Fasteners; Types Of Threads; Thread Sizes - Honda Motorcycle Service Manual

GENERAL INFORMATION
FASTENERS
A motorcycle is composed of a number of connected parts. A
variety of fasteners are used t o connect these parts. Unlike
permanent connection methods like welding, riveting and
glueing, threaded fasteners are essential as a means of non-
permanent connection which can be disconnected whenever
necessary.
Roughly estimated, the thread diameter is the O.D. of the male
thread or the I.D. across the full width of the "valleys" of the
female thread.
The pitch is the thread-to-thread distance that a malelfemale
bolt moves i n one complete turn.
TYPES OF THREADS
Metric threads, as specified by the International Standards
Organization (ISO), are used on HONDA motorcycles.
The t v ~ i c a l I S 0 threads found on Honda products are the .
.
following threads and pitches
1
Diameter (mm)
/
Pitch (mml
Diameter (mm)
1
Pitch (mm)
J
The few parts which do not have conventional (60) metric
threads are listed below.
The threads are NOT INTERCHANGEABLE with conventional (ISO) metric threads.
*
The figures given above represent screw sizes. A n example
is given for each type of screw or thread type.
Description
Parallel threads for tubes
Tapered threads for tubes
Thread type used on bicycles
Spark plug threads
Automobile tire
valve stem
THREAD SIZES
1
*Symbols (typical examples)
PF 118
PT 118
BC 3.2
M 1 2 5
TV8
1-6
Date o f Issue: Nov., 1 9 8 9
O
HONDA
MOTOR CO., LTD.
Example of application
Oil pressure switch
Thermostatic units
Spokes and nipples
Spark plugs
Tire valve stem
WIDTH ACROSS
Thread sizes are represented by male thread diameters. Wid-
FLATS
ths across flats represent applicable tool sizes. Note that these
1
(TOOL SIZE)
widths are not related t o thread sizes.
On Honda motorcycles, scooters and ATVs, the size of the
bolt, nut or screw is considered t o be the thread diameter.
MALE THREAD DIAMETER
(THREAD SIZE)