there was an entire thread about this on a riding forum that i read every once and a while, so i compiled the best ones to bring here.

let me see, bikes are better than women because:

1.       You can turn them on whenever you want to
2.       You can turn them off whenever you want to
3.       You can ride them as hard as you like
4.       They don't have a mother in law
5.       They take YOU to dinner
6.       You can trade them in
7.       They don't get upset when you're riding newer models
8.       You like the way they sound, even when they're loud
9.       Mine's naked all the time
10.     Parts are easier to replace
11.     They come with an Owner's Manual
12.     They don’t mind when you sit on them and fart
13.     When their wheels rust you can get new ones
14.     When they get really old they are more valuable than ever
15.     When their battery is dead you can jump start them
16.     They never hesitate when you want to strip them down
17.     Their seat stays the same size for their entire existence
18.     You can own more than one
19.     You can ride whichever one you want, when you want, without the others pitching a fit
20.     They don't mind sleeping in the garage
21.     You can swap motorcycles with a friend and they won't get upset
22.     You can bring a black bike home to the meet the folks
23.     A kick-start won't land you in jail with a restraining order
24.     You'll actually miss your old bike when you move on to the next
25.     Once you’re done with your old bike you actually get a chance to get some money for it and will never have to pay for a ride you no longer have again
26.     If your bike doesn't meet your exact specs you can modify it until it does
27.     Flushing fluids should be based on mileage, not time
28.     If the bike leaves you stranded, you can at least get her towed to a shop
29.     Will not take your clothes
30.     Does not bleed and bloat
31.     They are cheaper to refuel
32.     Our friends actually like your new bike and every bike before and after that
33.     They don't care about anniversaries
34.     They don't need space
35.     They take YOU on vacations
36.     They won't move into your apartment
37.     They won't take your credit cards and charge up a storm
38.     They won't complain if you strip her naked, spend hours on end hammering, burning, electrocuting, and twisting on her, and won’t even want to cuddle afterwards
39.     Will wait patiently for you while you attend to your needs with the hottie you just met
40.     Will not call you a typical male
41.     A bike will never ask you if its butt looks fat in those jeans
42.     You can always ride it, and it doesn't have to be in the "mood" for riding
43.     And unless you sell 'em...she'll always, ALWAYS be there for you

feel free to add your own....