
Everyone’s favorite? The Inazuma 1200 oil-cooled Katana.
I carelessly recommended the Yoshimura ST-1 cam on the blog, so now we’re overflowing with cam work… It looks like cam replacements will continue for a while.
So we’ll start with the cam replacement (*´ω`*)

Yo
shimura, right? The box looks cool… This logo and font are really excellent.


The oil-cooled 1200 series Yoshimura ST-1 cam will probably be in short supply soon.
My prediction is that after the new fiscal year next year will be a year of price increases.
When should you buy? Now, right? That’s what I think.

Let’s replace the rocker arms together.
Replacing the rocker arms significantly reduces the knocking noise.
With rocker arm type engines, it might be more the sound of worn rocker arms rather than valve noise. Rocker arm wear is a place that can’t be hidden by valve adjustment.
Be sure to do them as a set.
Arm Valve Rocker 12840-27A01



In this state we can only replace the front side, but it’s best to replace the cam chain slider as well. It’s a precious part that will definitely become discontinued.
The elasticity of new versus used is completely different.
Guide Cam Chain NO.1 08319-3110A


The oil-cooled spark plug hole head cover gasket tends to stick.
If you don’t pull it, just give it a sharp tap and it’ll come off.
It’s better to remove the gasket as an assembly to avoid trouble.
*It’s when the metal washer inside the gasket falls into the cam chain tunnel.


It’s quite heavily brown… I wish we could clean it up somehow.

All removed.



The cam is definitely seized up.
Oil temperature and oil pressure are extremely important. Especially oil pressure.
If you keep oil flowing properly, I think it’s surprisingly unlikely to happen.

Now let me quickly replace it and adjust the valve timing.

I’m cleaning the holder as much as I can.
Engine conditioner is surprisingly effective on sludge.
*Don’t spray it inside the engine.


New parts always feel good. Well, you can’t see it once the cover is on…


The cam sprocket is always set up with one set of vernier adjustment.
It’s fast with oil-cooling (*’▽’)

That said, it’s surprisingly time-consuming racing work.
I’ll set it to match Yoshimura’s settings. (#4)

Everyone’s favorite advance rotor. It’s selling!
33120-19C20 Rotor Signal
To be continued (*´ω`*)
