that the metal hook for the helmet lock cable is missing from the NANA Company bracket, so that functionality is lost.

The NANA Company bracket is also missing the rubber foot pad designed into the OEM bracket, which would be a pain to remove or install. It includes a different style of rubber pad instead.

Here you can see where the OEM rubber pad makes contact with the seat (note: my seat is aftermarket, but the seat pan is very similar to OEM)

Here is the rubber pad included with the NANA Company kit installed in that same space. The double sided tape on the one I received came right off of the rubber which was a disappointment, but I believe that this pad gets squished between the seat pan and the metal bracket well enough that it doesn't matter too much what holds it in place. I cut a new piece of double-sided tape to fit it and stuck it in place.

Before tightening the nuts that attach the seat bracket to the fuel tank, I tested the motion of the pivot and made sure it was lined up with the seat latch.

Here it is fully installed.

After installing it I noticed that there was some side to side wiggle on the seat when it's down. I attributed this to a larger tolerance between the seat bracket and the pivot shaft than stock, so I took the bracket off, re-installed the OEM one, and then checked the play on that one. I found them to be very similar, I just hadn't payed attention to it before. The NANA Company bracket might have a little bit more wiggle to it. I do have an aftermarket seat on my CT125 which may contribute to this, but if it does I don't think it would be much difference. Not finding it to be much worse than the OEM bracket and satisfied with the spring mechanism's functionality, I re-attached the NANA Company bracket.

If someone wants to achieve similar functionality without this replacement seat adapter, though maybe not fully popping the seat open but at least lifting it enough for it to not re-lock into place when the key is removed after unlocking it, then here are some other ideas:

1) Grind out the welded pivot in the OEM seat bracket and install a new one with a torsion spring. This would also let you keep the attachment point for the helmet lock cable if that's something you use.

CT125ハンターカブオーナーだからこそ試してみた、ちょこっとカスタム【SNSで情報ゲット!】

ホンダCT125ハンターカブのオーナーが活発に情報発信しているSNSの中から、カスタム小ネタを実際に試してみました。特にポップアップシート改造がオススメです。

young-machine.com

2) Add a conical spring to the latch point on the seat.

[ホンダ CT125]スプリング電池バネ

【パーツレビュー】ホンダ/CT125装着 | キーを捻るとシートがポコっと浮きます。バネがあたる部分が傷付くので要改善

minkara.carview.co.jp

3) Add some small pads to where the seat pads make contact with the fuel tank, adding enough height and compression that when the seat is unlocked it will pop up enough to be out of the way of the latch.