So, I was rebuilding my carb. I noticed that apparently the BST-40 (?) on this particular quad has I believe the pilot air screw hidden under a plug. So I drilled it out and pulled the plug to remove the screw so the carb bath wouldn’t ruin the rubber o-ring and the passage could be cleaned. All went well, except I somehow managed to lose the tiny little washer that was between the spring and the o-ring on this screw. It might have gone down the drain with the ultrasonic bath water, not sure. Anyway, since I guess no one was ‘supposed’ to be messing with this screw, there’s no part information on the breakdown on the parts sites like Partzilla, etc. So my question is, does anyone happen to know where I might find an OEM Mikuni part number for that washer, or its specs so I can grab something at the hardware store? Perhaps another bike that used the same carb and didn’t cover this particular screw? I’m a little worried about trying to just find something that seems to fit. Searching for BST-40 really only seems to return the ‘bible’ for it, without much other help that I can find.