Before I noticed I was putting low octane gas in my bike. No big deal right but I had only used premium for 5 years. Not saying it's related but that's when the bike seemed to not run as well, and then the problems began. A few days later I was starting it made bad noise and would race up 5k rpm and back down, but only with choke all the way out. Push the choke in and it stalls. I put fuel injector cleaner in the tank and ran it for half an hour revving occasionally and things got better. But now it's back again. Sounds terrible besides the revving and black smoke and racing up and down. Then sometimes it's fine and I can race around - but I need to take care of this.