Major additions by Kurt (Major Softie) and James (Silicone
dictionary of motorcycle terms is mostly specific to BMW and/or related to motorcycling in general. The list will never be finished or completely
accurate. Each word or term can have volumes written about it.
Send me your suggestions and I will save them. When I have several, I
will use them as I see fit. Many of the definitions have links to
something directly related. To learn more about many of these terms,
just use Google. Here is an
American to British dictionary. Jeff Dean
has a great page for
English to German
and one for
German to English The vocabulary is just for motorcycle terms.
What do the three letters BMW stand
Second Rule; Keep two seconds between motorcycles when riding in formation.
2-Stroke; A two stroke engine is one with two strokes, or movements up or
down, per cycle.
4-Stroke; A four stroke engine is one with four strokes, or movements up or
down, per cycle.
Related to getting the maximum spark with a magneto ignition system.
Also called the E-gap.
ABS Motorcycle Brakes; The same as a car, Anti-lock
Braking System http://motorcycles.about.com/cs/beginners/g/def114.htm
Aftermarket; An accessory, or part, made for your motorcycle
by someone other than the original manufacturer.
Air/fuel ratio; The mixture of fuel and air produced
by carburetion or fuel injection. A comparison between the amount of air and
amount of fuel going into the combustion chamber.
Airhead; A BMW that is mostly cooled by air and not by water or oil. The
name of a major BMW club.
Allen key, or wrench; A type of hexagonal
Altitudinal changes; This refers to the change in combustion mixture
when changing altitude. More of an issue with the older bikes using slide
Amps; Short for ampere, the term for the flow of electrical current.
Anti-seize compound; A somewhat greasy paste that is added to threads
to keep them from sticking. The best example on a BMW is the exhaust threads
on the head. One of
Really high handlebars, mostly on choppers, but I have seen them on a BMW. http://motorcycles.about.com/cs/beginners/g/def060.htm
ATE; The huge
world wide company that made the first disc brake for BMW in 1974 with the /6
series. They were well known for not working well. In fact, the
single disc did not work nearly as well as the former drum brake of the /5
babbit; The bearing compound found in plain crankshaft bearings.
back roads; Off the main highway, often preferred by motorcyclists.
A head and neck "sock" with mouth and eye slits. http://motorcycles.about.com/cs/beginners/g/def003.htm
balancing carbs; The procedure for getting two or more carbs tuned
properly to allow smooth running of the engine.
Barn queen; A motorcycle that has been stored in a barn or other
outbuilding for many years.
Basket case; A motorcycle that has been taken apart. For the
person who still expects to put it back together, it is a project, but the
buyer calls it a basket case. http://motorcycles.about.com/cs/beginners/g/def062.htm
Bearing has flat spots; See "bearings are notched" below
Bearing preload; The slight pressure holding tapered bearings together.
Commonly used on BMW.
Bearing race; One of the two bearing surfaces that balls or rollers
Bearing spun; A bearing can spin in the case that is supposed to hold
it. This may damage the case, or aluminum hub.
Bearings are notched; Ball or roller bearings can get worn spots on
them that are felt easily. Those are flat spots.
Beemer; a slang term
for a BMW motorcycle. Often confused with Bimmer, the car
Bench seat; or banana seat; A long seat for two people.
Big Ends; The larger ends of the connecting rods which attach to
the crankshaft of the engine.
Biker; An "image" of a person who rides a motorcycle,
often limited to those fitting the outlaw image.
Bikini fairing; A very short and small fairing, more for style than
Bill Mayer; Known for making large comfortable seats for motorcycles,
A slang term for a BMW car.
Bottom end; The crankshaft,
crankshaft bearings, journals, webs and connecting rod lower ends of an
engine. An engine is considered to have a top end and a bottom end.
Bowman; A manufacturer of aftermarket oil pans and other engine
accessories for BMW motorcycles in the late 60s.
Boxer; A slang term for an horizontally
opposed engine where each piston has its own crank pin.
The term comes from the image of the two pistons traveling towards each other
and looking like boxers fighting.
Brain; The small computer which controls fuel, engine, and ABS brake
functions on BMW's after 1984.
Brake pads vs. shoes; A disc brake uses pads for the friction material
and a drum brake uses shoes.
Brake squeal; A loud squeal coming from the brake.
Certain models are more prone to this malady.
Brembo: BMW began using the
Brembo brakes in 1981 (I think) and they worked far better than the former
brakes by ATE.
Brick; Referring to the water cooled inline BMW motorcycle engines
that came out in 84. Also slang for a very
hard stock seat.
Brights; The high beam of the
Brushes; The carbon electrical parts that rub against the commutator
Buffeted, buffeting; Referring to the wind experienced while riding a motorcycle,
often coming around a fairing.
Bump start; A way to start a motorcycle by turning on the ignition, placing it in gear, disengaging the clutch, then
running along side the motorcycle, jumping on and engaging the clutch
suddenly. Hard on the drive train and clutch but will start a bike with a dead
battery when no one is around to provide a "jump".
