06-19-2015, 10:39 PM
I also would recommend checking the TPS sensor position as someone else suggested. It is a 3 wire potentionometer which has a 5 volt reference signal provided by the ECU. It's function is to let the ECU know what type of load the engine is under along with the MAP sensor. Under conditions of light load and high manifold vacuum ignition timing is advanced as the flame front travels slower. On both my bandit 1200 and Bonneville the TPS was out of adjustment. Not sure on the CB but on those bikes just losen 2 screws and rotate the TPS. Made a nice improvement in off idle response.
O2 sensors today seldom go bad. It is a long shot but an exhaust leak can cause what is called a false lean reading. As the exhaust pulses pass the exhaust leak the resulting low pressure zone will pull in fresh air. The O2 sensor will see this and send a low voltage signal to the ECU. To check hook up a multimeter to the O2 sensor and use propane to see if the voltage signal consistently stays above or below .5 volts. This is the shade tree method but I never could justify the 5 grand for a 5 gas analyzer. You want to use the pre cat O2 sensor for this.
Good luck. Drivability issues can be maddening but it is fascinating I think to try and figure out the issue and very satisfying when fixed.
O2 sensors today seldom go bad. It is a long shot but an exhaust leak can cause what is called a false lean reading. As the exhaust pulses pass the exhaust leak the resulting low pressure zone will pull in fresh air. The O2 sensor will see this and send a low voltage signal to the ECU. To check hook up a multimeter to the O2 sensor and use propane to see if the voltage signal consistently stays above or below .5 volts. This is the shade tree method but I never could justify the 5 grand for a 5 gas analyzer. You want to use the pre cat O2 sensor for this.
Good luck. Drivability issues can be maddening but it is fascinating I think to try and figure out the issue and very satisfying when fixed.