BRITISH STANDARD AUTOMOBILE SERIES BS AU 193a 1990 (Superseding BS AU 193 1983) Specification for Replacement motor cycle and moped exhaust systems BS AU 193a 1990 This British Standard, having been p[.]
Trang 1(Supersed ing
BSA U19 :19 3)
Trang 2This British Stan ard, ha ing
b en pre ared u der the
directionof the Automo ile
Stan ards Policy Commite
waspublished u der the
authorityof the Bo rd of BSI
an comes into efect on
2 Ju e1 9
© BSI 0 -1 9
Fir t published Se temb r 1 8
Secon edition Ju e 1 9
The folowing BSI references
relate to the work on this
stan ard:
Commite reference AUE/9
Draft for comment 8 / 76 3 DC
The prep ration of this British Stand rd was entrusted b the Automobi e
Stand ards Pol cy Commit e ( AUE/-) to Tech ical Commit e AUE/9, upon
which the fol owing bod ies were represented :
Automobi e As ociation
Consumer Pol cy Commit e of BSI
Dep rtment of Trad e an Ind ustry ( Consumer Safety Unit, C A Div ision)
Dep rtment of Transport
Garag e Equipment As ociation
Institute of Tra ing Stand ards Administration
Motor Ag ents As ociation Ltd
Motor Cy cle Ind ustry ’s Association of Great Britain Ltd
Roy al Automobie Club
Society of Motor Man facturer and Tra er Ltd
Am endm ents is ued sinc publ cation
Amd No Date of is ue Comments
Trang 3Pag e
Ap end ix B Conditioning of exhaust sy stems containing
Fig ure 1 — Test a p ratus for conditioning b pulsation 7
Fig ure 2 — Ar ang ement of test for measuring motor cy cle
Ta le 1 — Ma imum noise lev el for motor cy cles or mopeds of ty pe A 2
Ta le 2 — Ma imum noise lev el for motor cy cles or mopeds of ty pe B 2
Ta le 3 — Ma imum noise lev el for motor cy cles or mopeds of ty pe C 2
Ta le 4 — Distances to be completed d uring conditioning 3
Ta le 5 — Number of test bench cy cles to be completed b each clas
Trang 4This British Stand ard has be n prep red u der the direction of the Automobie
Stand rd s Pol cy Commit e with the as istance of the Dep rtment of Transport
It super ed es BS AU19 :19 3, which is withd rawn This rev ision reflects the
Dep rtment of Transport’s a option of the d irectiv e7 / 1015/ EEC, amended b
the directiv es 8 / 56/EEC and 8 /23 / EEC, on noise lmits an replacement
siencer
This British Stand rd difer fom the prev ious edition in that the folowing items
hav e be n included:
a) definitions of motor cy cle of ty pe C ( se 2.3) an moped of ty pe C ( se 2.6);
b) ma imum noise lev els for ty pe C machines ( se 5.3);
c) a method to cond ition exhaust sy stems b pulsation ( se B.3)
A British Stand ard d oes not purport to includ e al the neces ary prov isions of a
contract User of British Stand rd s are responsible for their cor ect a plcation
Com pl anc with a British Standard does not ofitself confer im m unity
f om leg al o l g ations
Sum mary of pag es
This document comprises a f ont cov er, an insid e font cov er, p g es i an i ,
p g es1 to8, an inside b ck cov er and a b ck cov er
This stand rd has be n up ated ( se copy rig ht d ate) an ma hav e ha
amendments incorporated This wi l be indicated in the amendment ta le on the
inside f ont cov er
Trang 51 Scope
This British Stand ard specifies req uirements for the
siencing properties of replacement exhaust sy stems
or p rts there f for instal ation on motor cy cles and
mopeds It des ribes methods for measuring the
noise emit ed b motor cy cles and mopeds fit ed
with these sy stems and specifies req uirements for
the dura i ty of fibrous noise a sorbing materials
where these are used to me t the noise l mits.It also
includes req uirements for marking these exhaust
sy stems an their p ckag ing an for the sup ly of
instalation l terature
NOT The tites of the publications refered to in this stan ard
are listed on the inside b ck co er
2 Definitions
For the purposes of this British Stand rd the
