Dave wrote on 05/23/12 at 11:26:01:


I'm pretty sure the VaporTech reads your speed using a sensor and magnet just like the bicycle computers.  So your gearing or sprockets would have no bearing on it reading your speed.

KiranOtter wrote on 05/24/12 at 11:00:48:


Dave is correct.  It reads a magnet/sensor combo on the front (or rear) wheel.  What you set is the circumference of the wheel.

I use a VaporTech on one of my bikes.

KiranOtter wrote on 05/24/12 at 11:00:48:


Well......the stock speedometer that is cable driven does read incorrectly when you change the gearing using sprockets.  My point was that the Vaportech was a way to get an accurate speedometer reading if you did change sprockets.....or tire sizes.

As long as I'm riding continuously I can remember my last fillup odo reading and just wait until I accumulate 125 miles or so.   However, when the bike is parked for several days I need a reminder of when I filled up last, especially since I live in a remote area where nearest town is 30 miles away.   Here is the solution I came up with.   You can slide plastic tubing on the hasp to keep it from scratching and hang around the handlebars, mirror, etc.   These are $2.80 on eBay including ship.

I bought a Sigma BC509 as the BC800 was not available.  It was the lowest cost and has the basic functions (speed, trip meter, and clock).  I installed the sensor as pictured and calibrated the wheel circumference but simply rolling the bike along the driveway.  One mark where the valve stem is at the bottom of the wheel rotation then the next mark after one full rotation.  For my 2006 LS650 the circumference is 2032 mm.  
I found one problem.  The length of wire between the sensor and the computer was too short to reach the handlebars.  I tried attaching the computer to the left front turn signal which worked well.  Then I decided I really wanted in on the handlebars so I spliced in about 12 inches of additional wire.  Not a big problem except that the sensor wire is very fine and hard to work with.
Once I got the sensor and computer where I wanted them, I attached four of the Radio Shack rare earth magnets.  Everything works great!!  I also found that the in tank mechanical speedometer is very accurate.  The digital and mechanical speedometers agreed within 1 mph over a range from 5-65 mph.  
This is a great mod!  Thanks to everyone who did the background work!

Dont know if this would pertain to this topic, but I use an app on my iphone everytime I fill up. It records the date, miles, mpg, and price per gallon, if I want to know when to filll up I just look on the app quickly

(Can't figure out how to add more than one attachment yet in YaBB)