R (Motorcycle designation suffix) – Replica, Racer or Racing (eg. Yamaha YZF600R, BMW K1200R)
RR (Motorcycle designation suffix) – Race Replica or Race Ready (eg. Honda CBR600RR, Kawasaki ZX-10RR)
Race can – A lightweight, free breathing muffler.
Racer – A person licensed to race.
Racing Flags – Racing flags are traditionally used in auto racing and similar motorsports to communicate important messages to drivers by a flagman. While there is no universal system of racing flags across all of motorsports, most series have standardized them, with some flags carrying over between series.
Black Flag – Rider disqualified or problem with motorcycle
Checkered Flag – First across wins: race over
Green Flag – Race start signal
Red Flag – Race stopped
White Flag – One lap left to race
Yellow Flag – Caution, do not pass if flag is waving
Yellow and Red Striped Flag – Caution, indicates debris, fluid or hazard
Radial – 1. Tire design where the cords of the tire run from the left side of the tire to the right side. 2. Refers to the way the cords of a tire on constructed. 3. The tire construction utilizing plies that run radially from bead to bead under the tread. This construction requires a belt to stabilize the tread and define the tire diameter.
Radiator – In liquid-cooled engines, the heat sink where excess heat is purged into the environment. An external heat sink that dissipates the heat in the liquid that ran through the engine and to return it back into the engine cooler than it was before it exited then engine and entered the radiator.
Rainbows – Oil on the street
Rainbows in the Mountains – When angry locals in the mountains put diesel fuel in the corners in an effort to stop sports bikes street fighting.
Rain Grooves – Channels cut into a roads surface to help water run off the road during a rainstorm.
Raised Tranny – Harley bikers would use a spacer to raise the transmission on their bikes so when riding in dirt and mud to try to keep the primary cover away from anything that might knock into it.
Rake – 1. Rake, measured in degrees, describes the angle of the front fork or the steering axis from the horizontal or vertical plane. 2. Slope of the front forks.
Rat Bike – Bike made from several machines and kept on the road using as cheap as possible and painted matt black. Now has a class of its own and defined as any thing Mad Max would shoot at.
Rat Bike (#2) – A cosmetically challenged bike. It can be anything from a ‘no maintenance’ bike to a fine running ‘sleeper’.
Rat Bike (#3) – The bike you use in foul weather or when you are going into a questionable neighborhood. A cheap reliable bike, but if lost or stolen is no big deal. This bike never gets washed.
Reading the plugs – A close examination of the spark plugs to determine the mixture of fuel/air (too lean, to rich, etc)
Rear end – The rear wheel and swingarm of a motorcycle.
Rear sets – Foot controls that have been relocated at the rear of the motorcycle.
Rebound – Rebound defines the return stroke of the suspension.
Reciprocating Weight – Total weight of all moving parts.
Rectifier – A component that converts alternating current into direct current.
Red Line (Redline) – Indicates the maximum RPM’s an engine may run. The name is derived from the actual red line manufacturers typically put on the tachometer.
Reduced effect – In some countries certain motorcycle models are sold with less horse power to comply with legal or insurance regulations in that country. For instance, a country might allow 16-year-olds to drive 125 ccm bikes with no more than 15 hp. The bike would then have to be modified to output no more than 15 hp. In another example insurance companies may not want to insure bikes with more than 100 hp, or may increase insurance rates for these bikes to the extent that most people would want to buy a reduced-effect version of their bike instead.
Relay – A light current electrical switch that triggers a heavier switch capable of caring heavier current.
Renthal – A manufacturer of after-market parts, most notable for handlebars and sprockets. ‘Renthals’ typically refers to the type of high, flat bars that are frequently fitted to Streetfighters.
Repair Link – A link in some motorcycle chains that can be disassembled for chain repair.
Repli-racers – Hard edged sportbikes. These motorcycles are characterized by riding positions that tuck the rider into an extreme crouch, forcing him or her to practically lay down on the fuel tank.
Repo – Repossess. To take away from an owner who cannot financially afford to pay for an item they own.
Repo Artist – Business thug experienced at repossessing motorcycles for finance companies.
Retard – To set back the ignition timing before the piston reaches TDC (Top Dead Center.)
Rev(s) – See Revolutions Per Minute (RPM). A term used to describe how fast a motor is spinning.
Revving – The action of using the throttle in quick short burts to speed up the engine.
Revolutions per minute – RPM – REV – 1. The number of times the crankshaft spins around each minute. 2. The number of revolutions the engine makes in a minute. Abbreviated RPM and often referred to as “rev” in conversation.
Revolutions per mile – The measured number of revolutions made by a tire traveling one mile.
