Hi all.. I'm new here. Sandworm from Eve Online (part of your group) sent me here for help.
Well my bike was running kinda ruff and got the air filter re charged hoping that'd help. It seemed to. then a day later I decided to try the low octane gas as someone suggested and it was a little after then it started getting this nasty vibration. See normally it gets a little ruff around 5k rpms when I think it goes from idle jets to higher end jets.. But now instead of then running smooth after then it just gets worse. It gets to the point that at 8k rpm I can't stand it and actually avoid takingit up so high. It's more of an all around vibration, seat tank, and especially handle bars. I can also reproduce this having it sit in a garage and just rev it. The only other thing I did a good few weeks back, maybe little over a month, was change my oil from the yamalube race to yamalube like 20/40w without changing the filter (long story but the filter was only a few weeks old before then, so that's why no change it).
If there's confusion on what my bike is it's a fzr400 with a 600 engine. I took the engine apart just down to the top of pistons last winter. got head job and replaced valves. don't know about the condition though of any other part in the engine, since I didn't check.
Any help.. plus if it's something serious let me know if it's the kind of thing that riding it will make it worse, 'cuz I ride daily.