You did not buy a unit recommended for bike use. The 2620 uses a hard drive. The vibrations from the bike are doing a number on it and it will likely cause it to fail completely real soon if you continue to use it on the bike. If you want a bike GPS, and like the 2620 form factor, then I would recommend that you sell the 2620 on eBay, and get either a 2610, 2720, 2730, 2820, or one of the new Zumos. They are all flash based and Garmin recommended them for bikes. The 2610, 2720, and 2730 have all been discontinued, so you can get refurbs at a great price. 27XX will have better screens, and 2730 supports XM. I have a 2730 and love it.
Red 2006 V-Strom 650: "the most shockingly competent machine in the world today"
Alpenkönig (a.k.a. King of the Alps): 2005, 2006
1989 Sportster Bobber Hardtail
1990 Electra Glide with Cop Bags