fol owing d efinitions a ply
2.1
motor cycle of ty e A
a mechanical y propeled v ehicle, not being an
inv al d car iag e, with les than four whe ls and an
u lad en mas that do s not exce d4 0kg , fir t
used betwe n1Apri 19 0and31 Mar h19 3
2.2
m otor cycle of ty e B
a two-whe led v ehicle, with or without sidecar,
fit ed with an eng ine intended for use on the
roa and hav ing a ma imum desig n spe d
ofmorethan5 km/ h, fir t used
betwe n1Apri 19 3and31Mar h19 1
2.3
m otor cycle of ty e C
a two-whe led v ehicle, with or without sidecar,
fit ed with an eng ine intend ed for use on the road
and ha ing a ma imum desig n spe d of more
than5 km/h, fir t used on or after1Apri 19 1
2.4
m oped ofty e A
a two-whe led or thre -whe led v ehicle fir t used
betwe n1Apri 19 0and31Mar h19 3that has
a ma imum desig n spe d not exce d ing5 km/ h, a
kerb-side mas not exce ding25 kg and , if
propeled b an internal combustion eng ine, an
eng ine ca acity not exce ding5 cm
3
2.5
m oped ofty e B
a two-whe led or thre -whe led v ehicle fir t used
betwe n1Apri 19 3and31Mar h19 1that has
a ma imum desig n spe d not exce d ing5 km/ h, a
kerb-side mas not exce ding25 kg and , if
propeled b an internal combustion eng ine, an
eng ine ca acity not exce ding5 cm
3
2.6
moped of type C
a two-whe led or thre -whe led v ehicle fir t used on
or after1Apri 19 1 that has a ma imum desig n
spe d not exce ding5 km/ h, a kerb-side mas not
exce ding25 kg and, if propeled b an internal
combustion eng ine, an eng ine ca acity not
exce ding5 cm
3
2.7
exhaust system
a complete set of components throug h which the
exhaust g ases es a e f om the eng ine unit,
including those that are neces ary to l mit the noise
caused b the es a e of these g ases
2.8
fibrous materials
materials of a fibrous nature that are placed within
the exhaust sy stem to lmit the noise caused b the
es a e of the exhaust g ases
2.9
maxim um rated power spe d (S)
the eng ine spe d at which the motor cy cle or moped
d ev elops ma imum power
3 Genera l
Exhaust sy stems shal be tamper-resistant so far as
ma be comp tible with clearly d efined
maintenance and instal ation req uirements
4 Fibrous m a teria l
4.1 Fibrous material shal not be used in the
man facture of exhaust sy stems u les it is
asbestos-f e and comples with4.2or4.3 In
a d ition, means shal be prov ided to ke p the
fibrous material in place
4.2 The exhaust g ases shal not be directed throug h
the fibrous material The fibrous material shal
hav e a dura i ty commensurate with the exhaust
sy stem and shal comply with Ap endix A
4.3 Exhaust sy stems containing fibrous a sorbent
material shal be prep red for testing in ac ord ance
with Ap endix B, or b remov ing the fibrous
material fom the exhaust sy stem
5 Perm is ible noise level
5.1 The max imum noise lev el for motor cy cles or
mopeds of ty pe A, when tested in ac ord ance
withC.4.2.2, shal be as g iv en in Ta le 1
Trang 6Ta le 1 — Maxim um noise level for m otor
cycles or m opeds of ty e A
5.2 The ma imum noise lev el for motor cy cles or
moped s of ty pe B, when tested in ac ord nce
withC.4.2.3, shal be as g iv en in Ta le 2
Ta le 2 — Maxim um noise level for m otor
cycles or m opeds of type B
5.3 The ma imum noise lev el for motor cy cles or
moped s of ty pe C, when tested in ac ord nce
withC.4.2.4, shal be as g iv en in Ta le 3
Ta le 3 — Maxim um noise level for m otor
cycles or m opeds of type C
6 Ma rking a nd pa ckag ing
6.1 Each si encer of an exhaust sy stem shal be
clearly and ind elbly marked with the folowing
information in a position such that it is rea i y
v isible when fit ed to the motor cy cle or moped:
a) the n mber and d ate of this British Stand rd
an an indication of which of the thre
testsinAp endix C was used,
i.e BS AU19 a:19 0
1)
/T1, /T2or/T3;
b) the reg istered name or tra e mark of the
