Bank Angle Sensor info, especially for those running aftermarket ignitions
Bank Angle Sensor info, especially for those running aftermarket ignitions
NOTE/EDIT: This only applies to 1998-2003 Sportster. Pre-98 don't have Bank Angle Sensors (BAS), and post-'03 it is integrated into the TSM and functions way way different.
After doing lots of reading on forums about the BAS, I found a treasure trove of misleading info out there. Thought I would address what I found to be true in practice.
For those who don't know, carbed sporties have a sensor that detects harsh lean angles, and can shut the bike off if you drop it (sensor kills the bike at about 55 degrees of lean). From experience, this sensor doesn't always work haha. The 3-wire BAS has a ground wire, a redundant wire coming off of the stop/run circuit, and a wire that runs exclusively between the BAS and the ignition unit (this wire powers the magnets in the switch). Under normal operation, the wire between the ignition unit/BAS is grounded; if the bike tips, the sensor closes the ground and the stop/run circuit, effectively killing the bike.
Aftermarket ignition units (in my case, a Dynatek 2ki) don't have a wire out for the BAS, so the BAS will no longer function as a kill switch, and can be eliminated. No fancy wiring needed, just unplug the BAS or you could just leave the sensor there, it's no longer receiving power and can't function. If you really wanted to maintain the BAS with an aftermarket ignition unit, you could connect the wire that originally ran between BAS/ign to another closed constant 12V supply, and leave the stop/run and ground wires as-is.
If you're running a stock ignition unit and need to diagnose a faulty BAS, or eliminate the BAS (for whatever reason), you simply need to cap the stop/run circuit wire, and connect the wire that runs between BAS/ign to the ground.
Can't believe how much misinformation was out there. Wildest post was where someone confidently said the BAS acted as a "voltage stabilizer" for the stop/run circuit haha. Other than that being totally unnecessary and wrong, they hadn't even looked at the wiring diagrams to noticed that the stop/run wire on the BAS is an open circuit under normal operation haha. Can't regulate voltage on something that isn't connected when the bike is running.
Hopes this info helps someone who was getting as blatantly mislead like I was. Cheers.
*edit: Another common error I read, was people saying the BAS works with the turn signal module; this is untrue. The TSM and BAS are not connected in any way, BAS does not act as a turn signal canceller.
After doing lots of reading on forums about the BAS, I found a treasure trove of misleading info out there. Thought I would address what I found to be true in practice.
For those who don't know, carbed sporties have a sensor that detects harsh lean angles, and can shut the bike off if you drop it (sensor kills the bike at about 55 degrees of lean). From experience, this sensor doesn't always work haha. The 3-wire BAS has a ground wire, a redundant wire coming off of the stop/run circuit, and a wire that runs exclusively between the BAS and the ignition unit (this wire powers the magnets in the switch). Under normal operation, the wire between the ignition unit/BAS is grounded; if the bike tips, the sensor closes the ground and the stop/run circuit, effectively killing the bike.
Aftermarket ignition units (in my case, a Dynatek 2ki) don't have a wire out for the BAS, so the BAS will no longer function as a kill switch, and can be eliminated. No fancy wiring needed, just unplug the BAS or you could just leave the sensor there, it's no longer receiving power and can't function. If you really wanted to maintain the BAS with an aftermarket ignition unit, you could connect the wire that originally ran between BAS/ign to another closed constant 12V supply, and leave the stop/run and ground wires as-is.
If you're running a stock ignition unit and need to diagnose a faulty BAS, or eliminate the BAS (for whatever reason), you simply need to cap the stop/run circuit wire, and connect the wire that runs between BAS/ign to the ground.
Can't believe how much misinformation was out there. Wildest post was where someone confidently said the BAS acted as a "voltage stabilizer" for the stop/run circuit haha. Other than that being totally unnecessary and wrong, they hadn't even looked at the wiring diagrams to noticed that the stop/run wire on the BAS is an open circuit under normal operation haha. Can't regulate voltage on something that isn't connected when the bike is running.
Hopes this info helps someone who was getting as blatantly mislead like I was. Cheers.
*edit: Another common error I read, was people saying the BAS works with the turn signal module; this is untrue. The TSM and BAS are not connected in any way, BAS does not act as a turn signal canceller.
Last edited by templeofdank; Dec 8, 2020 at 10:58 AM.
