Everyone hates spam (except for the 17 people making money filling my email box)... that is a given... so if you are going to do something with a flyer... give something away. A coupon for a water bottle for instance or a flat kit or something. This has the effect of first having people retain the flyer, and second, they come to the store for the item.

To attach a flyer to a bike, use rubber bands. Just one simple band will hold paper to handlebar.

Good luck, but again, everyone hates spam... keep that in mind.