LiftMaster Soldering, Mo-Door Purchase, IP67 Momentary Switch, Flash2Pass
Just to add some data points, my experience in this area, some of which may be relevant here, give folks some ideas, etc.
1) On a Victory bagger, I added some wires and did some soldering on a spare LiftMaster remote, added a momentary switch, drilled a hole, and installed the finished product under the fairing. I have a gallery of this process -- pics, links, captions -- on my web site, here, which shows the solder points, among other things.
2) On my next attempt on another bike, I used a second spare transmitter, but butchered the soldering (and hence the circuit board). Like
@Grouchy (see earlier post), I don't have very much experience with tiny soldering. So, I said screw it, and bought a Mo-Door opener:
We make garage door opener remotes for motorcycles! No more fumbling with bulky openers or typing numbers into key pads! Simply just pull in!
www.mo-door.com
I installed this up-front, under the nose-cone tupperware, on a 650 Burgman. I did make a minor mod: I didn't like the thin switch that came with the Mo-Door, so I snipped it off, and replaced that with a Urtone UR162 (which I discovered after I used a switch from Eastern Beaver on the Victory/LiftMaster setup):
Momentary Push Button Switch, URTONE UR162, 1NO SPST DC 30V AC 220V 3A Aluminum Alloy Metal Shell Suitable for 16mm 5/8" Mounting Hole – Black: Amazon.com: Industrial & Scientific
www.amazon.com
I put the switch on the dash area of the Big Burger (upper left in this pic, for left-hand use):
This setup works fine, with the caveat that the inner push-button area has become sort of a bronze color; this doesn't bother me, given that the switch has worked flawlessly, but it might concern some. I haven't had to replace the battery in four or five years now. Incidentally, I have a HomeLink-equipped car, and the Mo-Door has a greater range than the car; I can easily press this a house or two away, coming up the street before turning into my driveway.
3) There is a device, similar to what
@shooks wants to accomplish (see earlier post), called Flash2Pass:
Buy the Flash 2 Pass 103102 Garage Door Opener Complete Set for Motorcycles at North Shore Commercial Door, starting from just $89.95. We offer excellent customer service, fast shipping, and great selection. Can't find what you're looking for? Call us!
www.northshorecommercialdoor.com
Currently unavailable on Amazon:
Buy Flash2Pass 204102 Garage Door/Gate Opener for Motorcycles: Tools & Home Improvement - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
www.amazon.com
I recall reading about this for a decade or so, but have no experience with it.
4) I must admit that talking to a smart device is an interesting concept, one I hadn't thought about before. My wife and I have an Alexa device, and one outlet controlled by it.
There's even this all-purpose smart-home device -- and probably others -- available (and, again, no experience with it):
meross Smart Garage Door Opener Remote, Compatible with Apple HomeKit, Amazon Alexa, Google Assistant, SmartThings, Multiple Notification Modes, No Hub Needed - - Amazon.com
www.amazon.com
OTOH, it sure is easy to lift a hand off the left grip and press a button for a less than a second, i.e., the way I have my current Burgman set up ... and not have to worry about having a mic on a helmet, or a phone, and so forth. I do check my pre-ride pressures with a phone with the FOBO app, so I'm not a total Luddite, but I am very pleased with the Mo-Door and UR162, FWIW.