headisclampedinposi tion andthepins
areremoved.The pi ston isthen
measuredwithanimperialmicrometer
andthe bore clearanceadded.This figure
is used to setthe cutter lengthwith a
special calibrated setting micrometer.
Onceset, th ecutterisc lampedinto the
boringbar and the cutstarted.The
Velocette hasalong cylinder borewithits
96mm stroke, andtook about10minutes
to completetheboring operation.The fit
of th episto nwas checked,thenthe final
operationwas tohonethe cylinder to
produceanice cross-hatchedfinishusing
acylinderhone.Iuse an oldDyson
vacuumtocollect thefine dustand
therwise it seems to coat
ith black dust. Mywife
mentioned theblack dust
the houseonseveral
so it’ sasimplesolution.
cylinders bored and honed
moutside andspraye dthem
-proofsatinblackpaint. The
as tofit ne wvalve guides
thevalves.Tor emove the
es Iturned upaspecial
e fromapiece of steel
ds aprotru sion on
fitnicely into the
ndanouter
ss through
erhead as
ped out.
cast iron
eat it
placed
e fro mthe
it was tapped
ecylinderhead
g asmall hammer.With
evalve guides removed, I
cleaned the
valve guide
Minibore set up tools.der hone.dtReplacing valve guides with special drift.Grinding valves and building the cylinder heads.Rear head and barrelfitted.http://www.classicmechanics.com /69