Classic Dirt Bike – August 2019

(lu) #1
Above:TheARMAC fuel tank isfitted with a
GasGas cap, it doesn’tleak,orp op open as other
typescan.The pi pe is abreatherthatequalises
pressure.
Left:At therear sitapair of NJBshocks, setup by
thelateRichardThorpeofPJ1 Oils.Danfindsthe
suspension to his tast e.
Right:Slimmingdownthe engine is achieved by
removing theouter casingand blocking up the
drain hole s.

14 |AUTUMN


throughout the engine havebeendone,so
thebottom end issound. Mountedonthe
crankcases is analloybarrel madebyMax
Heyesand thekick-start shaftisfromthe
samesource.Maxre-splinesastandard
shaftsoit can takeaMontesa4RT
kick-start, an item thattucks inbetter
than thestandardkick-start. It willbe
obviousfromthe pictures that somework
hasbeen donetoallowthe outer case
on the timingside to beremovedandto
slimdownanalreadyslimengine. For
someonewithengineering facilitiesthis
isn’tadifficultjobso theyall say–hah!
What isrequired is toblockupthedrain
holes,fitablind bushontheend of the
camshaftandfitaplatewithan‘o’ ringto
sealthelayshaft andthe clutchlightener
does thesamejobonthe mainshaft. Once
this isdone noneofthe vitalPutoline oil
canescape,although thereissome ‘mist’
through thebreather.
Thereisall sortsoffolkloreabout cams
in Cubworld, Davehastried the fullrange
in theyears he’sbeen involved withCubs
and hassettled onthe standardroadcam.
“The trials camis okaybutabit clattery,”
he allows. Thereare trialsgears in the box
that giveawider spreadof ratios,though
an initialproblem with thegearbox
tighteningupwastraced to modern
machiningtolerances beingalot closer
than theglorydaysof Meriden and it is
essential tofitpairs of cogsand ensure
thebike is settledin. Providingdriveon
theother side isaSimplexset-up using a
TriumphTerrierengine sprocketand an
ARMACclutchwithaPVLignition making
theall-important spark at the plug.Iasked
whether therewas anythingfancyinthe
cylinderhead.“No,not really,it’shadnew
valvesand guides, butit’stothe standard
road dimensions.”
Feeding the super unleadedfuel into
theinlet port isamodern AmalPremier
carburettor and the settings havebeen
arrivedatbyyearsof knowledgeand

DaveThorpe,YorkshirebornandbredandforgedinSheffield,hasadrysenseofhumour,very
dryinfactandIwascaughtbyitontheday.AswechattedDavecasuallymentioned:“Iwere
goingtobeaworldchampmotocrossery’know...”Knowingridersfromhiseraoftencompeted
inmanydisciplines,Ireplied:“Oh,that’sinterestingtoknow,”andscribbleditdown.DanThorpe
islesspractisedatkeepingastraightfaceandthepennydropped,the‘other’DaveThorpe–
whowasworldMXchamp–isoccasionallyconfusedwithtrialsridingThorpe.Anyway,Dave’s
careerhasincludedworldtrialswinswhenhejoinedBultacoafteraspellwithOSSA.“Thewin,
allthebetterforbeingonastandardproductionbike,musthavedoneBultacoapowerofgood.”
Onthequestionofinfluences,DavecitescompetingagainstMartinLampkinandMalcolm
Rathmell,plusSammyMiller,ashelpinghimtouphisgame.

So,Dan,wereyouperchedonabikeatsixmonthsoldandneverputafootdownsince?“Hah!
No,tobehonestIwasmoreintofootballintheearlydaysuntilIgotmyroadlicencein 1995 and
thentrialsfilteredinasdadencouragedmetodothenationalswithroadwork.”Sohe’sbeen
abitofaninfluenceonyourcareerthen,anyoneelse?“Yes,SteveColleyandSteveSaunders
whenIwasstartingout.”Thestartingoutwentquitewell,astodateDanhas 130 nationalwins
andthreeS 3 championshipsandhasequalledDaveinwinningtheNorthernExpertsthree
timesinarow.ApartfromtheCub,DanhasbeensolelyGasGassince 1999 ,butbeforethathe
rodeYamahaTYandTYZ.

FATHER...


...ANDSON


“Youwantyourfrontwheelonthere,justatthesideoftheangleonthestone.”Dadimparts
someadvicetohislad.
Free download pdf