exhaust sy stem man facturer
The man facturer’s p rt n mber shal also be
clearly an ind elbly mark ed on each component of
the exhaust sy stem ( excluding fixing s)
6.2 The exhaust system shal be sup l ed with
p ckag ing , or la el ing , which shal be clearly and
ind elbly marked with the folowing information:
a) the n mber and d ate of this British Stand rd
an an indication of which of the thre
testsinAp endix C was used,
i.e.BSAU19 a:19 0
1)
/T1, /T2or/T3;
b) the reg istered name or tra e mark and ad dres
of the exhaust sy stem manufacturer or, in the
case of imported g ood s, those of the UK sup l er;
c) a l st of the specific motor cy cle or moped
models for which the sy stem is suita le
In a d ition,the man facturer of the exhaust sy stem
shal sup ly instructions that detai the cor ect
method of at achment to the motor cy cle or moped,
instructions for maintenance of the exhaust sy stem
and a l st of component p rts with the
cor espond ing p rt n mber ( excluding fixing s)
E g ine ca acity Ma im um noise
level
cm 3
dB( A)
Mopeds
Motor cy cles not exce d ing 5
Motor cy cles g reater than 5
but not more than 1 5
Motor cy cles g reater than 1 5
7
7
82
8
E g ine ca acity Ma im um noise
level
cm 3
dB( A)
Motor cy cles not exce d ing 8 7
Motor cy cles g reater than 8
Motor cy cles g reater than 1 5
Motor cy cles g reater than 3 0
Motor cy cles g reater than 5 0 8
E g ine ca acity Ma im um noise
level
cm 3
dB( A)
Mopeds
Motor cy cles not exce d ing 8
Motor cy cles g reater than 8
but not more than 17
Motor cy cles g reater than 17
7
7
7
82
1)
Marking BS AU1 3 :1 9 on or in relation to a prod ct re resents a man facturer’s declaration ofconformity,i.e a claim b
or on b half of the man facturer that the prod ct me ts the re uirements of the stan ard The ac uracy of the claim is therefore
solely the resp nsibility of the p ron making the claim S ch a declaration is not to b confused with third p rty certification of
conformity, which ma also b desira le
Trang 7Appendix A Tests for dura bi ity of
fibrous m a terial
A.1 The material shal withstand a temperature
of6 0 ± 5°Cfor4h in a mufle furnace without
red uction of av erag e fibre leng th, d iameter of fibre
or bulk density
A.2 After heating at6 0 ± 5°C for1h in a mufle
furnace, at least9 % of the material shal
beretained in a siev e of nominal a erture
siz 25 4m ( 60mesh) comply ing withBS410
whentested in ac ord nce with BS17 6
A.3 The los in mas of material shal not
exce d10.5 % after soaking for24h at9 ± 5°C in
sy nthetic exhaust condensate of the fol owing
composition:
NOT The material should b washed in distiled water an
dried for1h at1 5°C b fore weighing
Appendix B Conditioning ofexha ust
system s containing fibrous m aterial
B.1 General
Before testing in ac ord ance with Ap endix C,
exhaust sy stems containing fibrous material shal
either be cond itioned in ac ord nce withB.2, B.3
orB.4or the fibrous material shal be remov ed
B.2 Continuous ro d o eration
B.2.1 The minimum distances to be completed b
moped s an motor cy cles during cond itioning shal
be as g iv en in Ta le 4 Town driv ing shal ac ou t
for5 ± 10 % of the operation an long -d istance
ru s shal ac ou t for the remainder
NOT Contin ous ro d o eration ma b re laced b a
cor esp n ing track pro ramme
Ta le 4 — Distanc s to be com pleted during
conditioning
B.2.2 Town d riv ing an long d istance ru s shal be
alternated on at least six oc asions
B.2.3 The complete test prog ramme shal include a
minimum of10 breaks, each of at least3h,in ord er
to reproduce the efects of co l ng and any
condensation
B.3 Conditioning by pulsation
B.3.1 The exhaust sy stem shal be fit ed to the
motor cy cle or to the eng ine In the former case, the
motor cy cle shal be mou ted on a roler
dy namometer In the lat er case, the eng ine shal be
