Rare these days? GSF1200 “S Black”. Inspection, Carb OH, Oil-cooled maintenance, Yoshimura digital gauge, USB-C installation, tank rust removal and more

Three consecutive days working on the GSF 1200.
In my head it was supposed to be finished already, but it’s not going that way at all.
Overall fatigue and cleaning are taking quite a bit of time.

ヨシムラ(YOSHIMURA)
¥12,620 (2026/09/21 02:00時点 | Amazon調べ)

Today I’ll be adjusting the valve clearance (*´ω`*)

The spark plugs are burning quite well. I’ll open the PS a bit more.
DR8EA is quite a niche choice. *Originally a tip-cut JR8B
The condition isn’t bad, so I’ll reuse it as is.

日本特殊陶業(Ngk)
¥898 (2026/09/21 15:35時点 | Amazon調べ)

The camshaft seemed to be seizing a bit.
The rocker arms are also worn, so there’s some noise.
But it just keeps wearing down to become a low cam, so
considering the current mileage and future riding distance, I think we can manage.

The inside of the head was in very clean condition.

Doing some cosmetic work and subtle modifications.

Once assembled, it’s barely noticeable, but
the bolts and breather cover get cosmetic treatment before installation.

The oil passage banjo bolt gasket on the head side is replaced with a copper gasket instead of the OEM one.
The OEM gasket is aluminum with a large outer diameter and tends to collapse easily.

Using copper gives a solid tightening feel and stable retention.
Basically, aluminum tends to lose torque over time and cause oil seepage, so this is a slight countermeasure.

Using liquid gasket on the head cover side makes cleanup extremely tedious.
Without a micro rotary tool, you have to scrape it off bit by bit.

ナカニシ
¥115,775 (2026/09/20 16:33時点 | Amazon調べ)

Getting a new intake manifold while they’re still available

It’s definitely a problem when parts go out of production.
However, the GSF 1200 shares compatible parts with the GSX-R 1100K/L, so it’s relatively safe.

On the other hand, the Inazuma 1200/GS1200SS is more concerning.
The Bandit 1200 had gray imports and a long production run, so it’s somewhat safer

Oil-cooled engines have different intake manifolds for each model, which is quite a bottleneck.
I wonder if they handled the carb pitch and bore diameter issues with the intake manifold…

Using Alcan Hands for the throttle cable

It might be rude to say, but
I’m grateful that they stock throttle and choke cables for rare bikes like this.

The ferrule end is slightly wider than OEM, so it’s a bit tight to install, but it works fine.
Since OEM parts are discontinued, please use products like these.

バイク用品はとやグループ2号店
¥5,620 (2026/09/22 15:35時点 | 楽天市場調べ)
株式会社ヒロチー商事 楽天市場店
¥3,179 (2026/09/22 17:35時点 | 楽天市場調べ)

Carb hard to fit? From the air cleaner side

The air cleaner duct tube is hard to fit, isn’t it?
Since we’re reusing the duct and the air cleaner box might be deformed, it can’t be helped.

In such cases, inserting the air cleaner side first makes it fit nicely, so give it a try.
I think it’s best to make the work as easy and smooth as possible.

Easy start! Perfect sync (*´ω`*)

The engine started right up and looks good.
I’ve adjusted the sync perfectly too.

The air vent hose is Honda’s pink color, which I prefer.
Hose ends that don’t catch on anything get cut at an angle.

After a customer once told me the hose came off, I started cutting them.
Honda provides various hose diameters and lengths, which is really appreciated.

株式会社ヒロチー商事 楽天市場店
¥352 (2026/09/15 21:33時点 | 楽天市場調べ)

There’s a bit more to come.

ヨシムラ(YOSHIMURA)
¥12,620 (2026/09/21 02:00時点 | Amazon調べ)
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