Bun burner; A long and grueling ride
which makes the posterior sore.
A stretch cord for attaching things to a motorcycle. http://motorcycles.about.com/cs/beginners/g/def065.htm
Burning rubber; Starting out quickly and spinning the rear wheel.
Burning up miles; Just going down the highway.
Bushing; Usually a bronze part to act as a bearing.
Butter head; Term coined by Duane Ausherman to describe the heads on
certain years of /2 BMW motorcycle where the
alloy of the heads is too soft.
Cables, or Bowden
cable; The mechanical cables that operate the clutch, fuel and brakes
of a motorcycle.
Cafe Racer; A light weight fast motorcycle designed for style or
going fast in curvy areas http://motorcycles.about.com/cs/beginners/g/def140.htm
Carb; Short for carburetor, the part that mixed fuel and air on older
Center of gravity, or just cg; That point on the
motorcycle where there is equal weight all around. A balance point.
Center stand; The mechanical stand that holds the motorcycle vertically
Chair; A common term for a side car.
Chilton manual; One of the common workshop manuals for BMW motorcycles
and other vehicles. It was probably the worst of the manuals.
Choke; A device to assist starting a cold engine by making the
fuel/air mixture "richer" in fuel.
choke/enrichment circuit; The part of a carb used for cold starting
circlip; A type of fastener that looked like the letter "C"
It snapped into a groove, on a shaft, to retain something. Sometimes
called a C clip.
Classic; A period of time for a class of car or motorcycle for showing.
Clear title; Having a legal title of ownership to a vehicle.
Clip-ons; A type of handlebar that is very low for road racing.
Concours; Short for the
French term "Concours d' Elegance" and it is a car show. Also
used to refer to a standard of excellence of condition for vehicles as in,
that old BMW is restored to Concours.
cone; The inner part of a tapered roller bearing.
Corbin; A manufacturer of aftermarket
saddles for BMWs. Provided OEM custom seats for BMW for a few years in the
late 80s and early 90s.
Corrosion; Oxidation or rust on a part.
Cotter pin; a part that goes through a hole in a shaft and is then bent
over. It will keep the nut from backing off.
Counter steering; A highly controversial term relating to the
steering of a motorcycle http://motorcycles.about.com/cs/beginners/g/def008.htm
Crank it over. To turn an engine over in the process of starting it
Crankcase breather; The term for the part of system of exhausting the
gasses out of the crankcase or lower end of an engine.
Crankshaft; The main shaft of an
engine to which the piston connecting rods attach.
Craven; A British manufacturer of aftermarket luggage for BMWs.
Cross winds; Wind flow at an angle
to the direction of travel of the motorcycle.
Crotch Rocket; http://motorcycles.about.com/cs/beginners/g/def046.htm
Cruisers. A style of large motorcycle.
crush-washer, A copper washer used on a drain plug to
"crush" as it is tightened to ensure a good seal. On
this page you can see an example of a used (crushed) and new (uncrushed)
CS; The suffix of a few models of BMW for sport.
scalloping; The natural wear on a motorcycle tire that is
mistakenly thought by some to indicate a problem.
CV, or constant vacuum carb; In 1970 BMW began using
a CV carb on the R75/5. The older type was called a slide carburetor.
Dampener; Commonly a hydraulic
piston or friction assembly used to lessen vibration or oscillation.
Day-Long; A type of custom motorcycle seat made by Bill Russell often
found on BMWs. http://www.day-long.com/new_pages/prices.html
Dealer; A seller of motorcycles authorized by the factory, or importer.
Deep oil pan; A type of oil pan that either increases the supply of
oil or increases its cooling, or both. See
Detonation; The firing of the mixture in the combustion chamber before
it should. Not a good thing See
Pinging and pre-ignition.
Diaphragms; The round rubber "skin" found in a CV carb. They first came out on BMW in 1970. It also applies
to the flat clutch spring used on the /2 and later.
Ding; A nick or scratch in the paint.
diode board; An electrical device that allows current to flow in one
direction only. Usually as part of the diode board and the rectifier of the
Dip stick; The long slender piece of metal that goes into the oil
collection point of an engine, or sump, to check the oil level.
Disc (Brit) = rotor (Yank)
DOHC; Acronym of Double Over Head Camshaft.
DOT Helmet Rating; An acronym of Department Of Transportation.
A motorcycle safety helmet standard. http://motorcycles.about.com/cs/beginners/g/def059.htm
Double-leading shoe brake; Relating to a type of drum brake with both shoes
having leading edges during braking. Used by BMW from mid 50s-late 70s
on the front wheel.
Dresser; A motorcycle
"dressed" with many accessories - luggage, fairing, trunk,
Dropped valve; The head of the valve broke off and is in the
combustion chamber. Usually great damage occurs.
