Help: What's this part???

[mswitz88]

I was in the process of my first valve adjustment on my 98 Katana 600 last night and found a mystery object. I had the body stripped off, tank off, carbs and airbox off. While blowing off the bike with an air hose to remove any debris before opening up the valve cover, I noticed this little guy fly off somewhere on the bike and land on the floor. I don't know if its part of the bike or foreign material but I couldn't come up with what it is or where it goes. Anyone know? Thanks.
2012-07-17_06-46-47_956.jpg

2012-07-17_06-47-07_256.jpg

[steves]

Plastic thumb screw? not part of any kat I've worked on.

[Kreylyn]

Someone was using that to plug a hose at one time I'd guess... Probably dropped it and couldn't find later on, and it's been sitting on the motor since.

It's not an OEM part.

Krey