ClassicMotorcycleMechanicsJune2020

(Jacob Rumans) #1
The front brake caliper is the same as
thatont he TX500 andafew other
contemporaryYamahas.Itwas in pretty
good shape, butofcourseneedednew
seals, whichare of avery simple design
(Photo 10). The materialisc ast iron so
you canbefairly forcefulwhencleaningit
up. The outside wasquiteacceptable and
evenhad th eoriginal blobsofy ellow paint
on the bolts, showing thatthey hadbeen
correctly tightenedat the factory (Photo
11). Itook thisphoto ,byt he way, to
remindmyself which way roundthe
anti-squealshimswere fitted.EBCpads
were probablyabetter solution than
ancient NOSYamahaitems (Photo12).
One discoveryImade (by reading the
manual properly)was that it isjust
possible to take thecaliper offwiththe
wheel andmudguardinplace (Photo13),
whichhad notoccurred to mebefore.The
reason whythe brakewould notwork was
that t here wasnot enough brown gooin
the mastercylinde r(Photo 14), but it was
easyenough toseewhereith ad gone
(Photo 15).Obviously an overhaul was
required,but whenit came to getting hold
of spare partsIhappened to notice that
the cylinderlooked identical to thatonthe

12

CB750 (Photo 16)–apart from the
screw-on cap—soifitw as the sameon
the outside, maybeitw ould also be on the
inside?An investigation of therelevant
parts books showed that this did seem to
be th ecasesol ogicallyIshouldbe ableto
use easier-to-findCB750 partsforit. After
removing the internalparts they really did
look thesame. Theconclusion then was
that Honda andYamahaused the same
externalsuppli er fo rthe master cylinders,
presumablyTokico.
Genuine Honda brakeparts are very
expensive, butIhavealwayshad perfect
success withgood-qualitypattern parts.
Igot this Japanese-madeTourmax set
(Photo17), whichwas meanttofita
CB750,but worked perfectly for this
application.
One thingIwanttod raw yourattention
to is shown in Photo 18.Herewesee the
twoholes at thebotto mofthe master
cylinder reservoir:abig one andasmall
one. The master cylinder will not work
properlyifeitherone is blocked. A
carburettorjetreaming tool workswellon
the small hole.cmm
■Next timeIhave acloser look at the
braking system.

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15 16

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