ClassicMotorcycleMechanicsJune2020

(Jacob Rumans) #1

Sendyourqueriesto:bsimmonds@mortons.co.ukorwritetoProblemSolver, CMM,PO Box99,Horncastle,LincsLN 96 LZ


1999 HONDA
VFR800Fi

Q:


Ihave a1999 VFR800 Anniversary
Honda.Ihave ownedit for 12
years andit ha sbeen very reliable.Butas
all VFR Hondas do, thecharging system
has been playingup.
Ireplaced the alternator about five years
ago with an OEMunit from the USA and
that seemed to solve theproblem. Then I
hadmore problems with chargingand I
replaced thereg/r ectifier withareplica and
then with an OEMHonda one.Still the
battery would go flatrunninground town
andrequire trickle charging nowand again.
EventuallyIreplaced the reg/rec withan
ElectrexWorld one as it hadworked so
well on my RC30.Thatwas grea tfor about
two months, whenIhad atotal electrical
failuretraced toabroken wiring loom.
When th ebiked stopped thebatter ywas
fully charged, but there wasno suppl yto
the ignition/fuel injectioncircui torthe
headlight.Irepaired that, but eversince
the charging systemhas no tworked. I
replaced theElectre xWorld reg/rec under
warranty,but still nogood .The batteryis
an AGM Motobattype and it holds its
charge welland shows no problems with
the trickle charging.
Iget abou t40voltsfrom each phase of
thealternator on open circuit. Thereis
continuitybetween phase sand open circuit
toearth. Theoutput of the reg/rechas
continuity to the batteryand open circuit to
earth, and theearth is ok.When Iconnect
it al lup, no chargingvoltage appears atthe
battery andthe reg/recheats up quickly,
andsodoes thewiring tothealternator.
The alternator voltage drops toabout nine
volts when under load.Thereis, therefore,
alarge current flowing from thealternator
through theRR, but nothing is getting to

the battery. Just to add to the mystery,the
30 ampfuse in the charging circuit blew
whenthe OEMreg/recwasfitted and both
headlamp bulbs blew.
What is going on? The wiring loom
failure isthestrangest thing: the
connections from the starter solenoidto
the fuse block wasanopencircuit.The
solenoids were allok.That means that two
wireswere broken simultaneously in the
loom.Isoldered in two replacement wires
to the fuse block.That has workedfine
ever since.
Sam Bateman

A:


Youcertainly do seemtobegoing
through the regulator/rectifiers and
Iamsure they are notthatunreliable. It
does sound like there must beashort-
circuit somewhere, but let ustake it
step-by-step. The firstthing is to fully
chargethe batteryand measureits
voltage, which shouldbe over12.6 V. If
you havethe time,without it being
connected to the bike youcouldmeasure
the voltage overaweek orso just to make
sure that it is holding itscharge. Then
connect it tothebikethrough your
multimeter settomilliamps(without the
ignition) and seeifthereisa ny current
flowing, which would of course flatten the
battery.Hondaspecifyamaximum leakage
current of 1.2mA;Iamassuming thatyou
do no thaveanalarm fitted,by the way.If
there is an unacceptableleakage, then
there isashort or the rectifier iskaput.
Your open-circuit voltage readingsfor
the outputs ofthestatorcoilsseem abit
low to me asIwould expectit to be more
like 50V.The re sistancebetw een each pair
of yellow wiresshould be (Hondasay)
between 0.1 and1Ohm, which seems

ratherabroadspecification.Itwould be as
welltoc heckall the diodesthatform the
rectifier by using the setting on your
multimeter: youshould havesixreadings
altogether.Two other useful tests canbe
carr iedout when th eengineis running.
With the engine idling,connectthe
multimeter set toDC volts andputone
leadonared/white wire connector near
thereg/rec and the other onthebattery
positiveterminal. Now connect between a
green wireterminalandthe battery
negative terminal. Thereadinginboth
cases should be less than 200mV.
Iamgoing to look atafew tests for
charging circuit faults inaforthcoming
article.

S d


Our veryown wizened sages, MessrsMark HaycockandSteve
Cooper,are here to answer all of yourwoes,bet hey mechanical
or

2003 SUZUKI SV1000S


Q:


Iown a2003
SV1000 with a
charging fault.lhave
found the stator coil is
faulty; these are easily
available, but the
problem is that one
magnet in the rotor has
come unstuckand been
chewed up in the magneto. Solneed
either someone who can recondition the
rotor or possibly another rotor.The oil
came out clean and the rotor was covered
in magnetic particles so it looks like the
engine is fine, saving me £464 for a
spare one! What do you think?
Richard Fulbrook

A:


Iamafraidthatfailure of the
alternator(or‘magneto’ as
Suzuki call it forsome reason) rotoris
quite commononthesemodels. What
happensiso ne or more magnets detach
and endupbeing chewed up, which is
avery unsatisfactory stateofa ffairs.
Even more unsatisfactory,inmyview,is
thatapparently Suzuki donotaccept
thatthere is anythingwrong withthe
design or construction of this part and
hence it was not subject toarecall.Ido
note, however,that the Suzuki part
number changed from 3210216G00 to
3210216G10, indicating that some
modification did take place.
Iimagine thatthe modificationwas
‘glue themagnets on properly this
time'!Itseemsthatthe adhesive just
wasnot durable enough.Youcan carry
out afixyourself by sticking on
detached magnets. Theonlytrouble is
thatSuzuk idonot offernewonesas
spareparts (why wouldthey as they
think there is nothing wrong!).
Youwill need to get hold of some
second-hand parts andthen use a
high-qualityepoxy resin, perhaps
Loctite. Also check thattheother
magnets aresecure.

46 /classic motorcyclemechanics


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