What's with the little threaded hole?

[Gcraay]

So I have 2 swing arms. One disk, one drum. The drum has a threaded hole on the bottom, the disk on the top. I thought a Zerk fitting, but that's a big space in there, and the swing arm pin has a Zerk built in. What's it for?

Also, they both have an indent on the side of the arm near the pivot point. I first thought dent! But both? Is it for clearance?

 

[DogBunny]

The indent is clearance for the brake pedal pivot shaft, it's normal, they all have it.
The threaded hole is for the chain guard front mount, it's on top on both swing arms, you're just holding the drum swing arm upside-down.

 

[fredintoon]

Hi Gcraay,
what DogBunny said about the swingarm.
Now look at the convoluted path that grease has to follow to get from the Zirks at
the ends of the pivot bolt to between the bearing sleeve and the swingarm bushings.
What I did was tap an M6 hole in the swingarm crosstube and screw in a 90º Zirk fitting so the grease goes straight to where it needs to be.

 

[Gcraay]

The indent is clearance for the brake pedal pivot shaft, it's normal, they all have it.
The threaded hole is for the chain guard front mount, it's on top on both swing arms, you're just holding the drum swing arm upside-down.

Thanks, that helps explain things.

 

[Gcraay]

I've seen that before, I am thinking about doing that?