HDF Community Team
Joined: Jan 2010
Posts: 1,256
Likes: 465
From: shore of Gitche Gumee
On my 2012 custom the trouble code came up as a faulty tsm. Since my turn signals were working properly, I over looked that code. Turns out the bas is built into the tsm module. Replacing the tsm cured my issue.
My post specifically describes the BAS for carbureted Sportsters, not 04+ and EFI Sportsters. The BAS on your 2012 functions worlds apart from the 98-03 BAS switches. Glad ya got it sorted for your bike.
Stage I
Joined: Jun 2021
Posts: 1
Likes: 0
From: Winter haven, fl
03 no spark. Possible bas malfunction?
NOTE/EDIT: This only applies to 1998-2003 Sportster. Pre-98 don't have Bank Angle Sensors (BAS), and post-'03 it is integrated into the TSM and functions way way different.
After doing lots of reading on forums about the BAS, I found a treasure trove of misleading info out there. Thought I would address what I found to be true in practice.
For those who don't know, carbed sporties have a sensor that detects harsh lean angles, and can shut the bike off if you drop it (sensor kills the bike at about 55 degrees of lean). From experience, this sensor doesn't always work haha. The 3-wire BAS has a ground wire, a redundant wire coming off of the stop/run circuit, and a wire that runs exclusively between the BAS and the ignition unit (this wire powers the magnets in the switch). Under normal operation, the wire between the ignition unit/BAS is grounded; if the bike tips, the sensor closes the ground and the stop/run circuit, effectively killing the bike.
Aftermarket ignition units (in my case, a Dynatek 2ki) don't have a wire out for the BAS, so the BAS will no longer function as a kill switch, and can be eliminated. No fancy wiring needed, just unplug the BAS or you could just leave the sensor there, it's no longer receiving power and can't function. If you really wanted to maintain the BAS with an aftermarket ignition unit, you could connect the wire that originally ran between BAS/ign to another closed constant 12V supply, and leave the stop/run and ground wires as-is.
If you're running a stock ignition unit and need to diagnose a faulty BAS, or eliminate the BAS (for whatever reason), you simply need to cap the stop/run circuit wire, and connect the wire that runs between BAS/ign to the ground.
Can't believe how much misinformation was out there. Wildest post was where someone confidently said the BAS acted as a "voltage stabilizer" for the stop/run circuit haha. Other than that being totally unnecessary and wrong, they hadn't even looked at the wiring diagrams to noticed that the stop/run wire on the BAS is an open circuit under normal operation haha. Can't regulate voltage on something that isn't connected when the bike is running.
Hopes this info helps someone who was getting as blatantly mislead like I was. Cheers.
*edit: Another common error I read, was people saying the BAS works with the turn signal module; this is untrue. The TSM and BAS are not connected in any way, BAS does not act as a turn signal canceller.
After doing lots of reading on forums about the BAS, I found a treasure trove of misleading info out there. Thought I would address what I found to be true in practice.
For those who don't know, carbed sporties have a sensor that detects harsh lean angles, and can shut the bike off if you drop it (sensor kills the bike at about 55 degrees of lean). From experience, this sensor doesn't always work haha. The 3-wire BAS has a ground wire, a redundant wire coming off of the stop/run circuit, and a wire that runs exclusively between the BAS and the ignition unit (this wire powers the magnets in the switch). Under normal operation, the wire between the ignition unit/BAS is grounded; if the bike tips, the sensor closes the ground and the stop/run circuit, effectively killing the bike.
Aftermarket ignition units (in my case, a Dynatek 2ki) don't have a wire out for the BAS, so the BAS will no longer function as a kill switch, and can be eliminated. No fancy wiring needed, just unplug the BAS or you could just leave the sensor there, it's no longer receiving power and can't function. If you really wanted to maintain the BAS with an aftermarket ignition unit, you could connect the wire that originally ran between BAS/ign to another closed constant 12V supply, and leave the stop/run and ground wires as-is.
If you're running a stock ignition unit and need to diagnose a faulty BAS, or eliminate the BAS (for whatever reason), you simply need to cap the stop/run circuit wire, and connect the wire that runs between BAS/ign to the ground.
Can't believe how much misinformation was out there. Wildest post was where someone confidently said the BAS acted as a "voltage stabilizer" for the stop/run circuit haha. Other than that being totally unnecessary and wrong, they hadn't even looked at the wiring diagrams to noticed that the stop/run wire on the BAS is an open circuit under normal operation haha. Can't regulate voltage on something that isn't connected when the bike is running.
