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[Young Machine × Yoshimura Collaboration Model] MONKEY125 Custom Project #4 Front Fork


To commemorate the 46th machine of the year (MOTY) held at the end of the last year 2018, “Young Machine” magazine and Yoshimura’s collaborator, Special Monkey 125 was born. On March 22 to 24, Tokyo Motorcycle Show 2019 was decided to be exhibited at Yoshimura booth. In addition, among MOTY voting participants, one lucky person who can get this MONKEY is decided at the venue! In this featured series, we will deliver a documentary on the production of 1 Special MONKEY to the world. The 4th is that the outer tube of the front fork is blackened with anodized aluminum.

First of all, from disassembling the front fork. Anyway, it was very hard to drain the oil.

The next process is the black anodizing of the inverted fork outer tube. Originally, the outer tube of the MONKEY is red anodized aluminum, but it was the work to remove it off and make it black with anodized.

The disassembly work of the front fork was requested by ATTRACTIVE which appeared in the 1st of this series. The structure of the MONKEY itself is more simple than a large model, but it is a difficult part that the fork oil is hard to miss anyway. If you do not follow the proper procedures, the oil remaining when pulling out the inner forks will explode into the surrounding area under negative pressure. It’s better to certainly leave it here with professional staff.

ヤングマシン×ヨシムラ モンキー125カスタムプロジェクト

It is necessary to disassemble the inner and pull it out in order to split the outer of the inverted fork.

ヤングマシン×ヨシムラ モンキー125カスタムプロジェクト

The inverted fork of the Monkey 125 is the same structure as the sibling model MSX125 (GROM), and the difficult part is that the fork oil does not slip easily and takes a long time. If it’s STD way, it’s only a little trickier.

ヤングマシン×ヨシムラ モンキー125カスタムプロジェクト

An inverted fork that had been disassembled. After this, the anodized processing was requested to KOHKEN which also supported Yoshimura.

Anodizing to improve weather resistance by coating aluminum surface

In the first place, “Anodized” is a chemical treatment that increases the weather resistance by making a film on the surface of aluminum. On the surface of the coating, there are countless fine holes, which can be dyed in various colors if the dye is infiltrated. Not to mention the weather resistance, this colorful style of fashion makes it a pleasure to anodize motorcycle parts.

I asked for the work of KOHKEN in Kanagawa Prefecture. The company’s current president, Shinichiro Ninomiya, was a motorcycle racer, and now he has the anodized factory, which accounts for 30 percent of all the work. Many of the staff members are also riders, so they know the “key points” when anodizing motorcycle parts.

ヤングマシン×ヨシムラ モンキー125カスタムプロジェクト

[Cooperated SHOP]
KOHKEN (KOHKEN 3313 Ikebe-chō, Tsuzuki-ku, Yokohama-city, Kanagawa-prefecture TEL:045-511-7333
Mr. Hayato Kuroda, who helped with the interview, was also in charge of sales of Brembo, which is handled by the company as an authorized dealer. The CRF450L of the photograph is a demo model of KOHKEN and all the new motorcycle that has not been run are scattered, and each part is anodizing.

This time the MONKEY outer tube was also used, and the re-anodizing was only applied to the outside, and the inner was applied in the direction of masking and leaving the original red anodized aluminum. When re-anodized removed the original film (= Dissolve with chemicals), the size after the finish is slightly thin because the aluminum of the original color is cut slightly. If the inside of the outer tube is thin and the inner diameter is spread out, the clearance with the inner tube spreads, and the possibility of affecting the operation of the fork is not considered.

The actual reduced size are small, but this know-how is the strength of the company specializing in motorcycle parts. You can entrust your motorcycle parts with confidence.

The outer tube of the F fork was made black with re-anodized aluminum.

Removing: Start Working!

ヤングマシン×ヨシムラ モンキー125カスタムプロジェクト

The re-anodizing can be classified into 5 steps (removing→chemical polishing→anodizing→dyeing→sealing treatment). First, remove the old anodized film. By the way, the masking part is a confidential. It had a mosaic.

Removing: Red pattern spreads…

ヤングマシン×ヨシムラ モンキー125カスタムプロジェクト

When soaked in a strong alkaline liquid, the red anodized melted and gone down.

Removing: It’s completely gone

ヤングマシン×ヨシムラ モンキー125カスタムプロジェクト

The red outer was exposed to the aluminum original color! Remove the film with chemicals, so the surface was slightly rough and glossy. If anodized as it is, it was possible to finish with a matte finish.

Chemical Polishing: Applying gloss to the surface of the material

ヤングマシン×ヨシムラ モンキー125カスタムプロジェクト

Because I wanted to be glossy this time, I performed a treatment called “Chemical Polishing” that smoothes the unevenness of the surface with chemicals and make it glossy. When soaked in a liquid, it was the glow that you see. It was interesting (Laughs)

Anodizing: Fixing to important jigs

ヤングマシン×ヨシムラ モンキー125カスタムプロジェクト

The anodic oxide film was formed by soaking it in an electrolytic solution and passing a current through electrolysis. The jig that soaked in the electrolyte was fixed so that parts do not shift during work, and it is responsible for two parts that surely conduct electricity.

Anodizing : Electrolysis in sulfuric acid

ヤングマシン×ヨシムラ モンキー125カスタムプロジェクト

It was soaked in a sulfuric acid tank and electricity was passed. Electricity flowed from the hook at the top of the jig, but when conduction stops, processing also stops, so fixing it to the jig is important. This time about 15.20 microns film was formed (changing the thickness by color shading).

Anodizing: A new coating

ヤングマシン×ヨシムラ モンキー125カスタムプロジェクト

New outer film was formed. If it was a so-called Clear anodizing, the work was until here.


ヤングマシン×ヨシムラ モンキー125カスタムプロジェクト

Next was the dyeing process. A dye bath wa prepared according to the color, and it was dipped in here and dyed the parts.

Sealing Treatment → Jet Black Fork Completed!

ヤングマシン×ヨシムラ モンキー125カスタムプロジェクト

Blackened outer tube. The red inside looked like a special part!? (It can not be seen after assembling it) the photo was a washing step after dyeing and after this, it is completed through the “sealing treatment” that closes the hole containing the dye! to be continue with<# 5 Ceramic Coat Painting> Please look forward to it!

● Photo by: Shin Matsui
*This article is restructured based on the article published in the April 2019 issue of Young Machine.

Original Source[ YOUNG MACHINE ] (*Japanese)

See Accessories of YOSHIMURA
See HONDA Moto Index Page
See Accessories for HONDA Monkey 125

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