Pre-load & RAP Adjusters

Pre-load & RAP adjusters

One of the benefits of the RoadWing is that you can adjust the pre-load without having to jack up the bike and wrench on the shock. The pre-load can be adjusted with an electric Remote Adjustable Pre-load (RAP adjuster) or a manual RAP adjuster. The electric RAP adjuster is part of the set-up on the Honda Gold Wing. Most times the electric RAP adjuster comes with the shock.

The RAP adjuster can stiffen or soften the ride. It does lift the bike a little, but that is not the main purpose of it. Ideally, adding a RoadWing increases the weight capacity, improves handling and eliminates the bottoming out issue with the original Road Star suspension.

Electric RAP adjuster

In order to use the electric RAP you will need to create or purchase a harness.

There are two types of harnesses that you can use.

1.  Double Pole Double Throw switch (DPDT). I have begun creating this type of harness. It is much cheaper and less complicated to create.

The DPDT harness is a momentary switch and is plug and play for the Honda GL1800 actuator (RAP motor). It is constructed with all new material. In addition to the 8″ of wire from the switch, I add 6″ of wire to the side that connects to the motor. As seen in the picture I use the OEM Sumitomo socket so that it is plug and play with the RAP motor. In addition to the 8″ of wire from the switch, I use 12″ of wire to the side that connects to the battery. The positive side has an inline fuse. I solder the wires and use heat shrink to protect them. I also use wire loom to cover the wires. I use 16g wire and a 10a fuse. In the event you need to replace the fuse only use 10a. The switch includes a mount for under the seat.. It will easily mount to the right side fender bolt. Pictures are provided below. I set it up so that when you pull up on the switch it increases pre-load and down reduces it.

DPDT Electric RAP Harness

This is a wiring diagram for the DPDT harness.

Please Note: How to increase the pre-load: with the writing on the side of the switch facing you, press the switch to the right. To decrease pre-load press it to the left. Do not decrease the electric RAP all the way out. This may cause it to hang up. If this happens you can fix it. Check out the FAQ for instructions on how to fix it.

Do not decrease the electric RAP all the way out. This may cause it to hang up. If this happens you can fix it. Check out the RoadWing FAQ page for instructions on how to fix it.

2. The original harness is made by Chris Jones (the creator of the RoadWing) and uses relays. You can read about it at his website.

Credit: Chris Jones

Below is an image created by Chris Jones with the set-up of the harness that he created and offers for sale. You can build your own, if desired.

Credit: Chris Jones

What RAP adjuster is best for me?

This will depend on which Road Star you have. Either RAP will work  on any year Road Star. The key issue involves where to locate the electric RAP. Location will differ between the 99-07 (carburetor) and 08-14 (fuel injected) models. I have an 04 but if I had an 08-14, I would go with the manual RAP.

The 99-07 models allow for the electric RAP to be stored under the right side cover. This is not the case with the 08-14 models.

Details & suggestions for a mount location of the electric RAP for both models is found on the install instructions page.

Housing the electric RAP adjuster

1999-2007 Models

2008-2014 Models


Manual RAP adjuster

Since the the manual RAP adjustercomes from a different motorcycle they are extra. The following RAP adjusters will work to adjust the pre-load on the RoadWing. Most often the RAP adjuster will come with a shock. Pull the RAP adjuster and hose and scrap the shock.

  • Suzuki Burgman AN400
  • 03-09 Honda 1300
  • BMW rear mono shock on a 650, 1100, 1150 or 1200
  • Kawasaki Concours
  • Kawasaki ZZR1200
  • Kawasaki Ninja ZX1000
  • Buell XB12

The Burgman RAP adjuster requires modification. I put together an instructional video below.

Sometimes the guys that convert them have them or you can search for one on eBay. Suggested mounting locations for the manual RAP can be found on below and on the install instructions page.


Kris Koehler makes and sells a this one. It is made from part of the electric RAP adjuster.

Credit Kris Koehler

Mounting the manual RAP adjuster

Bleed and install your RAP adjuster


Suzuki Burgman RAP adjuster modification