I picked this up at Wally World for 20 bones, I didn't even realize till I got home that it was wireless. I haven't really missed my speedo since liberating it from the bike, but I have missed having an odometer to monitor fuel usage.

The first obstacle I encountered was how/where to mount the magnet pick-up? As you probably already know, the mounting method is engineered for spoke installation only. I rolled the bike into the middle of the garage and stared at it for a good 30 minutes. Several ideas came to mind, but none seemed worth the effort, or would be too permanent to the wheel.
Then it dawned on me, mount it to the valve stem. A piece of scrap metal, and a little time with the vise, hammer, band saw, drill and a drop of 15 min epoxy to keep it threaded in...this is what I came up with. Not too happy with the spike valve stem cap, but it allows me to get it very hand tight. The sending unit was easy, I zip tied it to the lower fork slider like you would on a bicycle.

It has large numbers and is easy to read at speed. It's not very hard core choppa' but it works, was very cheap, and it's not permanent.

It also has a back lit function, it doesn't stay on but if I really need to see it at night I can tap the button...oh, and as an added bonus, I can monitor how many calories I'm burning while riding. Hahahahaha!