Still loved after nearly 40 years: the GPz900R! More than just passing inspection—the original Ninja’s edge is restored through “inspection and Deco-mainte”

Today’s musings (‘ω’)

My recent purchases have become almost entirely disaster-preparedness gear…. And when I saw today’s news, I couldn’t resist one-click ordering an emergency escape hammer, the “SAFE-T-SYL FLEX”.

I’d been thinking in the back of my mind for a while, “I really should buy one and keep it in the car someday,” but when you see flood news and disaster footage in real time, there’s no time to hesitate.

When a car is submerged, water pressure makes the doors absolutely impossible to open. The best outcome is never needing it, but if you drive, it’s an essential talisman you should always have on hand!

Limited-edition inspection certificate holders on sale for our first anniversary in Chiba (*´ω｀*)

Remove front and rear wheels for detailed inspection

Work-wise, it breaks down into “front and rear wheels,” “controls,” “suspension,” “carb and engine,” and “electrical”
very straightforward.
It’s not about having the most inspection items; rather, when you focus on “what works and lasts,” it becomes easier to feel the difference.

I’d say most people rarely wipe down a tire with water.
Especially since we’ve moved to tubeless.
Tires are a critical component on a motorcycle—just looking at them and wiping them down makes a huge difference in your confidence.

Removing all these tiny foreign objects gives you real peace of mind (*´ω｀*)

We check wheel and tire runout.
It’s not uncommon for a wheel to bend without you noticing!
Keeping records like this lets you look back at the history and makes it easier to diagnose the cause.

The shaft showed no runout. The right side was pretty rusty-looking.
I went ahead and cleaned it up.

We adjusted the wheel bearing preload.
In two years, replacement would be a good time.

The key to refreshing the brakes

Washing the caliper really improves seal seating.
If it’s still stiff after two or three kneads, an overhaul is the way to go.
Kneading won’t solve the root problem. If you’re going to spend time, an overhaul is the most effective and efficient fix.

We lightly resurface the brake pad surface.
As you know, the top, bottom, left, and right pad surfaces don’t actually wear evenly.
Also, on streets where you don’t brake hard, a hard film builds up on the pad surface and reduces bite.
Moderate pressure is fine—just place the pad on a flat surface and rub it gently.
When a fresh surface appears, the noise and bite change.

Small things like this quietly bring it back to life.

We completely degrease and clean the brake disc.
When you do this, “the first bite feels weak, so be careful”
—basically, you reset the pad and disc and let them bed in together, which makes them perform beautifully.

Fresh fluid also restores the lever feel.
Writing all this, you might wonder if placebo is working overtime…

Spark plugs and compression

The engine was just overhauled at a master shop and is fresh off the bench, so it’s still in break-in.
The plugs are new, so no issues there.

Cold readings like this feel great!
Once it warms up, the numbers should climb even higher. Valve seating and piston ring sealing are clearly in good shape.

We adjusted the carburettor synchronization.

Charging voltage and fuses

With Deco-mainte, we check fuses every time.
Honestly, just looking at them won’t fix anything, but… it’s a “wish for good luck.”
Electrical trouble is the scariest thing there is.

They don’t cost much. If you think it looks worn, just replace it.
Most people never open the fuse box, and that’s probably normal, but take a peek once in a while.

Charging voltage looks good.
It’s important to know how much voltage is generated at what RPM.

On a big bike, peak output usually hits around 2000 rpm.
When a regulator fails or is about to fail, voltage tends to climb with RPM.

Controls and moving parts lubrication

Disassembling and lubricating the control systems is really effective.
Levers and pedals move smoothly in both directions. A smooth throttle return feels great!

We also checked the final drive ratio, chain link count, and pivot-to-axle distance,
then adjusted the chain, lubricated it, and changed the coolant!

Now it’s ready for a test ride
*It finished last week, but rain kept us from testing it at all! Tomorrow for sure!