Hopes this info helps someone who was getting as blatantly mislead like I was. Cheers.
*edit: Another common error I read, was people saying the BAS works with the turn signal module; this is untrue. The TSM and BAS are not connected in any way, BAS does not act as a turn signal canceller.
3rd Gear
Joined: Aug 2024
Posts: 7
Likes: 0
From: Kentucky
99 sporster bas
NOTE/EDIT: This only applies to 1998-2003 Sportster. Pre-98 don't have Bank Angle Sensors (BAS), and post-'03 it is integrated into the TSM and functions way way different.
After doing lots of reading on forums about the BAS, I found a treasure trove of misleading info out there. Thought I would address what I found to be true in practice.
For those who don't know, carbed sporties have a sensor that detects harsh lean angles, and can shut the bike off if you drop it (sensor kills the bike at about 55 degrees of lean). From experience, this sensor doesn't always work haha. The 3-wire BAS has a ground wire, a redundant wire coming off of the stop/run circuit, and a wire that runs exclusively between the BAS and the ignition unit (this wire powers the magnets in the switch). Under normal operation, the wire between the ignition unit/BAS is grounded; if the bike tips, the sensor closes the ground and the stop/run circuit, effectively killing the bike.
Aftermarket ignition units (in my case, a Dynatek 2ki) don't have a wire out for the BAS, so the BAS will no longer function as a kill switch, and can be eliminated. No fancy wiring needed, just unplug the BAS or you could just leave the sensor there, it's no longer receiving power and can't function. If you really wanted to maintain the BAS with an aftermarket ignition unit, you could connect the wire that originally ran between BAS/ign to another closed constant 12V supply, and leave the stop/run and ground wires as-is.
If you're running a stock ignition unit and need to diagnose a faulty BAS, or eliminate the BAS (for whatever reason), you simply need to cap the stop/run circuit wire, and connect the wire that runs between BAS/ign to the ground.
Can't believe how much misinformation was out there. Wildest post was where someone confidently said the BAS acted as a "voltage stabilizer" for the stop/run circuit haha. Other than that being totally unnecessary and wrong, they hadn't even looked at the wiring diagrams to noticed that the stop/run wire on the BAS is an open circuit under normal operation haha. Can't regulate voltage on something that isn't connected when the bike is running.
Hopes this info helps someone who was getting as blatantly mislead like I was. Cheers.
*edit: Another common error I read, was people saying the BAS works with the turn signal module; this is untrue. The TSM and BAS are not connected in any way, BAS does not act as a turn signal canceller.
After doing lots of reading on forums about the BAS, I found a treasure trove of misleading info out there. Thought I would address what I found to be true in practice.
For those who don't know, carbed sporties have a sensor that detects harsh lean angles, and can shut the bike off if you drop it (sensor kills the bike at about 55 degrees of lean). From experience, this sensor doesn't always work haha. The 3-wire BAS has a ground wire, a redundant wire coming off of the stop/run circuit, and a wire that runs exclusively between the BAS and the ignition unit (this wire powers the magnets in the switch). Under normal operation, the wire between the ignition unit/BAS is grounded; if the bike tips, the sensor closes the ground and the stop/run circuit, effectively killing the bike.
Aftermarket ignition units (in my case, a Dynatek 2ki) don't have a wire out for the BAS, so the BAS will no longer function as a kill switch, and can be eliminated. No fancy wiring needed, just unplug the BAS or you could just leave the sensor there, it's no longer receiving power and can't function. If you really wanted to maintain the BAS with an aftermarket ignition unit, you could connect the wire that originally ran between BAS/ign to another closed constant 12V supply, and leave the stop/run and ground wires as-is.
If you're running a stock ignition unit and need to diagnose a faulty BAS, or eliminate the BAS (for whatever reason), you simply need to cap the stop/run circuit wire, and connect the wire that runs between BAS/ign to the ground.
Can't believe how much misinformation was out there. Wildest post was where someone confidently said the BAS acted as a "voltage stabilizer" for the stop/run circuit haha. Other than that being totally unnecessary and wrong, they hadn't even looked at the wiring diagrams to noticed that the stop/run wire on the BAS is an open circuit under normal operation haha. Can't regulate voltage on something that isn't connected when the bike is running.
Hopes this info helps someone who was getting as blatantly mislead like I was. Cheers.
*edit: Another common error I read, was people saying the BAS works with the turn signal module; this is untrue. The TSM and BAS are not connected in any way, BAS does not act as a turn signal canceller.
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