Total Motorcycle Bikers Dictionary
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One Percenter (1%er) – Worn by outlaw clubs. Made famous by the media that said 99% of bikers and clubs are law bidding citizens the other 1% is not. OFFO – South Florida Outlaws (1970’s)
| O.F.F.O. (OFFO) — Outlaws Forever, Forever Outlaws; Outlaw MC slogan. | |||
| Octane Rating — Measure of fuel’s resistance to engine knock. | |||
| Odometer — Device recording mileage, usually part of the speedometer. | |||
| OEM (Original Equipment Manufacturer) — Factory parts or the company that builds the bike. | |||
| Off‑Camber Turn — Corner banked higher on the inside than the outside. | |||
| Off‑Road Bike — Motorcycle designed for dirt, trails, or non‑paved terrain. | |||
| Off‑Road Helmet — Helmet with chin guard and sun shield, no visor. | |||
| O‑Gauge Wire — Heavy‑duty electrical wire used in custom wiring harnesses. | |||
| OHC (Overhead Cam) — Engine design with camshaft above the valves. | |||
| Öhlins — Swedish manufacturer of high‑performance suspension. | |||
| OHV (Overhead Valve) — Engine design with valves above the combustion chamber. | |||
| Oil Bag — Slang for oil tank. | |||
| Oil Bath — Lubrication system where parts are submerged in oil. | |||
| Oil Cooler — Radiator‑like device cooling engine oil. | |||
| Oil Dripper — Slang for older British/American bikes prone to leaks. | |||
| Oil Pressure Warning Light — Dashboard light indicating low oil pressure. | |||
| Oilhead — BMW air‑ and oil‑cooled Boxer engines. | |||
| Old Lady — Slang for wife or steady girlfriend of a club member. | |||
| O‑Level Service — Basic maintenance service level, often oil and filter changes. | |||
| On Rails — Expression for a bike cornering extremely well. | |||
| On the Box — Finishing in the top three, podium placement. | |||
| On the Gas — Slang for riding very fast. | |||
| On the Pipe — Two‑stroke engine running at peak RPM for max power. | |||
| One Percenter (1%er) — Outlaw club member patch, from AMA’s “99% law‑abiding” remark. | |||
| One‑Off — One‑of‑a‑kind custom part or motorcycle. | |||
| One‑Oh‑One — Slang for Indian Scout 101 model. | |||
| One‑Way SOB — Slang for a selfish rider who takes but doesn’t give. | |||
| Open Belt Drive — Exposed primary belt drive, common on custom choppers. | |||
| Open Circuit — Electrical circuit that is incomplete, preventing current flow. | |||
| Open Class — Sportbikes with engines over 800cc. | |||
| Open Class Racer — Competition motorcycle in the unlimited displacement category. | |||
| Open Cradle Frame — Frame without tubes under the engine; engine acts as stressed member. | |||
| Open Face Helmet — Helmet covering head but leaving face exposed. | |||
| Open Loop Fueling — Fuel injection mode without oxygen sensor feedback. | |||
| Open Pipes — Exhaust pipes without mufflers, very loud. | |||
| Open Primary — Exposed primary drive belt or chain on a custom bike. | |||
| Open Road — Slang for highway or long‑distance riding freedom. | |||
| Open Road Rally — Long‑distance group ride on highways. | |||
| Open Throttle — Riding with throttle fully engaged. | |||
| Open Track Day — Non‑competitive event where riders can practice on a racetrack. | |||
| Open Valve Timing — Engine valve timing when valves are fully open. | |||
| Open Wheel Bike — Motorcycle with exposed wheels, no fenders. | |||
| Operator Error — Mistake made by the rider, not the machine. | |||
| Operator Error — Rider mistake. | |||
| Operator’s License — Legal license to operate a motorcycle. | |||
| Operator’s Manual — Manufacturer’s instruction manual (synonym of Owner’s Manual). | |||
| OPG (Oil Pump Gear) — Oil pump drive gear, notably in Kawasaki Vulcans. | |||
| Optical Ignition — Ignition system triggered by light sensors. | |||
| Optical Ignition — Ignition triggered by light sensors. | |||
| Optimate — Brand of battery charger/maintainer. | |||
| Optimum Line — Best racing line through a corner. | |||