Dry Clutch; A type of clutch system usually found on cars, but is
normal for BMW motorcycles
Dual plugging; Adding a second
spark plug to the head of a BMW motorcycle. It was/is popular on the /5
motorcycles due partly to poor fuel and/or wanting more power.
Dual shock; Relating to the older models that had a shock absorber on
each side of the BMW. In 1981 BMW came out with the first single shock
dwell; Relating to the amount of time that points are closed in the
older battery coil ignition system. Don't waste your time measuring it,
as it is Not needed for BMW.
An E shaped clip fastener. Used in a few places on a BMW motorcycle.
E-gap; Also called Abrisz, see above.
Earles; The name of the man who invented the leading link forks used
on BMW motorcycles from late 55 through 1969. Especially good for
earth (Brit) = ground (Yank) Referring to electricity.
easy/eze/ezy-clutch; An invention to give the clutch lever more leverage
and allow easy pull of the clutch hand lever.
EFI; Electronic Fuel Injection.
Used on BMWs with the introduction of the K models in 1984.
Engine casing; The external case
that encloses all the parts of an engine.
Everbest; A type of fuel petcock used on BMWs
from 1955 until 1974.
EZ Berg; A manufacturer of custom saddles for BMW motorcycles in the
F; The prefix for a line of 650 cc single motorcycles
with a chain drive. The
Chain Gang club.
FAG; A major company that makes bearings found in BMW motorcycles.
Fairings; A protective covering over the front and sometimes sides of
a motorcycle to make it either more aerodynamic or protect the rider from wind
and rain, or both.
They are typically one of two types. The best and safest is the frame
mounted fairing. More prone to wobbles are the handle bar mounted
fairings or windshields.
False neutral; When one shifts gears and finds neutral
is a sign of poor technique or a technical problem.
Fan blade; The blades of the fan
behind the radiator of a water cooled K bike.
Fan Shroud; The cooling which encloses the fan on a K bike.
Faulty ground; A poor ground (earth) connection
Feathering the brake; Gently applying the brake
feathering the clutch; Gently allowing the clutch to engage.
This makes for a slow smooth start.
Final drive; The last item in a BMW motorcycle drive train where the
energy gets turned 90 degrees to the wheel. Often mislabeled (due to
similarities to a car)
differential, or rear end. It is known to "gain oil"
and have the wheel drive splines wear.
Flat spot; As the
throttle opens up to increase rpm, sometimes one will find a place just off
idle where the engine seems to hesitate. That is a flat spot.
floating disc; On a disc brake the actual disc may "float"
and not be fixed.
Float bowl; a chamber that holds a specific amount of fuel and keeps it
constant. In it is usually some type of float. The
"bowl" may be removable for easy cleaning.
Foot pegs; The resting place for ones feet on a motorcycle. The
passenger foot pegs often will fold up and out of the way.
Foot pounds; A term for describing how much to tighten or move
something. So many pounds of pull on a lever of so many feet.
Fork rake; The angle between the vertical
and the fork legs.
Forks; The mechanism on the front of a motorcycle that holds the
wheel, allows steering, and provides shock absorption.
Frankenbike; A motorcycle made up of many. Since BMW would keep
many interchangeable parts for years, it is common for
people to assemble a
BMW out of parts of many years.
fuel tap (Brit) = petcock (Yank)
Gas cap; The cover for the fuel inlet on a tank.
Gasket; A paper, rubber or cork part that goes between two metal parts
to become a seal.
Gasoline foot; The result of fuel dripping onto ones foot. Not
unknown on a BMW to have a float stick or leak and allow some leakage.
Gearbox (Brit) = transmission, tranny, box (Yank)
Gear lash; The play between two gears.
Gear whine; The noise made by gears that aren't spaced correctly or
Gremlin; A gremlin is blamed when one can't find the defect or cause
of some malady.
Ground; The return path of an electrical circuit, "Earth"
in Brit speak.
Grounding the plugs; During certain ignition tests, one must remove
and lay a plug against the engine. This is to observe the existence of a
G/S; The acronym for Gelande Strasse
GS; The acronym for Gelande Sport, or terrain (land) machine.
gudgeon pin (Brit) = wrist pin (Yank) That is the pin
where the piston pivots on the rod.
H4; A quartz halogen bulb used commonly in a BMW headlight.
Introduced in 1974 on the /6 models, it was the first motorcycle in the USA to
have the approval for street use.
All about bulbs.
sidehack; A common slang term for a sidecar.
Hall-effect; A type of ignition system introduced on BMW in 1980.
Info for the ever curious.
Halogen; The type of headlight bulb used since 1974 by BMW contains
inert gas. Will be damaged if the glass is touched with your finger.
hand painted stripes; The typical pin stripes found on a BMW
motorcycle that were hand painted by women at the assembly plant.
Handgrip; The rubber grip on the handlebars to make a more comfortable
Handlebar fairing; A type of wind screen that is mounted directly to the
forks. Not recommended on a older BMW.
