Motorcycle Glossary of Terms
Please e-mail us if you have
a glossary term suggestion to add to our motorcycle
Damper - Used for slowing
down movement in suspension system or as a
Daytona - The infamous Daytona
Bike Week held late February to early March
in the USA.
Decarbonisation - The process
of removing carbon deposits - typically from
the combustion chamber, valves and exhaust
Diode - An electrical valve
which only allows current to flow in one direction.
Commonly used in rectifiers and starter interlock
Direct current (dc) - Current
produced by a dc generator.
Disc valve (for rotary valve)
- An induction system used on some two-strole
Displacement - The engine
capacity or amount of volume displaced by
the movement of the piston from bottom dead
centre to top dead centre.
Distributor - A gear driven
contact sending high tension current to spark
Dope - Highly combustable
alcohol/methanol-based fuel mixture.
(DOHC) - An engine that uses two overhead
camshafts, one for the intake valves and one
for the exhaust valves.
Drivebelt - A toothed belt
used to transmit drive to the rear wheel on
some motorcycles. A drivebelt has also been
used to drive the camshafts. Drivebelts are
usually made of Kevlar.
Driveshaft - Any shaft used
to transmit motion. Commonly used when referring
to the final driveshaft on shaft drive motorcycles.
DSA - Driving Standards
Dual sport - street-legal
bikes that provide varying levels of off-road
DVLA - Driver and Vehicle
Licensing Agency. The agency you need to apply
for a driving license.
DVLC - Driver and Vehicle
Dry sump - Two oil pumps,
one supplying oil to the bearings from a tank,
the other to return it to the tank