| Optimum Pressure — Correct tire pressure for performance and safety. | |||
| Optimum RPM — Engine speed where performance and efficiency peak. | |||
| Orange Book — Harley service manual. | |||
| Orange Book — Slang for Harley‑Davidson service manual. | |||
| Orange County Choppers (OCC) — Custom motorcycle builders, popularized on TV. | |||
| Orange Frame — KTM motorcycles, known for their orange frames. | |||
| Orange Paint Job — Custom orange paint scheme, often referencing Harley or KTM. | |||
| Organ Donor — Slang for a biker riding without a helmet. | |||
| Original Owner — First purchaser of a new motorcycle. | |||
| Originals — A member’s first set of club colors, never to be cleaned. | |||
| O‑Ring — Rubber sealing part, not always circular; used in engines and chains. | |||
| O‑Ring Chain — Motorcycle chain with O‑ring seals to retain lubrication. | |||
| O‑Ring Gasket — Rubber gasket used for sealing oil or coolant passages. | |||
| Ornamental Chrome — Decorative chrome parts with no functional purpose. | |||
| Orphan Bike — Rare motorcycle brand/model no longer in production. | |||
| Orphan Brand — Motorcycle brand no longer in production (e.g., BSA, Indian pre‑revival). | |||
| Orphan Parts — Hard‑to‑find parts for discontinued motorcycles. | |||
| Orphan Rider — Rider of a discontinued brand. | |||
| Orthodox Bars — Traditional handlebar style, not radically customized. | |||
| Orthodox Club — Traditional motorcycle club following AMA rules. | |||
| Oscar — Slang for an inattentive car driver (e.g., “Oscar almost turned left”). | |||
| O‑Spec — Manufacturer’s original specification for a motorcycle or part. | |||
| OTB (Over the Bars) — Crash where the rider goes over the handlebars. | |||
| Otto Cycle — Four‑stroke engine cycle, named after Nikolaus Otto. | |||
| O‑Tune — Slang for optimized tuning of an engine or ECU. | |||
| Out and Back Ride — Route that goes to a destination and returns the same way. | |||
| Out of Balance Wheel — Wheel not properly balanced, causing vibration. | |||
| Out of Gas — Running out of fuel mid‑ride. | |||
| Out of Round Tire — Tire worn unevenly, causing vibration. | |||
| Out of Spec — Component not meeting manufacturer specifications. | |||
| Out of Tune — Engine not running at peak performance. | |||
| Outback Ride — Long‑distance ride through remote terrain. | |||
| Outback Touring — Long‑distance motorcycle travel through remote or rugged terrain. | |||
| Outboard Brake — Brake mounted outside the wheel hub. | |||
| Outboard Motorbike — Slang for motorcycles with side‑mounted engines or accessories. | |||
| Outboard Pegs — Footpegs mounted wider than standard for stability. | |||
| Outboard Suspension — Suspension components mounted externally on custom builds. | |||
| Outlaw Biker — Member of a motorcycle club not sanctioned by the AMA. | |||
| Outlaw Club — MC not sanctioned by the AMA (e.g., Hells Angels, Outlaws). | |||
| Outlaw Colors — Club patches identifying outlaw motorcycle clubs. | |||
| Outlaw Rally — Rally dominated by outlaw motorcycle clubs. | |||
| Outlaw Rider — Member of an outlaw motorcycle club. | |||
| Outlaw Run — Group ride organized by outlaw clubs. | |||
| Outlaw Spirit — Cultural ethos of independence and rebellion in biker culture. | |||
| Outrider — Rider who scouts ahead or rides at the edge of a group for safety. | |||
| Outrigger — Stabilizing wheel or float attached to a motorcycle, often for training or sidecar rigs. | |||
| Outrigger Wheel — Training wheel for beginner or disabled riders. | |||
| Outside Apex — Racing term for the outermost point of a corner. | |||
| Outside Line — Racing term for taking the outer path through a corner. | |||
| Over and Under Exhaust — Exhaust system with pipes stacked vertically. | |||
| Overbalance — Rider tipping past recovery point, often at low speed. | |||
| Overbalanced — When a rider tips past the point of recovery, often at low speed. | |||
| Overbore — Enlarging cylinder bore to increase displacement. | |||