Big fairing test.
Haynes manual; One of the main four workshop manuals for BMW.
Headlight bucket, or shell; The enclosure that holds the headlamp, usually
Head; The portion of the engine that sits atop the cylinder. It
is the part that holds the spark plug.
Heated handgrips; Electric hand grips can be fitted to help keep hands
warm in really cold weather.
Heavy floats; Carbs have floats to regulate the fuel level. They
can become soaked with gas and sink. That is a heavy float.
Heinrich; Manufacturer of aftermarket
accessories for BMWs, notably fuel tanks and fairings.
High speed wobble; An oscillation of the forks at a high speed.
It is extremely dangerous and often results in a crash.
High side; A crash where the motorcycle slides out and rather
than just skid to a stop, it flips and the rider and bike start tumbling.
Far more dangerous than low siding. http://motorcycles.about.com/cs/beginners/g/def070.htm
Highway pegs; Extended foot pegs which
allow the rider to stretch out the legs once under way.
Hit the pavement; An idiom for crashing a motorcycle.
Hit the road; Get on the bike and start riding.
hone; A special type stone to treat the sides of a cylinder.
Horsepower; A measure of the power put out by an engine http://motorcycles.about.com/cs/beginners/g/def125.htm
Hoske; Ernst Hoske was the manufacturer of aftermarket
accessories for older BMW motorcycles, notably fuel tanks, and mufflers.
Hydroplaning; When riding in rain at too fast of a speed, the tire can
skip over the top of the water and lose traction. The same as in a car,
but less likely on a motorcycle
Hylomar; The brand name of a type of non hardening gasket sealer.
Many favor it for use in certain applications on a BMW. BMW has
authorized its use.
IBMWR; An Internet
national BMW riders organization. Highly recommended.
Idle mixture; The fuel/air mixture at a low rpm called idle. See
"flat spot" above.
Idle stops; The mechanical part of the carb that keeps the idle up
high enough so that the engine doesn't quit. On a BMW motorcycle it is
Ignition leads; The special wire that connects the ignition coil to the
spark plug. Also called high tension lead.
inline; Usually describing the type of engine layout. The K100
and K75 are examples of the inline engine. The opposed (boxer) is not.
Intermittent shorts; About the worst type of electrical problem to
have, as it is usually hard to diagnose. See "short" below.
butt; A very long hard ride.
JB weld; A commonly used epoxy glue that is so good it can be
Jesus clip; This is the "E" clip that holds the handlebar switches
together. It is very hard to install this tiny part.
The name comes from the phrase that is commonly uttered when it flies away and gets
lost and then the person says, "Oh Jesus."
jet needle; This is a carb part that meters the fuel going through a
jet, or hole.
jet; A carb part that has a very precise hole to restrict fuel flow
Jugs; On a BMW, the cylinders are commonly called jugs. Shame on
you for thinking that.
Real jugs are
on the left side.
Jump starting; When the battery is too low to start the engine, one
can jump start it from a good battery. It takes a pair of large size
electric cables and some knowledge to do so safely.
K; The prefix of several models of BMW.
K&N; An aftermarket company that manufactures air filters.
They are washable and reusable. While that seems to be economical, some
argue that they don't filter as well and shorten the life of the top end of
Kicking Tires; Slang term for standing
around motorcycles and talking about them.
Kick start; Before motorcycles had electric starters, they all used
kick starters. A lever that one would kick to turn the engine.
Knock; Just as in cars, it usually refers to a noise made by a loose
rod. Not a nice noise to find. It usually means expensive lower
knurl; An often misunderstood process applied to a piston to make the
Kompressor; German for supercharger.
A few high performance BMW twins were known as "Kompressors" in 1939.
Krauser; Manufacturer of aftermarket
removable luggage for BMWs in the
1970s and 1980s
Lash; A term for play or looseness, often related to the
Lean; 1. A carb mixture that doesn't have enough fuel in it. 2.
To go around a curve, the motorcycle must lean.
Leaning into cross winds; As a cross wind hits a motorcycle, it
naturally leans into the wind to stay about in the same track.
Leather; This usually is used when referring to riding clothing.
Lid; Safety helmet.
Light the fire; Slang term for
"start the engine".
Linkage; A mechanical connection between two things. For
example; the parts that link the foot shift lever to the inside parts of the
Loctite; The brand name of a very common glue to hold something in
place. First used on motorcycles to keep nuts and bolts together.
It is made in many varieties for various uses.
longitudinal; A directional term meaning
along the center line of the motorcycle from back to front. BMW flat twins
crankshaft and drive shaft aligned in a "longitudinal" direction.
lower end; An engine is usually considered in two parts, the top end and
bottom or lower end. The lower end is the crankshaft and related parts.
Lowers; The portion of a fairing that protects the legs and is commonly
removable for summer weather.
