I know this is a super old thread, but I am interested to know if you have solved the problem ?
Have you tried buying a new throttle cable ? They're like 17 bucks.
I have a smaller similar issue where the bike will rev to 4-5k when I turn the handle bars fully when parking the bike or doing u-turns. I am going to check the cable routing.
Weirdly, I did not.
I even bought a brand spanking new, original bandit 400 throttle cable from my suzuki dealer. The problem is the same, no matter how I route the cable.
Even when I put the cable in mid-air (no tank), the problem is there. If i tighten the cable down all the way it's better, but still there.
Btw it only happens for me when I'm already applying throttle. If you get revs with closed throttle the clearance is not right