| Overbore Cylinder — Cylinder enlarged beyond stock bore size. | |||
| Overbore Kit — Cylinder modification kit that increases displacement. | |||
| Overbraked Front — Excessive front brake use causing the wheel to lock. | |||
| Overbraked Rear — Excessive rear brake use causing a skid. | |||
| Overbraking — Applying too much brake, causing loss of traction. | |||
| Overbraking Zone — Area on track where riders often brake too hard. | |||
| Overbuilt Frame — Frame designed stronger than necessary, often heavier. | |||
| Overclutching — Overuse of the clutch, leading to wear or overheating. | |||
| Overcompensate — Rider reaction that is too strong, often worsening control. | |||
| Overcooked Corner — Entering a corner too fast to hold the line. | |||
| Overdamped Forks — Forks with too much damping, reducing responsiveness. | |||
| Overdamped Suspension — Suspension with too much damping, reducing responsiveness. | |||
| Overdrive — Transmission gear ratio less than 1:1, reducing engine RPM. | |||
| Overdrive Gear — Transmission gear ratio less than 1:1, lowering RPM at speed. | |||
| Overexposed Rider — Rider lacking protective gear, vulnerable to injury. | |||
| Overfilled Oil — Too much oil in the crankcase, causing foaming or leaks. | |||
| Overfilled Tank — Fuel tank filled beyond safe level. | |||
| Overgeared — Bike geared too tall, reducing acceleration. | |||
| Overgeared Setup — Gearing too tall for conditions, reducing acceleration. | |||
| Overgrip — Excessive grip on handlebars, leading to fatigue. | |||
| Overhead Cam (OHC) — Camshaft located above the valves. | |||
| Overhead Cam System — Camshaft directly actuating valves. | |||
| Overhead Valve (OHV) — Engine design with pushrods operating valves. | |||
| Overheated Brakes — Brakes losing effectiveness due to heat buildup. | |||
| Overheated Engine — Engine running above safe temperature. | |||
| Overland Ride — Long‑distance motorcycle journey across countries or continents. | |||
| Overlean — Excessive lean angle, risking traction loss. | |||
| Overloaded Bike — Motorcycle carrying more weight than recommended. | |||
| Overloaded Suspension — Suspension compressed beyond its design limits. | |||
| Overnight Rally — Rally event lasting through the night. | |||
| Overpack — Carrying excessive luggage on a motorcycle. | |||
| Overpolished Chrome — Chrome worn thin from excessive polishing. | |||
| Overpowered Bike — Motorcycle with more power than a rider can safely handle. | |||
| Overpriced Accessory — Aftermarket part considered too costly for its value. | |||
| Overpriced Accessory — Aftermarket part considered too costly. | |||
| Overrev — Running an engine beyond its redline. | |||
| Overrev Limiter — Electronic system preventing engine overrev. | |||
| Overridden ABS — Anti‑lock braking system disabled or bypassed. | |||
| Overridden Aero Limit — Rider exceeding aerodynamic allocation. | |||
| Overridden Appeal — Rider ignoring appeal. | |||
| Overridden Authority — Rider ignoring authority. | |||
| Overridden Ban — Rider ignoring ban. | |||
| Overridden Black Flag — Rider ignoring black flag disqualification. | |||
| Overridden Blue Flag — Rider ignoring blue flag (being lapped). | |||
| Overridden Certification — Bike no longer meeting certification standards. | |||
| Overridden Championship Limit — Rider exceeding championship allocation. | |||
| Overridden Chance — Rider ignoring chance. | |||
| Overridden Chassis Limit — Rider exceeding chassis allocation. | |||
| Overridden Checkered Flag — Rider ignoring race finish. | |||
| Overridden Code — Rider ignoring code. | |||
| Overridden Common Sense — Rider ignoring common sense. | |||
| Overridden Compliance — Bike no longer compliant with regulations. | |||
| Overridden Court — Rider ignoring court. | |||
| Overridden Death — Rider ignoring death. | |||
| Overridden Destiny — Rider ignoring destiny. | |||
| Overridden ECU — ECU tuned beyond safe factory limits. | |||