mou ted on a test bench
The test a p ratus shal be fit ed at the outlet of the
exhaust sy stem
NOT A ty ical test a p ratus is shown in Figure 1 but other
a p ratus that prov ides e uiv lent resuls ma b used
B.3.2 The test equipment shal be a justed so that
the flow of exhaust g ases is alternately inter upted
and restored25 0times b a ra id -action v alv e
B.3.3 The v alv e shal open when the exhaust g as
b ck-pres ure, measured at least10 mm
downstream of the intake flang e, reaches a v alue of
betwe n 0.3 b r
)
and0.4 b r I such a fig ure is
u at aina le because of the eng ine characteristic ,
the v alv e shal then open when the g as
b ck-pres ure reaches a lev el eq uiv alent to9 % of
the ma imum that can be measured before the
eng ine stops It shal close when this pres ure do s
not difer b more than10 % f om its sta i iz d
v alue with the v alv e open
B.3.4 The time-d ela switch shal be set for the
duration of the exhaust g ases calculated on the
b sis of the requirements in B.3.3
B.3.5 Eng ine spe d shal be7 % of the ma imum
rated power spe d ( S)
B.3.6 The power ind icated b the dy namometer
shal be5 % of the ful -throt le power measured
at7 % of S
B.3.7 Any d rainag e holes shal be closed of d uring
the test
B.3.8 The entire test shal be completed within4 h
I neces ary , a co lng period shal be alowed after
each hour
B.4 Conditioning on a test bench
B.4.1 The exhaust sy stem shal be fit ed to an
eng ine representativ e of the ty pe fit ed in the motor
cy cle or moped for which the sy stem is d esig ned ,
coupled to a d y namometer
B.4.2 Cond itioning shal consist of the specified
n mber of test bench cy cles for the clas of motor
cy cle or moped for which the exhaust sy stem is
intended The number of cy cles for each clas of
v ehicle shal be as g iv en in Ta le 5
hy drobromic acid c ( HBr) = 1 mol/ L 10 mL
sulphuric acid c ( H
2 SO
4 ) = 5 mol/ L 10 mL
d isti led water to make up to 10 0 mL
cm 3
km
Motor cy cles not exce d ing 8
Motor cy cles g reater than 8
butnot more than 17
Motor cy cles g reater than 17
40 0
60 0
80 0
2)
1b r = 1 0kN/ m
2
= 1 0KPa
Trang 8Ta le 5 — Num ber of test bench cycles to be
com pleted b each clas of motor cycle or
m oped
Each test bench cy cle shal be folowed b a break of
at least6h in order to reprod uce the efects of
co l ng and any condensation
B.4.3 Each test bench cy cle shal consist of six
phases The eng ine conditions for, an the d uration
of, each phase shal be as g iv en in Ta le 6
Ta le 6 — One test bench cycle
Appendix C Methods ofm ea suring
noise levels
C.1 Preparation of m otor cycle or m oped for
test
C.1.1 The motor cy cle or moped shal comply with
the man facturer’s specification for the mod el for
which the exhaust sy stem is intended with the
exception of any alterations neces ary to
ac ommod ate the item( s) u der test
C.1.2 I the motor cy cle or moped is fit ed with fans
with an automatic actuating mechanism, this
sy stem shal not be inter ered with For v ehicles
hav ing more than one d riv en whe l, only the d riv e
for normal road operation shal be used
N T W here a motor cycle is fited with a sidecar, this should
where p s ible, b remo ed for the purp se of the test
C.1.3 W here an exhaust sy stem is intended for use
on sev eral v ariants of a motor cy cle or moped b sed
on the same eng ine ty pe and ca acity but with
difering power outputs, a wor t case v ehicle shal
be selected
N T The wor t case v ehicle is g neraly taken as the v ariant
with the hig hest engine p wer for that model, but other factor
that could afect the o eral noise le el, such as o eral g earing
an intake sy stems, should b taken into ac ou t in the selection
C.2 Test site
C.2.1 The test site shal consist of a central
ac eleration area sur ou d ed b a substantialy flat
