roger 04 rt
New member
Back when I had my red ‘04RT (miss that bike), I spent a lot of time working out what it takes to get a dual-spark Oilhead to start in less than a second when cold: https://forums.bmwmoa.org/showthread.php?70495-Starter-or-Battery-2004-R1150RT . Bedsides the usual suspects (fuel, compression and spark), the ‘04 bikes need a clean electrical system, a fully charged non-sulfated battery and a good starter that doesn’t draw too much current.
Fast forward to the past week: my 2001 R1150GS is turning over a bit slower than usual and takes a full second to start first time in the morning, and the starter sounds a little rough. That’s not bad but it was faster a couple years ago. On top of that I’ve had three occurrences where I get ABS errors that don’t clear after riding off (blinking in tandem sometimes or both flashing alternately other times). The ABS errors can be cleared by restarting the bike.
Yesterday I hooked up my GS-911, selected all realtime values, put the 911 in turbo mode for fast data collection, and collected a realtime log. The log confirmed it was starting okay but the voltage readings went 13V to 12.6V at key on (that’s fine) and then to about 8V for the first couple samples when I hit the starter. The 8V dip explains the slightly slower start and the ABS errors (btw, an 8V dip on a dual spark would really mess up the start).
The question is, do I have a bad battery or starter or something else?
The bike has 42,000 miles on it, the starter is original and has never been serviced, and the bell housing area shows a lot of clutch dust. The battery is a PC680, several years old, but well maintained and still holding 100% SOC even after the surface change is bled off by turning on the headlight for 30 seconds. The cables to the battery, ground, alternator and starter are tight and clean as a whistle.
I hate throwing parts at a problem so I’m going to begin by servicing the starter, we’ll see ...
Fast forward to the past week: my 2001 R1150GS is turning over a bit slower than usual and takes a full second to start first time in the morning, and the starter sounds a little rough. That’s not bad but it was faster a couple years ago. On top of that I’ve had three occurrences where I get ABS errors that don’t clear after riding off (blinking in tandem sometimes or both flashing alternately other times). The ABS errors can be cleared by restarting the bike.
Yesterday I hooked up my GS-911, selected all realtime values, put the 911 in turbo mode for fast data collection, and collected a realtime log. The log confirmed it was starting okay but the voltage readings went 13V to 12.6V at key on (that’s fine) and then to about 8V for the first couple samples when I hit the starter. The 8V dip explains the slightly slower start and the ABS errors (btw, an 8V dip on a dual spark would really mess up the start).
The question is, do I have a bad battery or starter or something else?
The bike has 42,000 miles on it, the starter is original and has never been serviced, and the bell housing area shows a lot of clutch dust. The battery is a PC680, several years old, but well maintained and still holding 100% SOC even after the surface change is bled off by turning on the headlight for 30 seconds. The cables to the battery, ground, alternator and starter are tight and clean as a whistle.
I hate throwing parts at a problem so I’m going to begin by servicing the starter, we’ll see ...