chain hitting frame

I'm working on an '82 kz440 that was converted from belt to chain drive many moons ago. I checked the Kawasaki website and it should be a straightforward swap, but the chain is hitting the brace where the beltguard attaches to the frame in front. I put it up on the centerstand, put it in gear, and periodically the chin starts to jump around and hits the brace sideways as well as up and down. It's adjusted properly, but is literally wearing its way into the brace. I hope this description makes sense. It's got me stumped. engine sprocket problem, possibly? I'm open to any ideas. thanks
sk

You say the chain jumps around and is wearing into the brace. Is this something new, as you say the change from belt to chain was done in the distance past. If it just started I would first look at the sprockets and chains. How old are they, is it time for a new set. If so get both sprockets and a chain at the same time.

x2.

Belt guard? Is it still needed?

the bike is new to me, but from the looks of the bracket it's been going on for a while. wearing a groove into steel takes time, I would think. checking the sprockets is my next move. RE: the guard, it's the bracket that's the problem, and that's part of the swing arm.

Vertical movement on the chain I can see but side to side jumping.... :S

Something not write there in your alignments, CC sprocket to wheel hub offsets (chain path) etc....

Can you get some pictures of the area in question? Ed

I'll get a picture soon as I get home from work.

Ok, I'm hoping I can figure out how to attach a picture. After looking at the pictures in the service manual it almost seems like the sprocket(s) are too small, making the chain closer to the bracket than it should be. Anyone know what the diameter of the sprockets should be? Other than that, I haven't a clue but the chain definitely is much closer to the bracket than in the pics.

just checked the service manual. sprockets for chain drive: 216.5/64.9mm. pulleys for belt: 264/95mm. That seems like that would solve the problem, but I can't figure out why the chain sprocket wouldn't work since the swing arm and related parts are identical on the A1 and D4. I'm not that great at eyeballing a sprocket to tell if it's worn, but I'm guessing that may be it, but the chain still seems too close to that bracket to me. Ideas?

if chain is flopping side to side id guess its worn out,will removing bracket help?
have you checked front sprocket to see if its tight?

haven't checked the front sprocket yet,but will do so. thanks. the bracket is welded on so it'd be a bit of a chore to remove it, and actually I'd like to figure out what's really going on