area The ac eleration area shal be flat and its
surace shal be such that rol ng noise is
consistently low
The test site shal be such that hemispherical
div erg ence exists to within ± 1dB( A) betwe n
asou d sour e at the centre of the test area
and mic ophone, i.e the sou d rad iation is
within±1 d B( A) of the the retical v alue for a point
sour e on a plane reflecting sur ace
N T This con ition is satisied if there are no larg o jects
that reflect sou d, such as fences, rocks, bridg es or buildings,
within5 m of the centre of the test are
The surace of the site shal be mad e of hard
material, such as conc ete or asphalt, within a
minimum ra ius of10m arou d the centre of the
test site and shal be f e of powdery snow, tal
g ras , lo se soi and cinder
The mic ophone shal not be obstructed in any wa
that could afect the sou d field , and no per on shal
stan betwe n the mic ophone an the soun
sour e
The observ er car y ing out the measurements shal
so position himself as not to afect the rea ing s of
the measuring instrument
C.2.2 Measurements shal not be taken in
u fav oura le meterolog ical cond itions nor in
g usting wind s
C.2.3 For measurements, the A-weig hted sou d
lev el ( se BS5 6 ) of soun sour es other than
those of the motor cy cle or moped to be tested or of
wind efects shal be at least10dB( A) below the
sou d lev el prod uced b the v ehicle
N T A suita le win s re n ma b fit ed to the mico hone
pro ided that ac ou t is taken of its efect on the sensitivity an
directional characteristic of the mico hone
C.3 Apparatus
C.3.1Pr ecision sou d l evel meter , comply ing at least
with the req uirements for ty pe1of BS5 6 , or
comply ing with the specification of the meter for the
orig inal motor cy cle’s a prov al procedure
cycles
cm 3
Mopeds
Motor cy cles not exce d ing 8
Motor cy cles g reater than 8
but not more than 17
Motor cy cles g reater than 17
3
6
9
1
of phase
E gines
not a o e
1 5 cm 3
E gines
a o e
1 5 cm 3
a
b
c
d
e
f
id ling spe d
25 % loa at 7 % of S
5 % loa at 7 % of S
10 % load at 7 % of S
5 % loa at 10 % of S
25 % loa at 10 % of S
6
4
4
3
1
2
6
5
5
10
1
2
NOT During con itioning, at the re uest of the
man facturer,the engine an silencer ma b co led in order
that the temp rature recorded, at a p int no more than1 0mm
fom the ex haust p rt outet, when the motor cy cle or mo ed is
ru ning at1 0km/ h or7 % of S in to g ear, whichev er is the
les er, is not e ce ded The eng ine an /or motor cycle or mo ed
sp ed an lo d are determined to within ± 3 %
Trang 9C.4 Proc dure
C.4.1 Met hod o measurement
Before any measurements are mad e, bring the
motor cy cle or moped eng ine to the normal operating
temperature
Car y out acoustic measurements using the fast
response time and the A-weig hting curv e At the
beg in ing and end of each series of measurements,
calbrate the soun lev el meter in ac ord nce with
the man facturer’s instructions using a suita le
soun sour e, e.g a pistonphone
Using the precision sou d lev el meter ( C.3.1),
measure the ma imum sou d lev el in A-weig hted
decibels [ dB( A)] as the motor cy cle or moped is
driv en betwe n l nes AA and BB ( se Fig ure 2)
Ig nore any peak v alue that is obv iously out of
character with the g eneral sou d lev el shown on the
instrument
Locate the mic ophone on reference lne
PP,7.5±0.2 m f om reference l ne CC
( se Fig ure 2) of the track and1.2 ± 0.1m a ov e
theg rou d Ensure that the ax is of ma imum
sensitiv ity is horiz ntal and perpend icular to the
p th of the v ehicle ( line CC)
Ensure that the test motor cy cle or moped
a proaches lne AA at an initial stea y spe d as
des ribed inC.4.2 W hen the font end of the v ehicle
reaches lne AA, open the throt le as quickly as
pos ible to the fuly open position Maintain this
position u ti the rear end of the v ehicle reaches l ne
