Re: Speedo for my 26" Bike
I and many others have had very good luck with the $10.00 Schwinn 12 function wired speedometer from, 'shudder', Wally World. I currently have three that perform perfectly if, as Mapbike said, you keep the wire away from the CDI and any cable that is directly attached to the engine. One of mine has accurately accrued over 1000 miles without resetting itself or giving false info.
There is a trick to making it work right: There is a hard to see arrow on the pick-up that attaches to the front fork. The magnet that goes on the spokes must perfectly align with that arrow or you'll get erratic readings.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"