Chain replace

I have 13,800 on my SX. Original chain & front sprocket.
Bought a new chain & idler sprocket as well as the front sprocket & chain guide.
Well to my surprise the front sprocket looks new! The idler is worn more on one side than the other. Replaced the chain, idler & chain guide but left the front sprocket. I have 2 sets of wheels & 2 JT steel rear sprockets. Didn't need changing.
But what I did notice is that with the center on the JT being slightly larger than the hub it does not sit correctly with just the mounting bolts. So the new chain ACTS like it has tight spots & loose spots!
To get it to adjust somewhat correctly it is correct on the tight spot but VERY loose on the loose spot.
It didn't seem to bother anything in the 13,000 miles it was on.
But I did order a new Supersproc sprocket for it.