BakUp backrest and motor adjustment for it

After I had made the rider's seat power height adjuster I got the idea of the backrest adjuster from Bruce Hodges (aka "bruce2000ltc") on the BMWLT.com back in 2008. He was using one of the battery operated screwdrivers to do the adjusting and while searching the right kind of unit I probably mentioned about this on the forum. The next surprise came in mailbox as some weeks later I received a small power screwdriver from Anthony Kay (aka "deputy 5211") who even refused to receive a payment for the unit!
OK, thanks to the help from my American LT colleagues I now had both the idea and components in my hands, time to get things done...

This hint came from Bruce. The original spring that pushes the backrest forward is too strong for the motor adjuster. So it needed to be trimmed to make it weaker.

Here is the actual motor. As it was taken out from it's original housing it was no longer held together by it so I needed some epoxy glue to keep it together. Looks like I also needed to trim the cover a little bit.

Here is the BakUp frame and I used some fiberglass putty to make the new housing for the motor. I applied soft putty in the frame and then pressed the motor in place to make the shape. Motor was covered with Ceran wrap I borrowed from my wife's kitchen so the putty would not stick to it. The allen screw has a piece of a cut allen wrench in it which in turn is the standard size the power screwdrivers use.

Here the motor is in place and it is covered with some shrink tube for moisture protection. The idea is that the motor turns the adjuster screw which determines the angle of the backrest. The piece of allen wrench connecting motor and bolt must be long enough to allow the screw travel up and down since the motor does not move. 

A small challenge was the voltage of the motor, 3,6 V. So I used the battery case and added an old Nokia car charger for charging the batteries. 

For those I found space in the bikes's main electrical box under the gas tank. 

To run the motor in two directions via two push buttons I needed two relays to change the directions. The relays operate with 12 V, and the low voltage is run through the relay pins. The next picture shows the schematics but the text is in Fnnish, sorry...OOPS, now I realized that at some point I had replaced the battery pack with a simple USB 5 V charger. The motor is run only for a max 2 seconds so it can easily tolerate the 1,4 volts overvoltage.  

To adjust the backrest I use the horizontal buttons of the old four way radio band selector. (The vertical buttons are for the seat up/down.) This is and old picture as the upper button set is nowadays on the left handlebar....

Like ths...

Here is the motor hidden under a little larger vinyl cover than the original. 

This adjuster has worked since 2008. I oil the adjuster screw every now and then. That is all it has needed so far.