BB Return the throt le as q uickly as pos ible to the
idle position
C.4.2 Ap r ach condit ion
C.4.2.1 Genera l In the case of an exhaust sy stem
desig ned for use on a motor cy cle or moped of ty pe A,
ensure that the test machine a proaches l ne AA in
ac ord nce withC.4.2.2.1, C.4.2.3.1 orC.4.2.4.1, as
requested b the exhaust sy stem man facturer In
the case of an exhaust sy stem desig ned for use on a
motor cy cle or moped of ty pe B, ensure that the test
machine a proaches lne AA in ac ord nce
withC.4.2.3.1 orC.4.2.4.1 In the case of an
exhaust sy stem d esigned for use on a motor cy cle or
moped of ty pe C, ensure that the test machine
a proaches lne AA in ac ord nce with C.4.2.4.1
For al measurements, d riv e the motor cy cle or
moped in a straig ht lne ov er the ac eleration
section in such a wa that the long itud inal median
plane of the machine is as close as pos ible to l ne
CC
Measure sy stems with a justa le elements that
could afect their eficiency in the conditions of
max imum noise lev el
C.4.2.2 Te t 1: mea surement o the per mis ibl e nois
l evel from a moto cycl e o moped o type A
C.4.2.2.1 Ensure that the motor cy cle or moped
a proaches lne AA at a stea y spe d that is the
lowest of the fol owing :
a) a spe d cor espond ing to7 % of the ma imum
rated power spe d (S);
b) a spe d cor esponding to 7 % of the eng ine
spe d permit ed b the g ov ernor;
c) a roa spe d of5 km/h
Determine the eng ine and / or motor cy cle or moped
spe d to within ± 3 %
C.4.2.2.2 I the motor cy cle or moped is fit ed with a
non-automatic g earbox with no more than four
spe d s, use secon g ear I it is fit ed with a
non-automatic g earbox with more than four spe d s,
use third g ear
Do not eng ag e auxi iary step-up g ear ( “ ov erdriv e”)
I the v ehicle is fit ed with an auxi ary red uction
g earbox, use the lat er with a g ear ratio that al ows
the hig hest v ehicle spe d
C.4.2.2.3 I the motor cy cle or moped is fit ed with
an automatic g earbox with a selector hav ing
alternativ e forward driv e positions, test in the
position that results in the hig hest sou d lev el on
the v ehicle betwe n lnes AA and BB
Exclude the selector position that is used only for
eng ine braking or for p rking or simi ar slow
mano uv res of the motor cy cle or moped
I the transmis ion is prov id ed with ful man al
ov er id e, car y out an a d itional test in ac ord nce
withC.4.2.2.2
I the motor cycle or moped is fit ed with a man aly
operated auxi iary reduction g earbox,use this in the
ratio alowing the hig hest v ehicle spe d
C.4.2.3 Te t 2: mea surement o the per mis ibl e nois
l evel from a moto cycl e o moped o type B
NOT At the re uest of the e haust sy stem man facturer this
method ma b used for motor cycles or mo eds fir t used prior
to April1 8
C.4.2.3.1 Ensure that the motor cy cle or moped
a proaches lne AA at a stea y spe d that is one of
the fol owing :
a) les than 5 km/h, the spe d of rotation of the
eng ine being eq ual to7 % of S;
b) 5 km/h, the spe d of rotation of the eng ine
being betwe n5 % and7 % ofS;
c) more than 5 km/ h, the spe d of rotation of the
eng ine being eq ual to5 % of S
Determine the eng ine and/or motor cy cle or moped
spe d to within ± 3 %
Trang 10C.4.2.3.2 I the motor cy cle or moped is fit ed with a
non-automatic g earbox with not more than four
ratios, eng ag e second g ear
I the motor cy cle or moped is fit ed with a
non-automatic g earbox with more than four ratios:
a) eng ag e the third g ear for v ehicles with a cubic
ca acity of not more than3 0cm
3
b) eng ag e the second g ear for v ehicles with a cubic
ca acity of more than3 0cm
3
I the motor cy cle or moped is fit ed with an
automatic g earbox with a selector, ensure that the
selector is in the position immedi ately below the
position cor esponding to the max imum spe d of the
