Hello! I'm restoring an 20 years abandoned bike, but I found a type of headset I don't know how to open to clean and lubricate. I already cleaned the other parts of the bike and they were in awful state, just a bit of rotten grease.

What you need is a hook wrench. Pretty standard if you are in to plumbing. You can buy 'em cheap. Standard tool for any bottom bracket pre 1980.https://www.google.co.nz/search?q=ho...HRlhl4DaeKHEM:

A simple single hooked lock ring tool will work. Much like a BB lock ring tool. However these headset lock rings are usually smaller in diameter (as well as typically have an odd number of notches) so the usual BB ring tool doesn't fit well.

So a few options. Use channel lock pliers, sure some surface chrome damage will happen but that ring is covered in use. Use a Bb ring single hook tool (like Park's HCW-5) buy place a straight blade screwdriver under the tool's curved edge about 1/3 of the way around the ring to better have the hook engage the notch. Or get a proper small diameter ring hook tool (like Park's HCW-17 or the venerable Hozan double ended Lock Rink tool [aka Rock Ring tool]). Andy

See my post's comment about the different diameters of headset VS BB lock rings. Andy

THANKS A LOT. That's was just the info I needed. To be honest I even had that tool but since Im a newbie didn't knew the use and never needed until now.
Best,

Xermán
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For reference I used a tool like this and it was easy and fast.


And the bike is a Dahon Classic V vintage.

Or machine [grind] a section of steel tubing (Old sockets?) to have all of the notches engaged at the same time..

You used the exact tool you were supposed to, apparently with success.