| Overridden Electronics — Rider ignoring electronics. | |||
| Overridden Emissions — Emissions controls bypassed or disabled. | |||
| Overridden Engine Limit — Rider exceeding engine allocation. | |||
| Overridden Engineering — Rider ignoring engineering. | |||
| Overridden Ethics — Rider ignoring ethics. | |||
| Overridden Exhaust — Exhaust system modified beyond legal or safe limits. | |||
| Overridden Fate — Rider ignoring fate. | |||
| Overridden Federation — Rider ignoring federation rules. | |||
| Overridden Fine — Rider ignoring fine. | |||
| Overridden Flag Rule — Rider ignoring racing flag rules. | |||
| Overridden Fuel Limit — Rider exceeding fuel limit. | |||
| Overridden Fuel Map — ECU fuel map altered beyond safe limits. | |||
| Overridden Gearbox Limit — Rider exceeding gearbox allocation. | |||
| Overridden God — Rider ignoring God. | |||
| Overridden Government — Rider ignoring government. | |||
| Overridden Gravity — Rider ignoring gravity. | |||
| Overridden Green Flag — Rider ignoring green flag start. | |||
| Overridden Hardware — Rider ignoring hardware. | |||
| Overridden Homologation — Race bike modified beyond homologation rules. | |||
| Overridden Ignition — Ignition system modified beyond factory limits. | |||
| Overridden Inspection — Bike failing inspection due to modifications. | |||
| Overridden Insurance — Insurance voided by illegal modifications. | |||
| Overridden Law — Rider ignoring law. | |||
| Overridden Life — Rider ignoring life. | |||
| Overridden Lighting — Lighting modified beyond legal standards. | |||
| Overridden Logic — Rider ignoring logic. | |||
| Overridden Luck — Rider ignoring luck. | |||
| Overridden Marshal — Rider ignoring marshal instructions. | |||
| Overridden Mathematics — Rider ignoring mathematics. | |||
| Overridden Mechanics — Rider ignoring mechanics. | |||
| Overridden Morals — Rider ignoring morals. | |||
| Overridden Noise Limit — Exhaust noise exceeding legal limits. | |||
| Overridden Pace Car — Rider ignoring pace car rules. | |||
| Overridden Penalty — Rider ignoring or bypassing penalties. | |||
| Overridden Physics — Rider ignoring physics. | |||
| Overridden Pit Board — Rider ignoring pit board instructions. | |||
| Overridden Pit Speed — Rider exceeding pit lane speed limit. | |||
| Overridden Plate Mount — License plate mounted illegally. | |||
| Overridden Police — Rider ignoring police. | |||
| Overridden Practice Limit — Rider exceeding practice allocation. | |||
| Overridden Probability — Rider ignoring probability. | |||
| Overridden Protest — Rider ignoring protest. | |||
| Overridden Qualifying Limit — Rider exceeding qualifying allocation. | |||
| Overridden Race Control — Rider ignoring race control orders. | |||
| Overridden Race Limit — Rider exceeding race allocation. | |||
| Overridden Reality — Rider ignoring reality. | |||
| Overridden Reason — Rider ignoring reason. | |||
| Overridden Red Flag — Rider ignoring red flag stoppage. | |||
| Overridden Registration — Registration invalid due to modifications. | |||
| Overridden Regulation — Rider ignoring regulation. | |||
| Overridden Rev Limiter — Rev limiter bypassed for higher RPM. | |||
| Overridden Rider — Rider going beyond their skill level. | |||
| Overridden Rider Aid — General term for disabled electronic rider aids. | |||
| Overridden Rulebook — Rider ignoring rulebook. | |||
| Overridden Safety — Rider ignoring safety. | |||
| Overridden Safety — Safety systems bypassed or disabled. | |||
| Overridden Safety Car — Rider ignoring safety car rules. | |||
| Overridden Sanction — Rider ignoring sanction. | |||
| Overridden Sanity — Rider ignoring sanity. | |||
| Overridden Science — Rider ignoring science. | |||
| Overridden Season Limit — Rider exceeding season allocation. | |||
| Overridden Software — Rider ignoring software. | |||
| Overridden Speed Limiter — Speed limiter bypassed for higher top speed. | |||
| Overridden Stability Control — Stability system disabled or bypassed. | |||
