What is that square hole doing in the bottom of the final drive?

[Lorien]

OK I have owned the bike three years and somehow never saw this. There is a square hole in the bottom of the final drive case. It appears to be in a plastic ring that partitions the sections of the cover of the final drive. Since I just saw another NT same year and model and it has one too I guess it is supposed to be there but certainly I don't know why. Anyone know?

 

[JQL]

Are you talking about the drain plug?

 

[DirtFlier]

My guess is that the square hole is some sort of casting or machining alignment point. Castings often have strange lugs/holes that don't make sense once the piece is assembled.

 

[Woodaddict]

Used as a drain hole for what water might get behind hub.

 

[Mellow]

I know on the ST1100 there's a similar hole that you can use to slip a flat head screwdriver in and help keep the spline/plate with the wheel instead of slipping off the dampeners.. just guessing.

 

[Lorien]

Are you talking about the drain plug?

No. Look further underneath the same place. This is difficult to describe but there is a plastic ring that is some kind of spacer between the rear rim assembly and the shaft drive case which connects to it. If you get way under the rear case you will see it. About 6mm by 12 mm. It seems oddly out of place as it seems it would allow road debris to get inside the rear hub unless it is some kind of drain or vent.