High speed Needle Valve
The.high.speed.needle.valve.is.preset.from.the.factory.for.the.initial.starting.
procedure..
do not make adjustments to it at
this time.
.The.high.speed.needle.valve.is.used.
to.meter.the.air/fuel.mixture.at.full.throttle..Turn.
the.needle.valve.clockwise.to.lean.the.mixture.or.
turn.the.needle.valve.counterclockwise.to.richen.
the.mixture.
Check to ensure that the high speed needle valve is set at 3 full turns
out from the closed position for the break-in process.
low speed Needle Valve
The.low.speed.needle.valve.is.preset.from.the.factory.for.the.initial.starting.
procedure..
do not make adjustments to it at
this time.
.The.low.speed.needle.valve.meters.
the.air/fuel.mixture.at.idle.and.during.transition.
from.idle.to.full.throttle..Turn.the.needle.valve.
clockwise.to.lean.the.mixture.or.turn.the.needle.
valve.counterclockwise.to.richen.the.mixture..The.
low.speed.needle.valve.is.preset.from.the.factory,.but.minor.adjustments.may.
need.to.be.made.to.suit.your.application:.fuel.used,.glow.plug.and.environment.
all.contribute.to.the.setting.
do not adjust the low speed needle valve until afTER the engine has
been broken in.
There.may.come.a.time.when.you.get.the.needle.valve.settings.out.of.spec,.
resulting.in.poor.engine.performance.or.not.even.being.able.to.start.the.engine.
at.all..If.this.occurs,.reset.the.high.speed,.mid.range.and.low.speed.needle.
valves.to.their.factory.settings.as.described.below:
Resetting the High speed Needle Valve
l
Gently.turn.the.high.speed.needle.valve.clockwise.until.it.bottoms.out.(fully.
closed)..
do not force it or you may damage the carburettor
.
l
Turn.the.high.speed.needle.valve.counterclockwise.(open).
3 full turns
.
Resetting the Mid Range Needle Valve
l
The mid range needle valve should be flush with the carburettor housing.
Resetting the low speed Needle Valve
l
Open.the.carburettor.barrel.completely.
l
While holding the carburettor barrel open with your fingers, use a flat blade
screwdriver.to.gently.turn.the.low.speed.needle.valve.clockwise.until.it.
bottoms.out.(fully.closed)..
do not force it or you may damage the
carburettor
..From.this.point,.turn.the.low.speed.needle.valve.counterclockwise.
3 full turns
..
PRO TIP
When the engine is new, it can sometimes be difficult to turn
over.and.may.cause.your.starter.box.to.slip..A.trick.to.help.this.is.to.loosen.
the.glow.plug.slightly,.start.the.engine,.then.remove.the.glow.starter.and.
retighten.the.glow.plug..This.effectively.lessens.the.engine's.compression,.
making.it.easier.to.turn.over.the.engine.
The.SH..21.XB.PRO.Competition.Off-Road.engine.features.a.ceramic.piston.
(XB-1.features.an.aluminium.piston).and.a.chrome-plated.brass.sleeve.(liner)..The.
cylinder.sleeve.(liner).is.tapered.at.the.top,.causing.resistance.when.the.piston.
moves.through.the.top.of.the.stroke..This.is.normal..When.the.engine.heats.up.to.
operating.temperature,.this.resistance.will.decrease.and.the.proper.clearance.will.
be.achieved..The.break-in.procedure.will.guide.you.through.the.steps.necessary.
to.properly.break.in.your.new.engine..Please.follow.the.steps.closely.
Breaking in an engine with a ceramic piston is the same as breaking in a standard
aBC engine, except that the break-in period may take a little longer.
do NoT oMiT THE ENgiNE BREaK-iN PRoCEduRE!
The break-in process allows the engine parts to perfectly fit to each other
and.properly.protect.each.part.from.premature.wear..
The engine should
be broken in using a good quality R/C car fuel that contains no more
than 20% nitromethane and 10%~14% oil content.
q
. Follow.the.Starting.Procedure.to.start.the.engine.
q
. Once.the.engine.starts,.keep.the.glow.starter.attached.to.the.glow.plug.
and.let.the.engine.run.for.about.10.seconds.without.giving.it.throttle..This.
will.allow.the.engine.to.warm.up..At.this.point.the.engine.should.be.running.
very."rich".and.the.engine.will.also.sound.like.it's.running.rough.
To. make. sure. that. you're. not. leaning. out. the. engine. too.
much.and.overheating.it.during.break-in.and.under.normal.
use,.we.suggest.using.a.temp.gun.to.monitor.the.engine's.
temperature.
during break-in, engine temperature should not exceed
280ºf (138ºC). The optimum engine operating temperature
is 230º~260ºf (110º~127ºC). The minimum engine operating
temperature is 180ºf (82ºC).
Turn.Clockwise
to.Lean
Turn
Counterclockwise
to.Richen
Turn.Clockwise
to.Lean
Turn
Counterclockwise
to.Richen
Page 3
HIGH SPEED, MID RANGE AND LOW SPEED NEEDLE VALVES
RESETTING THE NEEDLE VALVES TO THE FACTORY SETTINGS
BREAK-IN PROCEDURE
Mid Range Needle Valve
The.mid.range.needle.valve.is.preset.from.the.factory.for.the.initial.starting.procedure.
and normal use, and is used fine-tune the air/fuel
mid. range. mixture.. Turn. the. needle. valve.
clockwise.to.lean.the.mixture.or.turn.the.needle.
valve.counterclockwise.to.richen.the.mixture..
do
not make adjustments to the mid range need
valve until after tuning both the high and low
speed needle valves, and until afTER the engine has been broken in.
q
. If.your.vehicle's.fuel.tank.has.a.primer.pump,.press.this.pump.several.
times.to.draw.fuel.to.the.carburettor..When.the.fuel.reaches.the.carburettor,.
stop.priming..Over-priming.the.engine.can.cause.the.engine.to."hydro-lock".
Never try to start the engine if it is hydro-locked. This could cause serious
damage to the engine.
q
. If.your.fuel.tank.does.not.have.a.primer.pump,.fuel.will.be.drawn.into.the.
carburettor.when.you.turn.the.engine's.crankshaft.using.your.starter.box.
q
. The.engine.is.started.by.connecting.the.power.to.the.glow.plug.then.turning.
the.crankshaft,.using.your.starter.box,.until.the.engine.starts..Once.the.engine.
has.started,.your.vehicle.can.be.removed.from.the.starter.box.
IMPORTANT
..We.recommend.using.a.1/8th.scale.starting.box.to.start.
your.engine..We.strongly.suggest.reading.the.operating.instructions.that.
are.included.with.your.starter.box.before.attempting.to.start.the.engine..This.
will.ensure.that.you.are.familiar.with.how.to.use.your.starter.box.properly,.
so.you.don't.damage.your.starter.box.or.your.engine.
STARTING PROCEDURE
Turn.Clockwise
to.Lean
Turn
Counterclockwise
to.Richen