Revolution® – The Revolution® engine, Harley-Davidson’s first water-cooled engine (V-Twin, produced from 2002 – Current Day)
Rice Burner – Slang for Japanese-made motorcycle.
Rice Grinder – Slang for Japanese-made motorcycles.
Rice Rocket – Japanese Sport Bike
Rich – condition where the optimum mixture of fuel and air is not being fed to the engine, too much fuel, not enough air; opposite of lean
Rich mixture / Rich burn – A fuel-air mixture that has a relatively high proportion of fuel and a relatively low proportion of air.
Ride Captain – The leader of a group Ride.
Ride Lieutenant – The last (and most experienced) rider in a group ride.
Riding Two Up – Carrying a passenger on your bike.
Rigid or Rigid Frame – A type of frame that has no swingarm, it is a one piece neck to rear axle frame.
Rippin’ it Up – (1):When a biker pulls away hard and fast from a standstill and leaves behind a patch/line of rubber (2): A term used to describe generally fast, skillful and/or aggressive riding.
Risers – See also Handlebar Risers – Designed to correct the ergonomic short comings of your motorcycle, handlebar risers will raise your handlebars vertically to allow you to attain the posture needed for maximum control. Risers can simply extend the bar mounts toward you, or extend up and forward. Risers are designed to be mounted between your stock bar mount and triple clamp.
Road Agent – Another term for Highway Patrol Officer or State Trooper.
Road Crown – Arc of road, high at the middle line, to allow for water drainage.
Road Gator – 18-wheel Tire Pieces
Road Rash – 1. A Wipeout that scrapes off some of your skin. Marks left behind on a biker’s body after falling down while moving. 2. A term used to define injuries to the skin when a rider falls or is thrown from the motorcycle and lands or slides on the pavement. Wearing a full-face helmet, gloves, a motorcycle approved jacket, chaps, and boots is a good way to minimize Road Rash.
Roadie – Yamaha Road Star
Rocker – Part of M/C Colors usually designating geographic location. The curved patches of a club’s patch, typically denotes the club name or chapter on one and resident town or city on the other.
Rocker Arms – Devices that work like upside down teeter totters and push on the valve stems.
Rocker-Clutch or Rocker Clutch Pedal – This term was used to describe the foot clutch pedal’s that rocked back and forth on a central pivot point hence the term Rocker-Clutch) and the rider would step on the front toe section to disengage the clutch and the rear section with the heal of your boot to engage the clutch.
Rodger Flannel – Boring. Dull.
Rolling Basket – Basket case bike, fairly intact but does not run, needs work
Rolling Chassis – 1. Incomplete project, has everything but mill & tranny (engine and transmission.). 2. The assembled frame, wheels and suspension of the bike.
Rolling on the Throttle– Giving the bike more power by giving it more gas to accelerate.
Rollover – The condition that occurs during hard cornering when a tire sidewall rubs the road surface.
Roost – 1. The spray of dirt off the rear wheel of a motocross motorcycle. 2. The expression used when the spray off the rear tire lands on to another rider and embarassing them.
Rossi – Valentino Rossi. Vale. The Doctor. Valentinik. Rossifumi. Possibly the greatest motorcycle racer of all time. See also Rossi Wannabe.
Rossi Wannabe – An obsessive male rider with the mistaken belief that looking like a clone of Rossi will somehow mysteriously gift them the same level of riding skill. Traditionally found clad head-to-toe in black and yellow Dainese clothing and riding a Babyblade in Nastro Azzuro colours.
Roun To-It – Instrument used to delay a job. ie… one of these days i’ll get around to it.
RPM – Revolutions Per Minute. Example is in reference to how fast the pistons in an engine are moving.
RUB – Rich Urban Biker. A term usually used by real Harley Bikers to describe the weekend wannabe accountant types who buy a Harley ”cause they can and the status of it, but couldn’t tell a camshaft from a brake pad. Bikers that ride with more money than knowledge, experience, and “”street saavy””.
Rubber – Tires, tyres.
Rubber band effect – Whenever a group of two or more motorcycles ride together on the road there is a time lag between when the first bike in the group changes speed and when the following bikes do the same. This is known as the ‘rubber-band effect’.
Rubber Mounted – Rubber mounted engines use a system of rubber cusions and/or joined engine mounts to isolate engine vibrations from the rider.
Rubberside – Towards the bottom of the bike, or bottom area of a part or component
Run – Riding for a particular function or purpose
Runout – The measure of the out of roundness of the tire causing a vibration that cannot be balanced.
Ruts – When the terrain is soft or damp, deep channels or ruts can be formed when the rear tires dig through the dirt. Ruts can force riders to take certain lines through a corner, or limit them to only one line, making passing difficult. Ruts can get deep enough to completely stop a motorcycle.