I know cops is the pat on the head(helmet), that I pay attention to. What are the others?
slow down / danger ahead / possible cop = arm out, palm down, pressing downward like you're patting on the head.
hazard = point to it with leg on that side. Alternative: sometimes I give a quick slow down sign and then stand up on the pegs a bit so the people behind me know that there's a road hazard that might bottom out their suspension.
cop (alternative and less used) = circle with one finger up like you're mimicking a siren
need gas = exaggerated pointing at the fuel tank
pull over = left arm up and over head pointing to the right (unless you live in one of those places where they drive on the wrong side of the road)
blinker is on = close fist, open hand with fingers spread wide, close fist, open hand, close fist (like a blinker)
blinker (alternative) = make an L with your finger and thumb. Close it so acts like Pacman. Repeat again and again like it's a blinker.
pass me = left arm down, palm facing forward, wave the people behind you to come forward
left turn = left arm out
right turn = left arm up at 90 degrees
stop = technically it's left arm down at 90 degrees. I use the "slow down" signal.
follow me = pat your cowl or passenger seat. Often done right after you pass someone. You can turn around, look at them or point to them and then pat the cowl.
Look over there = point your visor like you're trying to poke yourself in the eyes with two splayed fingers (ala 3 stooges). Then point to what you want someone to look at.
wheelie = left arm out with palm down. Lift whole left forearm and hand about 45 degrees while keeping your elbow in the same place. Then set it back down.
"you ok?" = point and give them the ok sign.
You/he/she is a squid = hand out, palm down, fingers apart and hanging like squid tenticles, move the fingers around a bit
hang up the phone = make an exxagerated hang loose sign with your pinky and thumb (like it's a phone), hold it up high and bring it down, pretending like it's a phone that you're hanging up. Alternative: hold the hang loose sign to your helmet like you're talking on the phone and then hang it up. Helps if you point.
Get off my ass (to a tailgating cager) = turn around and hold your arm out with your hand at 90 degrees and your palm facing hte tailgater. Push it toward them, as if to tell them to back up. Then hold up a hand to say thank you.
Need to stop for bathroom -- point at your junk. Alternative: point at your junk and use your left hand to sign a hose that is on and uncontrollably whipping around
Whew! Close one = wipe brow
Wanna race? = point to someone, point to yourself, go into an exxagerated tuck,
Kiss my ass = stand up in the seat and smack your ass
We're going too slow (frustrated) = foot off the pegs, pretend like you are pushing the bike along. Alternative: make pedalling motions.
WTF are you doing? = both arms up as if to say WTF? Also works for "where the make the beast with two backs is this guy going" or, if done less affirmatively, "I'm lost" or "I don't know"
I'm faster than you (mocking) = pass someone and make exaggerated rowing motions like it's a canoe.
That bike is hawt = make throttle signs with your hand, point to bike, then hump your tank
That chick is hot = hump the tank
You are hot = stand up on the pegs and hump the air.
You are hot and I want to get nasty with you = stand up on the pegs, hump the air, then smack the air in front of you like it's an ass.
You are hot and I want you to get nasty with me = stand up on the pegs, hump the air, then smack your own ass.
I'm an idiot = point to yourself then pretend to shoot yourself in the head
He's an idiot = pretend to shoot him.