How to Install a DENALI SoundBomb Original Air Horn On A ‘21 BMW R1250GSA

December 30 2021

How to Install a DENALI SoundBomb Original Air Horn On A ‘21 BMW R1250GSA

It seems only natural to install the DENALI SoundBomb on the BMW R1250GSA adventure motorcycle- both are tough, loud, and ready for adventure. Walk through the process of installing the DENALI SoundBomb on the BMW R1250GSA including the tools needed, additional parts needed, and tips and tricks to make your install go smoothly!

Installation Time: 30-60 minutes

Tools Required:

  • 13mm Socket or Wrench (to tighten 
  • T-40 Torx Bit (to remove OEM Fairing stay bolt for mount)
  • M5 allen bit (to tighten Horn Mount to bike)

Product(s) Required:

Additional Products Available:

Pre-Installation notes/Advice:

  • Keep the compressor within 25 degrees of vertical. DO NOT mount sideways, it must be mounted vertical to to ensure many years of function
  • The BMW Adapter is only needed when you want to replace the OEM horn. It is NOT required when the CANsmart is used for installation. It is also NOT required when you do not want to replace the OEM horn when installing the Horn Harness available separately. 
  • Confirm polarity on the horn, or the horn will spin backwards and will sound like a drunk duck. Funny, but NOT effective!
  • Connect to the battery after all other connections are completed
  • The SoundBomb can cause discoloration on the brake line, without the protective wrap installed (included with the horn mount). Use it!
  • Place a stocking over the trumpets if you’re putting the bike in storage/going info hardcore offroad or muddy conditions. Any debris in the trumpet opening can cause issues to both function and product longevity!
  • Make sure part numbers match what you ordered
  • Loose fit all components first before tightening down
  • Channel any wiring along frame/existing harness paths and under fuel tank
  • As always, turn the handlebars fully left, fully right, and fully compress the suspension. Confirm that the lights do not interfere with operation and that the wires have enough slack to account for all suspension and steering movement. 

Installation Instructions:

1) Remove the LOWER OEM Fairing bolt with a Torx T-40 bit. It helps to turn the handlebars to create more room. Access from under the fairing is easier rather than going from above. (Photo shown below is taken from the front tire, looking up under the bike).

2) Install the bracket to the horn. Ensure the short arm (40mm) of the mount is mounted to the horn, and the longer arm (45mm) is mounted to the bike. A 13mm socket or wrench is required and keep it loose! You want wiggle room to ensure there are no fitment issues with the forks and the bars at full lock.

2.1) Place the head of the bolt included with the Horn inside the metal channel of the SoundBomb. It helps to put the SoundBomb upside down so gravity can help keep it in the channel. When tightening, make sure the head of the bolt is flush and fully seated. I would recommend tightening this nut fully at this stage. It will be very difficult to do when mounted to the bike. Just ensure the mount is parallel to the direction of the compressor and not crooked. This will help center it when installed on the bike. 

2.2) Now would be a good time to install the included protective wrap around the brake line. The SoundBomb can rub against the brake lines and cause discoloration. You may have to slide or relocate the retainers for the brake line.

3) Mount the horn to the bike. Start the long M8x60 ISO 7380 bolt included with the mount by hand. Don’t forget medium strength thread-locker! It is a long screw and will take awhile.  Press the mount as far back towards the direction of the seat that it can go. It’s OK at this time to tighten this bolt snug, to keep it from moving. Use an M5 Allen/Hex Bit. 

4) Press the horn as far back towards the direction of the seat that it can go. Do your best to center the horn between the forks. This should ideally give you the best clearance from the fork movement. Move the bars full lock, left to right while watching if the forks hit the horn. Hold the front brake and compress the front suspension. Once you're happy with the fitment, torque the mount bolt to 18 Nm (13.5 ft-lbs). 

5) Continue with wiring. Connect the wiring to the terminals and run the wires along the frame, taking care to avoid any hot, or moving parts. Zip ties are your friend! Make sure you get the polarity correct. When installed, the negative spade connector is closest to you, while the positive is furthest. 


As always, should you have any questions about this install or installing DENALI Electronics to your motorcycle, please contact us! Our Customer Service Team is here to help make you safer on and off the road.

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