| Overridden Standard — Rider ignoring standard. | |||
| Overridden Statistics — Rider ignoring statistics. | |||
| Overridden Steward — Rider ignoring steward instructions. | |||
| Overridden Strategy — Rider ignoring race strategy. | |||
| Overridden Suspension — Suspension settings unsuitable for conditions. | |||
| Overridden System — Rider ignoring system. | |||
| Overridden Team Order — Rider ignoring team orders. | |||
| Overridden Technology — Rider ignoring technology. | |||
| Overridden Testing Limit — Rider exceeding testing allocation. | |||
| Overridden Tire — Tire pushed beyond its grip limits. | |||
| Overridden Tire Limit — Rider exceeding tire allocation. | |||
| Overridden Track Limit — Rider exceeding track limits. | |||
| Overridden Traction Control — Traction control disabled or bypassed. | |||
| Overridden Tribunal — Rider ignoring tribunal. | |||
| Overridden Universe — Rider ignoring universe. | |||
| Overridden Warranty — Warranty voided by excessive modifications. | |||
| Overridden White Flag — Rider ignoring last‑lap flag. | |||
| Overridden Yellow Flag — Rider ignoring caution flag. | |||
| Overrun — Engine braking effect when throttle is closed at high RPM. | |||
| Overshoot — Running wide out of a corner due to excess speed. | |||
| Oversprung Suspension — Suspension with springs too stiff for the rider. | |||
| Oversquare Engine — Bore larger than stroke, allowing higher RPM. | |||
| Oversteer — Rear tire skids before the front in cornering. | |||
| Overstressed Frame — Frame subjected to loads beyond design. | |||
| Overtake — Passing another vehicle. | |||
| Overtake Lane — Lane designated for passing. | |||
| Overtake Rule — Racing rule governing passing. | |||
| Overtake Signal — Hand or light signal for passing. | |||
| Overtightened Bolt — Bolt damaged by excessive torque. | |||
| Overtired — Rider fatigue leading to reduced focus. | |||
| Overtorque — Applying too much torque to a fastener. | |||
| Overtravel — Suspension movement beyond intended range. | |||
| Overtravel Suspension — Suspension movement beyond its intended range, risking damage. | |||
| Overtuned Engine — Engine tuned beyond safe reliability. | |||
| Overvoltage — Electrical surge exceeding the system’s design, potentially damaging components. | |||
| Overweight Bike — Motorcycle considered heavy for its class. | |||
| Overweight Rider — Rider heavier than the suspension rating, requiring adjustments or upgrades. | |||
| Overweight Touring Bike — Touring motorcycle considered heavy for its class, affecting handling. | |||
| O‑Wheel — Slang for a wheelie, lifting the front wheel under power. | |||
| O‑Wheel — Slang for a wheelie. | |||
| Owl Run — Informal slang for a late‑night group ride. | |||
| Owl Run — Slang for a late‑night group ride. | |||
| Owner’s Group (H.O.G.) — Harley Owners Group, a global riding community sponsored by Harley‑Davidson. | |||
| Owner’s Manual — Manufacturer’s instruction manual. | |||
| Owner’s Patch — Patch signifying original ownership of a motorcycle or club membership. | |||
| Owner’s Pride — Slang for a rider’s first or most cherished motorcycle. | |||
| Oxidation — Corrosion of metal parts, often from exposure to air and moisture. | |||
| Oxidizing Catalytic Converter — Converts CO and HC into CO₂ and H₂O. | |||
| Oxy‑Acetylene Torch — Tool used in custom fabrication and repairs, especially for frames and exhausts. | |||
| Oxy‑Acetylene Torch — Tool used in custom fabrication and repairs. | |||
| O‑Z Racing — Italian manufacturer of high‑performance motorcycle wheels. | |||
| O‑Z Spec — Racing wheel specification. | |||
| O‑Z Track — Slang for racing on O‑Z wheels. | |||
| O‑Z Wheel — Racing wheel produced by O‑Z, known for lightweight strength. | |||
| O‑Zone — Slang for a rider’s personal comfort or performance zone. | |||
| Ozone Cracking — Rubber deterioration caused by ozone exposure, common in tires. | |||
| Ozone Layer Ride — Slang for high‑altitude mountain rides. | |||

