2007 R1200GS front ABS air gap too large

Hi All, I've just joined (still trial) and am hoping to find useful perspectives here. A couple weeks ago I picked up this 2007 R1200GS and noticed the "brake failure" indicator stays lit while riding. Sometimes on startup it's off, but the first time I apply the brakes it illuminates and stays lit. This particular bike has about 43k mi on it, and I'm catching up on deferred maintenance but it drives well. I've flushed front and rear brakes with fresh DOT4 but not the interconnect line, purchased the $15 Haynes manual online and downloaded the PDF owners manual but haven't yet purchased GS911 tool. In going through the steps of ABS troubleshooting from Haynes I discovered the front rotor:sensor gap is about 1.2mm instead of the prescribed 0.2-0.7mm. I've seen this cause a problem before on my 2007 Honda ST1300P after a tire change when the tech tightened axle bolts in the wrong sequence, so I checked that on my GS and it's not the problem, nor crud/corrosion between the sensor and its mounting point on the left fork leg. There are two mitigations I'm considering:

1. Shave 1mm off the axle spacer so the front wheel sits closer to the sensor.
2. Add 5 x 1mm washers between the sensor ring and the cast wheel.

The sensor bracket on the fork leg casting doesn't appear to be damaged by a disk lock, etc. Can anyone suggest something I may have overlooked and how best to fix this out-of-spec? Also, Let me know if you think correcting the air gap will solve the "brake failure" light.

Thanks!
Scott

I’d first try removing the sensor and clean its mounting base and the mounting location on the fork. Then reseat it and fasten in place before checking the gap again. I’ve seen those sensors bolted in place without being fully in position and created the problem you are having. Actually did it once on one of my own bikes when I got in a hurry buttoning things up after a tire change.

Best,
DeVern

GTRider said:

I’d first try removing the sensor and clean its mounting base and the mounting location on the fork. Then reseat it and fasten in place before checking the gap again. I’ve seen those sensors bolted in place without being fully in position and created the problem you are having. Actually did it once on one of my own bikes when I got in a hurry buttoning things up after a tire change.

Best,
DeVern

Click to expand...

Thanks DeVern! Yep, checked sensor mounting and it's fully seated and flush. I wonder if axle spacers come in different lengths and this somehow got the wrong one. It's still a mystery, but I'm thinking about riding down to Ted Porter's soon since I'm in the Bay Area and he's local.

Welcome to the forum!
Along with why GTRider advised, I like to test all possible problems before I start serious modifications. Could a spacer be in backwards?
Ted Porter has a good reputation. I don’t think you can go wrong with a visit.
Gary