Rough Running After Warmup

[Highmillr]

I'm having a problem with my Hayabusa 2005 limited-edition. When the bike is cold it runs great . I start it up... idols smoothly ....
after about five or 10 minutes when it warms up it starts running very rough until about 3000 RPM. After 3000 RPM it smooths out and runs great. It almost seems like it's not running on all the cylinders. At takeoff it almost dies unless i rev it upwards to 3000 rpms and ease clutch out.

I have replaced the spark plugs, spark plug coils , cleaned the injectors , still having the problem...anyone know what could possibly be the problem? Its been in the shop.. Franks cycles shop in melbourne fla .. For about 8 months now.. He has a parts busa hes been swapping parts on. Hes tried ECU .. Still does it.
Anyone know what the heck the problem could be????and if you do please call him because he's obviously clueless

 

[AK_Busa]

Did you find the problem and/or get it fixed? I believe i have the same symptoms and have tested/replaced the same things you have.

 

[Hayabusa Wannabe]

AK, to check all cylinders use an infrared thermometer to measure the temperature of each exhaust header pipe. A cylinder that is not firing at all will be relatively cold and easy to identify.

Problems at idle may be due to vacuum leaks or a vacuum imbalance among the four cylinders. At higher rpms the massive intake pressure can help to overcome the imbalance, thus it will demonstrate major symptoms only at low rpms. You can tune the vacuum balance following the throttle body synchronization procedure (a normal maintenance item) but leaks must be identified first or the tune will not produce a good result and everything will need to be repeated. One trick to finding any extraneous vehicle sounds is to put a medical tube to the ear and moving the other end around. This will amplify those high frequencies that otherwise cannot be heard above the engine. But the tech first has to kinda-sorta know the areas that may develop a leak and what a leak sounds like.

Guesses are good but many staple items should be checked from scratch. For example, for any cold versus hot symptoms I would measure the AC stator outputs and DC rectifier output for the case where an open circuit develops only when hot due to insulation breaking down. This tends to create a problem at very high rpms as the electrical cannot keep up, but these measurements are pretty quick and easy and should be done anyway.