Low side; Where the motorcycle slides out sideways with the
wheels going down the road first
LT; A suffix on some BMW motorcycle models, usually large touring
bikes. Some claim it means light truck.
lube (Brit) = grease (Yank)
Luftmeister; A manufacturer of
accessories and fairings for BMW motorcycles. Well known to be
Luggage; The storage space for clothing and other things in a touring
motorcycle, usually removable.
LWB; Acronym for Long Wheel Base.
Magneto; self powered ignition generator. Commonly used on BMW until
MC; Acronym for Motorcycle.
Main Bearing; A large bearing which
supports a portion of the crankshaft.
Main Bearing Journal; The part of the engine case where the Main Bearing
Metric Cruiser; http://motorcycles.about.com/cs/beginners/g/def160.htm
MSF; acronym for the Motorcycle Safety Foundation. A group
dedicated to safety through well planned motorcycle riding lessons. http://motorcycles.about.com/cs/beginners/g/def022.htm
Naked Bike; The basic model of a motorcycle without fairing or
Naval Jelly; A liquid that removes rust in preparation for paint.
needle bearing; A type of frictionless bearing that is actually a very
NIB, The acronym for New In Box.
NOS; An acronym for New Old Stock. While the part was manufactured
many years ago, it is new, original and not a reproduction part.
Nyloc; A type of nut for a bolt that has a plastic insert to keep it
from backing off from vibration. It replaces the lock washer.
O Ring; A rubber sealing part.
OEM; An acronym for Original Equipment Manufacturer. The BMW factory
only assembles parts that are purchased from sub contractors. Those
companies are OEM. BMW puts these parts in their own packaging.
The part may be available from the
OEM also, but in different packaging.
Off road; Riding that is not on a legal road. Usually used for
OHC; Acronym for Over Head Camshaft. Having the cam over head
means that it is located above the head, rather than in the lower end.
It reduces the reciprocating mass and allows higher rpm.
Ohms law; The electrical term for resistance. It is named after
OHV; Acronym for Over Head Valve. This arrangement allows for
better fuel flow into the combustion chamber. That means more power.
Oil pan; A BMW engine has a wet sump. That means that the oil is
in the bottom of the engine. A cover is bolted on the bottom of the
engine and it is the oil pan. It is possible for the oil pan to leak a
bit of oil.
Original owner; This would be the first owner of the motorcycle
purchased from the dealer.
Out-tracking; The process of breaking
the straight ahead wheel alignment of a motorcycle in order to turn. See
oversquare; If the diameter of a piston is larger than the stroke, it
is considered to be "oversquare" This allows higher rpm and
Owners manual; The book supplied with a new BMW motorcycle. It
has riding information, warranty and minor service work explained. Some
BMW manuals are available online, such as the /2
pannier; Brit speak for
Patches; The cloth "patches" are sewed onto a jacket or
shirt to signify a club, brand or something of note.
Perch wedge; The small part of older BMW motorcycle handle bar
controls to keep them from rotating on the handle bars.
Petcock; The valve that turns off the fuel to the engine.
See some general examples.
Petrol (Brit) = gasoline, or just gas (Yank) = Benzine (central Europe)
rear seat or rider on a motorcycle
pinstripe; The hand painted lines that so distinguish a BMW.
Pinging; Pinking in Brit speak. It is the ignition of fuel too
early in the combustion chamber. It sounds like a tinkle or minor
rattle. It is not good for the piston. See detonation above.
Piston slap; The noise a cold piston makes as it hits the cylinder
sides. It is usually because the piston skirt is too small for the
cylinder. Often it goes away when the piston expands due to heat.
In severe cases, it never stops making the slap.
Play; The "looseness" of parts.
Plugs fouled; If the fuel isn't fully burned during combustion, then
it is common for the unburned carbon to deposit on the spark plugs. This can
short out the ignition spark and stop the firing of the cylinder. The
plug must be cleaned and the reason for it to foul found out before all things are right.
Plugs too cold; A cold plug doesn't
have a hot enough spark to burn off carbon deposits and will foul (see above)
Plugs too hot; A hot plug produces a
spark so hot that it will fire the air/fuel mixture before the valves are shut
and the piston is in the proper position for the down stroke. The result is pre-detonation
or pinging which can hole the piston. http://www.dansmc.com/sparkplugs1.htm
plunger-frame; In 1937 BMW came out with a rear sprung wheel. It
had no dampening, but at least it would move up and down to stay with the
uneven road surface somewhat.
PO; Acronym for Previous Owner. This is the unknown person on
which to blame all defects of a used BMW.
Points; The switch of the older style ignition system called
"battery coil" or Kettering.
Poker Run; A common social activity of motorcycle groups.
