Ignorance has never kept me from having an opinion, so following are a few suggestions untainted by any clue whatever about your project. I limited this to shorter works, on the theory that they'd be easier bricks from which to assemble your whatever it is. Oh, and they're also mostly pretty old, like me.
Sartori in Tangier - King Crimson, from Beat - 3:36 - quiet 45 sec intro to get the gear on, then I can see the bike action begin
No Love Lost - Joy Division, from An Ideal for Living - 3:40; vocals come in at 1:59, but oh, that intro! Maybe too noisy for what you want, though.
Loomer - My Bloody Valentine, from Loveless - 2:38; not technically an instrumental, but the vocals (as well as the instruments) are so distorted it might as well be. Yeah, I have the new "followup" m b v that just came out these mere 21 years later, but I still gotta go with a cut from Loveless http://www.youtube.com/watch?v=ztnutktJP7M
Any Colour You Like - Pink Floyd, from Dark Side of the Moon - 3:26 Maybe too recognizable if you're looking for obscure, but who knows, it might be just the ticket. http://www.youtube.com/watch?v=NbKAh3zJmH8
Vonal Declosion - Stereolab, from Margerine Eclipse - Not an instrumental, but the vocals are in French, so same difference
West of Bald Knob - Marshall Crenshaw, from 447 - 3:27 - Way laid back, if that's what you need
not on Youtube! Marshall just does not get the attention he deserves.
Judy is a Dick Slap - Belle & Sebastian, from Push, Barman... - 4:06 - I can easily conjure video in my head for this one
Gravelrash - Midnight Oil, from Breather - 3:28 - laid back, but with drive Perfect for a video - some video, somewhere.
pH Factor - The dB's, from Repercussion - 2:30 - in a similar vein as Gravelrash The video link is a live performance; the album cut would likely better suit
A Fifth of Beethoven - Walter Murphy & the Big Apple Band - 3:01 - Is it disco time again, yet? I lived through it once.,,