Help Please! What goes here?

[FJ1200W]

Great forum, I just noticed the left hand side 90149-08255-00 is missing, now I'll check to see if the head snapped off.....

Anyone have the specific replacement size?

8mm (or resized to 10mm) and how long?

Many thanks

[balky1]

Last year I noticed I am missing that large nut on your pic and a nut from a center stand bolt. Seems common to get loose? I check them now and then from that point. Standard socket fits on them. Just enough space. But if you put larger bolt, I am not sure if it will fit.
I often notice some bolts missing or coming loose. Most often the nuts on the chain tensioners, although there is a nut and a counter-nut. One of the bolts from the mufflers came loose. The list continues.....
Just check them periodically.

[FJ1200W]

Update: I opened one of the totes of spare FJ parts, and there was a rear master cylinder in there, with the mounting bolts attached.

As luck would have it, the bolt fit perfectly.