The group rides to different check points and each rider "draws"
another card. At the end, the one holding the best poker hand wins
some prize. http://motorcycles.about.com/cs/beginners/g/def064.htm
pop the bead, or break the bead; This relates to fixing a flat or
changing a tire. It is pushing the edge of the tire off of the edge of
Pot; cylinder, with or without head. A Brit term
Rubber Cow; Comes indeed from the German "Gummikuh" (which
sounds a lot better pronounced goo-mi-kooh, but with slightly shorter oo's). It wasn't given to our bikes as a reference to their
extreme comfort, or to describe an oscillation on long sweepers. The term "Kuh" was bestowed upon our bikes by a famous German
motorcycle journalist somewhere in the third quarter of the previous century, who had immediately noticed the pinion drive effect and
commented that the bike behaved like a cow. Cows, as some of you may well know, raise their hindquarters first when they decide to stand up
and go for a walk, exactly like our bikes do when you open the throttle.
The same effect makes the rear end squat when you close the throttle.
And when you do that in a turn, the bike suddenly feels as if it's made from
rubber or is hinged in the middle. It may have to do with frame stiffness.
Hence the term "rubber cow".
Popping the clutch; Letting the clutch out quickly to make a fast
Porous wheels; a cast
wheel made for tubeless tires that has a defect where the air leaks out.
The ignition of the compressed fuel ahead of time. See detonation.
Pre-load shifter lever; A trick in helping the BMW shift smoothly and
quietly, with less of a clunk.
Progressive spring; The name of a company that makes front fork
springs for BMW
PSI; Acronym for Pounds per Square Inch.
Purring; Referring to a smooth running engine.
quad-leading shoe; A drum brake with 4 leading shoes, not ever
supplied on a BMW
R; The Prefix for all years of BMW up to 1984. It is short for Rad, the German term for wheel.
race; Could mean a race for speed, or a part of a bearing.
Rake and Trail; http://motorcycles.about.com/cs/beginners/g/def025.htm
Rally; A group meeting of like minded individuals, usually on a weekend
and commonly at a camping place.
Rat Bike; A really tattered motorcycle, sometimes befitting a BMW that
is just used for transportation. http://motorcycles.about.com/cs/beginners/g/def049.htm
Reading plugs; A close examination of the spark plugs to
determine the mixture of fuel/air.
Rear main seal; The seal at the rear of the crankshaft to keep the oil
in the engine and the air out.
Rear sets; Foot controls that have been relocated at the rear of the
rebound damping; Related to damping of a shock absorber during the
extending portion of the cycle. It would restrict the spring somewhat.
Renovation; A bike that is renewed mechanically/cosmetically and hopefully in
good taste. Often improved over original and frequently called a
restoration, but that is an error.
Resistance; An electrical term and measured in Ohms. See Ohms law
Resister caps; A type of (often metal covered) spark plug cap found on BMW that have a
resistance of about 5
k Ohms. Designed to reduce radio noise, but the metal covered caps were
collectors of humidity and often shorted out the ignition voltage.
Resistor plugs; Spark plugs with some built in resistance to
reduce radio noise from the ignition system.
Restoration; a BMW restored back to original specifications, not some improved
later technology. See renovation.
Reynolds; Reynolds Machine Tool Co.
makes a variety of BMW accessories out of steel: Luggage racks, ride-off
R-bike centerstand, pillion backrests. Salt Lake City UT. Now out of
rich. Usually refers to the fuel/air mixture when it has more fuel
Rick Mayer. An aftermarket BMW motorcycle seat manufacturer.
Ring(s). A number of rings surround a piston to seal the combustion gasses from
escaping past the piston. Worn out rings will allow the engine to burn
Road rash; The injury from sliding down the pavement.
roller; The rolling part in a roller bearing, as opposed to a ball.
Common to BMW wheels, swing arm and steering.
RS; Acronym for Renn Sport, or racing sport.
RT; Acronym for Road Touring.
S; Acronym for sport and used as a suffix on some models
designations. Ex. R90S
Safety wire; a springy wire used to keep a part from falling off. Not
used by BMW in production, but by racers.
sag; A term to describe springs that have lost some of the original
Scalloping; Also called cupping, as a normal front tire wear on a
Seized; Related to what happens to a piston when it
expands from heat
and becomes too large for the cylinder. It was more common on the /2 era
Setting timing; Adjusting the ignition timing to occur at the best
time in the engine cycle.
Shaft Drive; The drive shaft is how the power gets from the
engine to the rear wheel. Historically, motorcycles used chains.
Recently a single cylinder BMW uses a chain and not a drive shaft. http://motorcycles.about.com/cs/beginners/g/def118.htm
Shaft splines; A series of grooves
cut along the length of a shaft, usually to allow it to transfer rotation
through a counter fitting ring or keyway.
Shimmy; Another term for high speed wobble, see above.
Short circuit; A term meaning that a hot electrical wire is touching
ground, or another part of the circuit. Not a nice thing.
Shorts; See above
sidecar; An outrigger attached to one side of a
motorcycle for carrying passengers or freight. Also called a chair or
Sidestand; The stand that props up a motorcycle at an angle. BMW
has been well known for poor sidestands.
