Intermittent Brake Warning after battery failure
I have a 2002 K1200LT with 36K miles on it. Last week it would not crank due to a failed battery. I replaced the battery with a Yuasa YT19BL-BS. The bike now cranks and starts very enthusiastically, but I will often get a brake warning shortly after turning the ignition on.
The exact sequence is as follows:
1. Turn key on
2. Triangle light comes on and brake failure light flashes at approximately 4 Hz
3. Servo motor initiates test
4. During a good sequence servo sound stops after half a second, triangle light goes out, brake failure light flashes at 1 Hz
5. During a fail sequence, servo sound continues, triangle light stays on, brake failure light flashes at approximately 4 Hz
From my research this indicates that either the front or rear brake system has failed.
I have checked, cleaned, and tightened the battery connections. With the key off, the battery voltage is at approximately 12.6V. Key on 12.45V. During the servo test, the battery voltage drops to about 12.3V.
I seem to get the failure about half the time when I turn the ignition on. It also seems to occur more frequently after the bike has sat even when on the tender. I occasionally seem to get only residual braking when I get the failure indication, but not always.
For reference, I replaced the brake lines with Speiglers last year at which time the entire system was flushed and bleed. I have not had any trouble with the brakes until after the battery was replaced. I know that the Odyssey battery is the one most recommended on this forum, but I have never gotten any motorcycle batteries to last more than 2 years except for the Yausa's.
Any suggestions on how to troubleshoot this? Do I need to measure the voltage at the servo motor? What is the best way to do this?
The failed battery had a strange failure mechanism where it would charge to a normal voltage, but quickly discharge to just a few volts as soon as I turned the ignition on. Could this have damaged the servo motor?