
It’s the end of the year. There’s no time left (;∀;)
While saying that, I’m progressing at my own pace!
With the Yoshimura ST-1 cam, I want to unlock the true performance of the oil-cooled 1200
(wishful thinking)
“The engine speed and vehicle speed keep up with each other”
That kind of image makes it easier to understand.

I removed the head cover!
The Inazuma 1200 is somewhat difficult to maintain.
●GSF1200 > GS1200SS > Inazuma 1200 > Bandit 1200 ×
I think that’s the order.

The Yoshimura ST-1
feels more like a standard cam than a high-lift cam
Due to various regulations,
it unlocks the performance that was suppressed
with a “wow! Oh yeah!” kind of double satisfaction feeling
With the stock carb, the added performance is a really tasty part.
In my imagination, I think in the future cams will become ground cams
I believe.
Ground = Cost UP = Price UP
When you look at Kawasaki cam prices, you’re amazed.
The price hasn’t changed much in nearly 30 years
*It has gone up slightly.
I want to install a cam someday!
If you don’t take action, you’ll never be able to install it~

The front slider is replaceable.
The rear is fixed to the case
and can’t be replaced without disassembling the engine.
The rear doesn’t have as much load, but it can only be replaced at times like this.
It’s one of those “while parts are still available” situations.


It’s quite worn down and stretched.
It’s interesting when you compare them~
New ones are so smooth you can dig your fingernail into them.

The cam was in beautiful condition (*´ω`*)

Clean cam = Clean rocker arm
The cam and rocker arm are like a married couple
New ones are more reliable, and when rocker arms wear out,
you can sometimes get a “tapping noise” that can’t be eliminated by adjusting the valve clearance.
Replacing them as a set is best! That’s the way to go~

The front of the exhaust was discolored from heat.
I wiped it off somewhat.
I think there was probably a time when it went through some thermal stress.
That’s what I believe.

G/K on the tensioner side. Hehe
Hundreds of times easier than the cylinder side
Everyone prefers easier work.

After installing the camshaft, it’s all about adjustment
Since it’s basically a bolt-on cam, the work is super fast.


Let me check the valve timing.
Yoshimura products are very well made, so sometimes they’re OK as-is.
Since I’ve made the sprocket adjustable with elongated holes,
I install it as close as possible to Yoshimura’s ideal values.
And that completes the cam replacement (‘Д’)

One subtle thing.
When installing the auto tensioner.
You insert the spring last and adjust it, right?
It’s good to manually adjust with a long bolt and then insert the spring at the very end.
Since this is a high-valve engine with no guide,
it’s prone to “chain skip” at the very last moment.
You want it to finish smoothly if possible.
For your reference~
To be continued.