Silicone; A type of plastic rubber commonly used by Silicone James
(inside joke) to
fix just about anything.
single/double/four/six Piston Caliper; For
disk brakes, the caliper holds the abrasive brake pads so that they are on
either side of the brake disc. hydraulic pistons in the caliper squeeze the
pads against the disc causing braking of the disc's rotation.
Single-leading shoe, The front drum brake of a motorcycle has two
shoes. If one is leading and the other is trailing during the
application of braking, then it is called single leading. The best
braking is when both shoes are leading. The twin cylinder BMW
motorcycles since about 1955 have all been double leading. The R25
series, R26 and R27 were single leading type.
sissy bar; The near vertical bar that originally was used for the rear of a motorcycle seat commonly used on a
chopper. Over time the term has evolved to be any
back rest on a
motorcycle. The Reynolds Back Rest was often used on a BMW and is
Skid; As in skidding the tire.
slide; As in sliding the tire..
slider; A Brit term for the leg, or lower casting on
Slop; A term for "play" or "looseness" in an assembly.
snap-ring; Used to retain something on a round shaft. The BMW
used them in several applications.
Snell Helmet Rating; A long time standard for helmet testing and
Snowflakes; A term applied to a style of cast wheel on a BMW starting
in 1978. The first ones were defective and recalled.
Solo seat; A seat for one person that was common on
older BMW motorcycles.
spline; A series of longitudinal
grooves like key seats in a hub or on a shaft, so that while one may slide
endwise on the other, both must revolve together. BMW uses splines for
all drive applications on their motorcycles.
Spoke tension; Referring to how tight a nipple is tightened on a wheel
spoke. BMW motorcycle wheels were all made with
spokes up to 1978 and
some since then. The BMW is well known for not losing spoke tension
because they are straight spokes, not having an angle at one end.
Square Engine; An engine whose
cylinder bore size and piston stroke are equal. A number of early BMWs
had square, boxer engines.
Spun wheel hub; This refers to the wheel bearing spinning in the wheel
hub. Especially common on the rear of the /5, /6 and /7 models.
It usually ruins the aluminum hub.
Squirrelly handling; A slang term for a feeling of less than full
control on a motorcycle.
ST; An acronym Sport Touring used as a suffix on some models. Ex. R80ST
stanchion; A Brit term
for the fork tube.
Standard Bike; http://motorcycles.about.com/cs/beginners/g/def032.htm
Standing on brakes; Application of a lot of braking power, usually in
a panic stop.
Starter dragging; This refers to an electric starter that has high
internal resistance due to bearings or bushings. They must be replaced
to return to easy starting.
Steering damper; A system for adding resistance to the motorcycle
steering. BMW has used two styles, friction and hydraulic.
Stiction; A "new" general engineering term. The term
for the resistance in motorcycle telescopic forks starting to telescope.
A lot of stiction is not good. Caused by bent, twisted or out of
alignment of forks.
Stoppie, stoppy; Stopping so quickly
with the front brake that the motorcycle rises up on its front wheel. A
Stripped threads; Threads that have been damaged and are mostly gone or
sump (Brit) = oilpan (Yank)
swage; A way to fasten something. It is done with pressure
rather than welding or fasteners.
SWB; Acronym for Short Wheel Base.
Swing arm; The arm holding a wheel and allowing to go up and down
on a motorcycle. The Earles fork series, from late 55 thru
69 had a
swing arm in the front as well as the commonly known rear.
Synchronize; On a BMW this term refers to having the two carbs work
together so as to provide smooth operation. Some related info for the
carbs on the /2 motorcycle that also applies to
more modern BMWs.
tachometer; (rev counter in Brit speak) A meter
showing the number of revolutions of a shaft. Usually the revolutions
per minute of the crankshaft.
Tank slapper; Another term for high
speed wobble. The forks oscillate back and forth so much that they
hit the tank with a slap.
Tank; Gas tank or fuel tank. Some of the history of the
and /6 fuel tanks.
tank bag; A bag, or luggage, of some sort that mounts
on the top of the fuel tank. The Harro was the best one.
taper fit; A type of connection between rotating parts. The BMW
uses it on the output of the transmission and at the rear of older drive shafts.
Tapered bearing; A special type of bearing common on BMW wheels, swing
arms and steering.
Target Fixation; http://motorcycles.about.com/cs/beginners/g/def057.htm
Throttle return; This refers to the system for allowing or preventing a
BMW throttle from returning to idle automatically. Sort of a crude
cruise control for the /2, /5, /6 and later
Throttle-Meister; An adjustable
friction system which inserts into the end of the throttle side handlebar
allowing one to keep the throttle set at a certain place.
Timken is the USA company famous for making the
tapered roller bearings.
Tire bead; The edge of the tire that seats against the rim.
BMW had a special rim for keeping the bead on
the rim in a blow out.
Tire direction; Unlike car tires, motorcycle tires have an arrow on
the sidewall showing the direction of travel.
