There are a few unused rivnuts on my 2004 GS500F now that I've removed the fairings, etc. I want to get rid of those rivnuts and weld up the holes before repainting the frame. Is it a matter of drilling the rivnuts out, or is there a better way?

Yeesh - I can see how you're gonna have those little metallic bits in the frame holes when you're done.
I'd do this - TBH - be very very very careful, lots of issues possible with it.
OK for the first rivnut.
Grind the face and as its say 90% gone, put a bolt of the same thread but longer length in. Tighten it till it hits the opposite side of the frame and keep tightening it till it pushes the whole rivnut out.

That would now serve as your template for how big the inside of that rivnut is.
Here on out you decide if its worth it or you really wanna just put some short bolts in it and grind it flush or actually leave it with stupid bolts everywhere.

Cool.
Buddha.

I don't think pushing the rivnut out from the inside with a bolt would work so well. The shoulder of the rivnut will not easily break through the front face without deforming it. But I like the idea of putting a bolt in and tightening it till it hits the opposite side of the frame. I'll put some Loctite on the last few threads so it won't vibrate loose and then grind it all flush. Thanks for that idea.   

If the bolt is tight against the back of the frame, make sure you don't crank it hard enough to deform the back side. But by the time you grind it all flush you'd have got the rivnut loose enough that it will rattle itself and will likely fall inside the frame.

I think the vibration and shocks from the road will get it loose eventually.
However, you basically are out of many options. Its possible that Suzuki put T nuts and welded them in just 2 dots. So grind 1 somewhere invisible and try taking it out with a bolt. Its possible the thing is not larger than the hole.

Back in the day when I was doing some laser cutting stuff etc they'd put thread inserts that have that last little bit by the T part knurled. They put holes that are interference fit and just press them in. If that's the case in these, you grind the face and put a bolt in and just pull em out IMHO that's the way I'd have done it if I was building the bike.

Cool.
Buddha.

I had a good look at the rivnuts on my bike and it seems to be of the type in the picture below. If I grind the rivnut back to the frame metal, there should be a shoulder left in the hole.

If a bolt was screwed in until it touched the inside of the frame on the other side, there is no way for the rivnut to vibrate loose and fall out. I may even zap the bolt and what's left of the rivnut with an arc welder and then sand it all flush.

I appreciate your time. Please tell me if my thinking is flawed. There are at least seven such rivnuts on the frame that I want to close up.




To summarize

• Screw a bolt into rivnut until it touches the inside of frame on other side, adding Loctite to the last few threads.
• Cut off protruding part of the bolt.
• Grind bolt and rivnut flush with frame surface.
• Fill any gaps around bolt with body filler.

You don't think its that type on the upper left ?
That type you grind off the flange and put a bolt in and yank it and out it will come.
If they welded it it would likely be that type I'd guess, the pressure fit ones they use on aluminum frames like in tail sections of GSXR's of old etc.

Cool.
Buddha.

I'll grind off the welding, which funnily enough is only in one spot, and see if the rivnut can be pulled out. If not, then the bolt method will be used.