KX250 chain adjuster seized

I'm starting to worry.

I've got a '99 KX250. The left side chain adjuster bolt threads right out, no problem. The right side, however, is another story.

I does not thread in too well, and has now completely stopped on its way out. There's about 1" to go based on the other bolt that I've got out. The bolt does not appear bent.

The head of the bolt is virtually gone due to some ill-advised "field work." What do I do now? Drill it then clean the threads up with a tap? I'm a bit stuck and need some help. I'm starting to worry that I'm going to need a new swing arm. I was thinking I could just cut the bolt off and use a new trick adjuster. Unfortunately, the chain adjuster blocks I've seen all use the OEM threads in the swing arm.

If nobody has picked up on the clues, I'm relatively new to this whole dirtbike thing. This is a used bike that has had some neglect (see previous thread about grabby clutch and seized swingarm bearings). What should I do to prevent this in the future? Anti-seize on the bolt?

Thanks for the replies guys.

My bloody knuckles have cried uncle. That, and most of the neighborhood kids learned a bunch of new words that were streaming from my garage.

So I went ahead and pulled the swingarm off. I'm going to take it to the machine shop nearby that has done some custom work for me in the past.

So to prevent this in the future, just a bit of anti-seize when I adjust the chain from now on?