Tire plugs; A system for fixing a flat tire. Not recommended for
a motorcycle. It involves sticking a plug in the nail hole to plug up
Tool kit; BMW is famous for supplying the best tool kit of any
TDC; acronym for top dead center. This is the time in the
cycle of the engine when the piston is at the closest to the head.
It is important in setting the valves on a BMW.
Top end; This refers to the portion of the engine that is above the
crankshaft. The cylinders, pistons and heads make up the top end.
On a BMW boxer, the top end is not at the "top" but out to each
Top hat spacer; A part of the wheel bearing system
used on older BMWs. One example.
Torque; A measure of how tight something
is or should be, as in turning a bolt or nut.
wrench; A tool for showing how tight a fastener is while it is being
Totaled; This refers to any vehicle that is in a crash. The
insurance company finds that the vehicle isn't worth repairing. The
wreck is a "total"
Trail; A measure, in degrees, of the geometry of motorcycle forks.
Trailer Queen.; a motorcycle that is towed to events, rather than being
ridden. A derogatory term.
Transverse; Directional terminology
for an imaginary line across the motorcycle from side to side. BMW flat twin
engines have the cylinders in a transverse direction.
Trickle charging; A way to slowly and gently charge the battery on a
Triple tree; A part of the motorcycle fork assembly.
Troubleshoot; Looking for the problem.
Turkey gobbler; A noise that is loud and embarrassing to the rider of
the /5 BMW motorcycle. The name is because it sounds like a turkey
gobbler. It is related to the crankcase pressure. http://home.jps.net/~snowbum/oilingsystem.htm
Twisties. A term that describes the roads that many BMW riders really
like. The are full of twisted curves and therefore the name.
Two up; This means riding with a passenger.
Undersquare; The design when the diameter of the piston is less
than the length of piston travel. Useful for high torque at low rpm.
Universal joint; A method of transferring power from the transmission
to the rear wheel. Traditionally, BMW has used a drive shaft, while most
other motorcycles used a chain. The drive shaft must have a flexible
part to allow for the travel of the suspension system. This part is the
universal joint or just U-joint.
Valve clearance; Also called valve adjustment or valve lash. This
is the space between the valve stem and the rocker arm. It is part
of a regular maintenance program for your BMW.
Valve lash. Same as valve adjustment, or clearance as shown above.
Valve seat; The part of the cylinder head that the valve head rests
against during combustion.
Valve tuliping; This refers to a process of failure of the valve head.
Soon the head may fall off and greatly damage the BMW head and piston.
Vetter; Manufacturer of aftermarket fairings and luggage for
motorcycles in the 1970s and 80s.
Vibration; While the BMW twin is considered a smooth motorcycle, they
do vibrate at some speeds and rpm.
Vintage; An old BMW motorcycle.
Viscosity; The measure of the thickness of any oil. One must use
the proper viscosity for different times of the year due to temperature
Volt meter to battery; Some of the later BMWs had a volt meter mounted
in the fairing. They were notoriously inaccurate.
Voltage drop; The loss of voltage due to resistance in a wire or
connection. Not a good thing. It can be
reduced by using grease.
Volts; A term for electrical pressure. All BMWs had a 6 volt
system up to the introduction of the /5 in late 69 for the 1970 year models.
Since then they have all been 12 volts.
VOM; acronym for Volt-Ohm Meter, a very handy test instrument for electrical
Waste spark; A term for the type of ignition system used on the BMW
twins. One side or the other gets a "not needed" spark, so it
is called a waste spark.
Watts; A unit of electrical power. Commonly used by owners of
older BMWs, as they didn't offer enough power to run modern accessories.
Wedding ring spacer; An important part of the
wheel bearing system from 1955 thru 1984.
Weinman; Manufacturer of alloy
wheel rims for BMW throughout the 1970s
Went down; Another common idiom for crashing.
Wet Clutch; http://motorcycles.about.com/cs/beginners/g/def166.htm
A fairing manufactured by
Craig Vetter with brackets to fit a BMW. Significant in that this one
product completely changed the industry in the early 70s. This fairing
was copied (stolen) by many others, most notably the Luftmeister.
Wires are fried; Some, or all, of the wires in the wiring harness were
over heated and burned up the insulation. Usually it must be replaced.
On the unfused /5 from 70-71, it was common.
Wiring harness; The term for the collection of wires that are usually
bundled up in some protective tubing. On an old BMW they typically go
from the headlight shell to all other points on the bike.
Woodruff key; A small part that positions one rotating part on another
one. It goes into a keyway or groove. Ex. to position the flywheel
on the crankshaft. Used on older BMWs.
product to allow one to rest the throttle hand on long rides.
Zen; A possible reference to the book, "Zen and the Art of Motorcycle
Maintenance" A combination touring tale and philosophy of life book that
involves a BMW. Read this online
German to English motorcycle terms
English to German motorcycle terms
motorcycle terms listing. Not always applicable to BMW, but may be