Yeah, you really should empty the tank and see what comes out when you remove the petcock.
The nut that holds the petcock to the tank is kinda unique. To install the petcock, make sure the nut is "just ready to thread" on the petcock when you put it to the tank, so both sides begin threading at the same time, drawing the petcock to the tank evenly on both sides.
You should have a large screen that covers the two straws inside the tank. That will tell you a lot of the condition of the tank.
If the original liner (dark red) is still in there, but peeling off, I hear vinegar will remove it easily. Then you will want to reline with something like POR-15.
Depending on the model petcock you have, there may be another small screen just above the outlet.
This "junk" that can find it's way down the fuel line can also get between your float needle and seat, causing fuel over flow.
Best not to use the sidestand for longer than a couple of hours, either. These bikes rest most comfortably on the centerstand.
Check your centerstand nuts & bolts for tightness. Do this about once a year!
After you push the centerstand to the ground, move your foot from the tang to the foot, itself, before hoisting the bike up. The tang will break off, eventually if you don't. If you have a later-model centerstand, it will have a bigger "tang", and you won't have this issue.
If you do have the older centerstand, you may want to upgrade. Word here is, they are easier on the back!