v ehicle
C.4.2.4 Te t3: mea surement o the permis ibl e nois
l evel from a moto cycl e o moped o type C
NOT At the re uest of the e haust system man facturer this
method ma b used for motor cy cles or mo eds firt used prior
to April1 9
C.4.2.4.1 Ensure that the motor cy cle or moped
a proaches lne AA at a stead y spe d that is one of
the folowing :
a) for machines fit ed with a non-automatic
g earbox, the lowest of:
1) 5 km/h;
2) an eng ine spe d cor esponding to7 % of S;
b) for machines fit ed with an automatic g earbox
without man al ov er ide, whichev er produces the
hig hest sound lev el:
1) 5 km/h;
2) 4 km/h;
3) 3 km/h;
4) 7 % of its ma imum roa spe d if this v alue
is lower;
c) for machines fit ed with an automatic g earbox
with a man al ov er ide:
1) les than 5 km/h, the spe d of rotation of
the eng ine being eq ual to 7 % of S; or
2) 5 km/h, the spe d of rotation of the eng ine
being les than7 % of S; if a chang e-d own
tofir t g ear oc ur , a proach at a spe d of
upto6 km/h suficient to av oid such a
chang e-d own
Determine the eng ine and/or motor y cle or moped
spe d to within ± 3%
C.4.2.4.2 I the motor cy cle or moped is fit ed with a
non-automatic g earbox with not more than four
ratios, eng ag e second g ear
I the motor cy cle or moped is fit ed with a
non-automatic g earbox with more than four ratios:
a) for v ehicles with a cubic ca acity of not more
than17 cm
3
, eng ag e third g ear;
b) for v ehicles with a cubic ca acity of more
than17 cm
3
, eng ag e second g ear and then
repeat the test eng ag ing third g ear
I, during any test conducted in second g ear, the
eng ine spe d is more than1 0 % of S as the machine
a proaches l ne BB, the test is to be cond ucted in
third g ear
I the motor cy cle or moped is fit ed with an
automatic g earbox with man al ov er ide, ensure
that the selecto is in the hig hest position consistent
with the av oid nce of an automatic chang e-d own
( kick-d own)
C.5 Re ording of results
C.5.1 For a motor cy cle or moped tested in
ac ord nce withC.4.2.2, measurements shal be
ma e on at least thre ru s in each d irection The
rea ing s on a g iv en side of the v ehicle shal be
within3d B( A) I the rang e of read ing s on any one
side exce ds3d B( A), the whole test shal be
repeated
The arithmetic mean of each set of thre read ing s on
either side of the motor cy cle or moped shal be
calculated The hig hest av erag e, to the nearest
d ecibel shal be taken to be the sound level of the
v ehicle
C.5.2 For a motor cy cle or moped tested in
ac ord nce withC.4.2.3at least two measurements
shal be taken either side of the v ehicle
Read ing s shal be rou ded to the nearest d ecibel
Only measurements hav ing v ariations in two
consecutiv e tests on the same side of the machine of
les than or equal to2dB( A) shal be v ald
To take into ac ou t inac uracies in the
measurements, the results of each measurement
shal be ar iv ed at b deducting1dB( A) fom the
meter rea ing
The hig hest of the four results recorded shal be
taken to be the sou d lev el of the v ehicle
C.5.3 For a motor cy cle or moped tested in
ac ord nce withC.4.2.4at least two measurements
shal be taken either sid e of the v ehicle I the
prov isions ofC.4.2.4.2 b) a ply , each measurement
shal be taken to be the mean of two consecutiv e
read ing s taken with the second g ear and then the
third g ear eng ag ed
Read ing s shal be rou ded to the nearest d ecibel
Only measurements hav ing v ariations in two
consecutiv e tests on the same side of the machine of
les than or equal to2dB( A) shal be v ald
To take into ac ou t inac uracies in the
measurements, the results of each measurement
shal be ar iv ed at b deducting1dB( A) fom the
meter rea ing
The hig hest of the four results recorded shal be
taken to be the sou d lev el of the v ehicle