84 I AUGUST 2019 More old bikes online: Real-Classic.co.uk
balanceshaft multiplied thesidecoupleto
make the engine vibratelikeapaintmixer.
With thatsorted,the nextthingto
investigatewasthedrastic performance
lag below6 000 revs.Suspecting HerrBosch
mightbeonthe blink, it seemed prudentto
do an ignition scan.Withmytrustystrobe
lightplugged in,wecould see thatthe
left cylinderfiring pointwasretardedby 8
degrees.Therightsidewaslikewiseretarded
atidle butwould not advanceatall below
6000 revs.Was this HerrBosch’s fault...or
another legacyfromthemasterbodger?
Abutcher’s hookatthe pair ofBosch
triggers on the leftside settled the question.
Ourham-fistedbodger had the gaptwixtrotorandcoils setatdouble therequired
gap on onecylinder,andamonster gap on
the other.Thisisanold-style CDI system
(aka‘pointless’). Theignition advanceis
done electronically.HerrBosch in his infinite
wisdom decided thattherewould be no
ignition advancecurve.Instead itwasa
glorified switch thatinstantly switched from
fullretardtofull advanceat3000rpm.
This not-so-clever electrickerycallsforvery
precise setting of the pair of small magnetic
coils on the leftside of the engine under the
littleround inspectioncover. Witha5-thou
feeler gauge,a4mm socket headtool,and
considerablepatience, it ispossibletofixthe
gap between thecoil androtorat5thou:
notfour,not six, butfive.With this done,the
strobe lamp indicatedthatall timingwas
nowasintended,with sparks occurringat
theSandDmarks (leftandright)atidle and
shooting up the full advanceat3 000 revs.
Aquick run indicatedthatall waswell with
‘get up and go’and‘vibration, lack thereof’.
The5 00 returnedtothe benchforgeneral
cleaning–butwait,whatthe heck is this?
While applyingwaxpolishtothe petrol
tank,mybeady little eyespottedadrop
of moistureonthepetrol tank thatwould
notwipeoff.Ipokedatit with afingernail,The Formula 500 whichtook top
honoursat theBarcelona 24 hourrace,
developed from the roadgoingAlpino
twin. Riddenby Pete ‘PK’ DaviesTriumphantat the TT;SlaterBrotherstook the
Formula2teamtrophywith the 500twin in 1980