Exhaust pipe clamps

[Zmeans1]

Hey just scored on a new gz250 01 first bike love it. It runs great but where the pipes connect to the cylinder head the guy I bought it from used jb weld on left when sitting on the bike and the other (right) one is missing. I am going to replace them but you think this could cause cylinder problems? Also I got a little backfiring when declerating. I got just a little dirt on the header but and a little oil but very very little oil. Bike runs great just want to keep it cherry. Thoughts about this. Also while I got you real lose shifter.

Zac newest gz family member 6 days riding

[OldNTired]

Hey just scored on a new gz250 01 first bike love it. It runs great but where the pipes connect to the cylinder head the guy I bought it from used jb weld on left when sitting on the bike and the other (right) one is missing. I am going to replace them but you think this could cause cylinder problems? Also I got a little backfiring when declerating. I got just a little dirt on the header but and a little oil but very very little oil. Bike runs great just want to keep it cherry. Thoughts about this. Also while I got you real lose shifter.

Zac newest gz family member 6 days riding

First, welcome to the Forum!
But, I'm not sure what exactly you are asking, or what parts you are talking about! Is there any chance you can post a pic or two to clarify?
Are you saying that one of the retaining rings is missing, and on one side the PO JB welded the pipe to the head? Wow. If that is the case, you have a lot of work to de getting that JB weld off without damaging anything.
As to damage, it depends on IF the setup is leaking, how long it has been, and how hard the engine has ben pushed. If the exhaust has been leaking badly there might have been damage to the valves, and maybe even the head. And, this leak (if it is leaking) could be causing the backfires. Post pics, or at least download the manual, and let us know exactly what parts you are asking about.