THE “Old Bike Baptism”—A Story of Wanting to Ride the Coveted Z1R Smoothly?

The long drill finally arrived!
These days, you can find affordable options on sites like Monotaro, which is a lifesaver.

The world is enjoying a three-day holiday! With deliveries and incoming bikes, I can’t work all day.
I’ll remove the broken bolt whenever I get a chance.

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If you start drilling right away, your success rate drops significantly.

I’ll make a drilling jig from a random iron rod lying around.
This time, the knock pin fits in the diameter, and the back is M6. That’s what’s broken.

So the knock pin’s outer diameter is 8Φ on the front. I’ll press-fit the jig I made into it and drill through.
After press-fitting, I’ll cut M6 threads to make it easy to remove later.
This way, I can easily pull it out later with a sliding hammer.

Proper setup is absolutely crucial for smooth work.

The crankcase dimensions are a bit tricky, so I just eyeballed it.

Please forgive any dirt.
I’ll press-fit it gently so it sits perfectly against the crankcase surface.
Then I just drill following the jig.

By creating a situation where anyone will drill straight no matter what,
you’ll almost never fail at drilling.

Then I use a long drill to gradually drill a pilot hole at center.
Of course, you have to constantly measure the depth with calipers or you’ll be in trouble.

As you can see in the image, the hole drills right through center easily.

With this crude sliding hammer made from a threaded rod, a few taps will pop the jig right out.

The satisfaction when it comes out is unbeatable! (*´ω｀*)

This time I first center-drilled with 3Φ and tried an extractor, but it didn’t work at all.
Next, I enlarged the jig to 4Φ on the lathe, then 4Φ drill → extractor, and it slid right out.
It didn’t seem to be seized and broken, so it came out surprisingly easily.

Thinking about situations like this, it’s really better to avoid stainless steel bolts as much as possible.
If the person using them takes responsibility and maintains them all the way through, there’s no problem at all, but
once you know the hassle of removing a difficult-to-machine bolt that’s broken, you can’t use them casually.

By the way, this time I was able to remove it with 4Φ, but if that doesn’t work, I’d enlarge to 5Φ.
If that still doesn’t work, I’d just tap it as M6-P1.00 as is.
If the threads are still usable, that’s fine.
But if that doesn’t work either,
I’d enlarge the hole to 6.3Φ, then helicoil tap → helicoil.

Removing even one broken bolt is a pain, and repairing the threads is quite tedious.
If you show a little love to each bolt and thread, I think the hassle will decrease.

Anyway, I’m relieved it came out safely.