User guide

ThunderTech Products - 6655-A Amberton Drive - Elkridge, MD - 21075 - PH: [phone] - Fax: [phone]
Fo R s&s ‘g’
ca R b u R e t o R s
GENERAL INSTRUCTIONS
Fo R s&s ‘g’
ca R b u R e t o R s
READ INSTRUCTIONS FIRST!
Please read all instructions
fully and carefully before
proceeding.
Drilled, tapped and spot faced for
fuel delivery tube.
Body and the air correction spacer
installed, nipple facing front of
bike.
Drilled, tapped, spot faced for
adjustable air bleed jet.
External bowl vent machined in
body.
Ifyoudonothavefacilitiesavailable
to properly install this module,
professional installation is available
from Zipper’s.  High volume shops
maywanttoinvestinourThunderJet
installation xture (shown in the
photos,p/n713-910).
ThissecurelyholdstheCarbbody
andoatbowlatthecorrectpositions
for machining.  For use with a mill
when installing ThunderJets in all
S&SmodelE/G/B/Dcarbs.
1.Loosenthedrainnutandremove
your oat bowl from the Carb.
Remove emulsion tube with main
jet from Carb body and remove the
acceleratorpumprod,rubberbellows
and discharge o-ring.  Looking into
Carb throat, turn Carb counter-
clockwise at approximately an 11
degreeangleandclampinvice.
2.The location for drilling,tapping
andspotfacingthefueltubeholeis
.950” from the air cleaner mounting
surface;use the upperleftcornerof
the “T” in the word “SHORTY” for
locatingtheotheraxis.Drillaletter“I”
hole,tap5/16-24.Using1/2”endmill,
counterboreholeuntilyoumaintaina
3/16”(.187)wallthickness(photo1).
4. Locate air bleed passage plug
above S&S nameplate on throttle
spoolsideofCarb.ClampCarbbody
at approximately a 45 degree angle.
Centera5/16”endmillovertheplug
and spot face lightly to atten and
align. Use a center drill to start and
thendrilltheplugwitha#19drillbitand
tap5mm x .8mm forair bleed (photo
4). Install airbleed jet (same type jet
usedinThunderJet).Jetsizesrange
from 130-170 for most applications
(seechart).
3. Remove jam nuts (no longer
needed).  Install the air correction
spacer(smallopeningout),o-ringand
ThunderJetbodyontoCarb.Fuelline
nippleshouldpointtofrontofbikeand
slightly toward the air lter for hose
routing(photo3).Trimsmallopening
sideofaircorrectionspacer,ifneeded,
toachieveahandtightlocation1/6ofa
turnfrompermanentlocationandnish
tightening with wrench. (.006” trim =
1/6 turn).  DO NOT OVERTIGHTEN
BODY OR FUEL TUBE BREAKAGE
WILL RESULT!!
5.ClampCarbinviseupsidedown.
Locateoriginal internal airbleedhole
(photo5)tobeblockedoff. (’04 and
earlier)Carefullydrillthispassagewith
a #21 (.159”) drill bit until you break
intocrosspassageinCarbbody.Tap
hole with a 10-32 tap, blow passage
outwithcompressedair,thenplugwith
supplied10-32slottedscrew. (’05 and
later)Thesecarbscomewithamain
jet style air bleed jet; remove the jet
and plug the hole with the supplied
5/16-24setscrew.
Adjustable Air Bleed
Original air bleed passage tapped
for block-off screw.
Fuel delivery tube installed.
Original Air Bleed Blocking
6. We have found additional
performance and increased fuel
pressure stability in the oatbowl by
relocating and modifying the oat
bowl vent passage. Clamp body
upside down at a 45 degree angle.
Remove the existing 5/16” bowl vent
plug(photo6). Using a small center
drillorwiggler,locatethecenterofthe
holewhereplugwasremoved.Mark
aspot 7/16”fromthecasting surface
whereventplugwasremoved,toward
top of Carb.  Using a small center
drill, break through to existing vent
passage.  Finish hole using a 5/16”
2-uteendmillatthisangle.Cut only
deep enough to enter existing vent
cross drill!
In extreme high velocity applications,
we recommend plugging the original
ventpassageattheaircleanerbacking
plate surface (tap opening 5/16-24).
Use the 5/16”-24 plug removed from
the vent passageto plug the original
opening,asextremeairowcancreate
avacuumthatmaydrawfuelthrough
(Optional) Bowl Vent
Relocation
3.
 Install the fuel delivery tube
from the inside of the Carb throat
out(photo2).Using(2)¼”-28jam
nuts, double-nut the fuel delivery
tubeoutsideoftheCarbthroatand
carefullylocktubeintoCarbthroat
until all or most of the air bleed
segmentisexposed.
Do n o T o v e R T i g h T e n b o D y
o R f u e l T u b e b R e a k a g e
w i l l R e s u l T !
Remove bowl vent passage
plug.
Bowl drilled, tapped and spot
faced for bowl tting
Bowl tting installed
7.Removeoatfrombowl.Setbowl
at a 20 degree angle on sine plate.
Drilla#3holebetweenbowldrainplug
andacceleratorpumphousingandtap
with¼”-28tap.Spotfaceholecenter
(kiss)justenoughtogiveaatsurface
for o-ring to seal against (photo 8).
Install fuel nipple and o-ring, secure
insidebowlwithlockwasherandnut
provided (photo 9).  Make sure this
device does not interfere with oat
action.
8. ThoroughlycleanCarb,checklow
speed and main jet sizes for engine
compatibility (see tuning tips), re-
assembleCarbandinstallfuellinewith
clampsprovided.Fuelhoseisrouted
tofrontofbike.Seetuninginstruction
pageforjettinginstructions.
Float Bowl
9. ReaD Tuning
insTRuCTions
the vent and uncontrollably richen
themixture.Installtheplug just deep
enoughtobeslightlybelowtheairlter
mounting surface, and use Loctite. If
youchoosenottodothismodication,
at least remove the vent plug and
discardit.