Back off any top cable adjustment which will be near the twist grip on the cable. Then take up any lower cable play on the adjuster on the cap. take it up to just a little play by feeling the cable up & down within the adjuster. You might need to lift any cable black plastic cover to feel the play--just a few mm, just some play. Then could adjust the oil pump cable to align the marks. Then take up any remaining play but leave a little play at the top adjuster at the twist grip. Need a bit of play as things can alter just turning the steering lock to lock. Sometimes someone might've squashed the lower adjuster so its grabbing the cable & can't feel positive play easily.

Yes simply replacing the throttle cable isn’t bolt it on and go. All three adjustments must be made as RT325 has pointed out. If oil pump cable isn’t adjusted properly you’ll end up with bigger problems.

you might want to find manual in the tech library.  The three adjustments are in a particular order so that the carb and oil pump and twist grip work together properly.  Once you go thru the process it should work great unless something is binding.  I also like to save old cables if possible by hanging them vertical and freeing them up nicely with WD40 and then some light oil

Just a thought--you haven't screwed the throttle stop screw right in by mistake as that'll take the revs up enough when it starts to wake you up. So clunk of the slide hitting the bottom is with the speed screw backed way out so slide isn't contacting it & will clunk on the body when bottoming.