first take off the bracket with the tank. Most people in fact take off the tank that way because the majority of the Skorpion tanks are broken like yours.
All three of mine were and lots of others I have seen.
Go out a get some sort of 2 component resin suitable for thermoplastics - not epoxy or polyester. Over here in Germany, one is available from Würth and colloquially called faring adhesive, because that is what it is mostly used for. It is black and sets in about 5 minutes.
After emptying the tank, turn it over and carefully drill from underneath with a 1/8" twist drill slightly to one side of the captive nut. If you are lucky, you will be able to jamb that nut with the drill or a piece of rod enuf to get the bolt out. Once you have the bolt out, enlarge your drilled hole, being careful NOT to drill thru into the actual tank. Put vaseline on a new M6 bolt and turn it into the captive nut. Now get that gunk you bought and inject it into the drilled hole, turning the capive nut as much as possible the first minute or so. Inject as much and as firmly as possible. If you have air, blow into the hole after the first injection and add more gunk. Remember, most of these repair resins set very quickly so this manipulation should be done within 2 minutes or so. before it is too late back the greased bolt out and back in a couple of times. remove it just in time. Let the whole thing set long enuf and you're done. You may have to clean out the threads with a M6 tap. Filing a groove in an M6 screw is tap enuf for this purpose.
I have fixed a number of tanks this way.
The bolts get stuck because dimwits put Locktite on the bolts after they lost the first one(s). I secure the two bolts with wire in the classic manner. that way I don't even have to tighten them.
On the racers, I do not bolt the tank at all.
- tank strap.jpg (66.46 KiB) Viewed 2569 times
I think you can see the rubber strap bolted to the tank and hooked on to a allenhead bolt fixing the bracket. Of course, the two two parts of the bracket holding the rubber grommets have to be sawn as to a height just slightly higher than the rubber part the tank rests on, just high enuf to keep that center nose of the tank in position.