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3
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CARBURETOR
EXHAUST SYSTEM
RUN-IN
FUEL
Z.28R SPEC.3
PULLSTART
MA000143
USER GUIDE
HEAD CLEARANCE
LRP electronic GmbH
Wilhelm-Enssle-Str. 132-134, 73630 Remshalden, Germany
Tel.: int+49-7181-4098-0, Fax: int+49-7181-4098-30
INFO@LRP-ELECTRONIC.DE WWW.LRP-ELECTRONIC.DE
!
WARNING NOTES
ORDER NO.:
32802
3.89 PS
33.500 RPM
TECHNICAL DATA
Engine size
.28 (4.59ccm)
Exhaust
Rear
Bore
18.5mm
Stroke
17.0mm
Liner
ABC
Number of ports
8+1 (8x transfer-, 1x exhaust-port)
Crankshaft
13.0mm / SG-Shaft
Crankcase
LRP VTEC.28 Heavy Duty, black coloured
Piston
Fully CNC-machined, high-silicium alloy
Connecting Rod
Fork shaped aluminium using double bushings
Glowplug
LRP Standard style R5 (No. 35050) included
Carburetor
VTEC Competition slide carburetor, 9.0mm venturi, improved design
Power Output*
3.89 PS
Max. RPM*
33.500
Weight
450g
AIRFILTER
GLOWPLUG
*Figures may vary depending on used fuel, muffl er and tuning.
• Never leave your RC model unattended when the engine is running. If a fault should occur the
result could be a fi re in the model which could destroy anything else in the vicinity.
• All nitro engines produce gases which are very dangerous for your health; one of them is
carbonium monoxide which can lead to death! Always use your engine outdoors or in well
ventilated areas only.
• Nitro engines and their surroundings get very hot. You can seriously burn yourself when you
touch them.
• Never try to stop a running engine with your fi ngers. Pinch the fuel line or close the top of the
carburetor.
• Not suitable for children under 14 years, this engine is not a toy.
Never use regular gasoline or airplane fuel. Use fresh 2-stroke model car fuel only! We recom-
mend using our line of LRP high-quality fuels (No. 35710: 25% 1L / No. 35730: 25% 3,5L). For the
LRP Z.28R Spec.3 Pullstart engine we recommend a fuel with 25% nitro. A higher nitro content
decreases your engine’s lifetime. Therefore do never exceed 36% nitro.
A good airfi lter is very important for the life of your engine. Never run without an airfi lter, as
quick and permanent damage will result! Don’t forget to impregnate the airfi lter with a suitable
oil before usage. Carefully clean the airfi lter at least after every tenth tank. Replace the airfi lter
every 3 litres (~1 gallon) of usage.
We recommend the use of our LRP Hi-Flow 2-stage airfi lter (No. 36560) together with our LRP
Hi-Flow airfi lter oil (No. 36590).
Use only standard style glow-plugs for this engine. We recommend using our line of high-quality
LRP Platinum / Iridium glowplugs (No. 35030 - No. 35060, availabe as R3 to R6). Check them
frequently and never run with worn-out or old glow-plugs since they could damage your engine.
They turn dull when your engine was too lean and should be replaced. They should stay bright
like chrome. If the glowplugs wear out too fast, an additional 0.1mm shim between burnroom
and liner is recommended. Whenever you have trouble with the engine stalling for no reason,
replace the glow-plug fi rst!
TIP: Our LRP Team normaly uses a LRP Platinum / Iridium R5 (No. 35050) plug for the LRP
Z.28R Spec.3 Pullstart engine. Under race conditions, a LRP Platinum / Iridium R6 (No.
35060) plug is used.
Dear Customer,
thank you for your trust in this LRP product. By purchasing a LRP nitro engine, you have choosen
a high-performance and highly sophisticated product, which doesn´t make any compromise
between maximum performance and easy tuneability. We hope you enjoy your new engine.
Please read the following instructions to ensure, that your LRP Z.28R Spec.3 Pullstart engine
always works up to your full satisfaction.
Please read and understand these instructions completely before you use this product!
With operating this product, you accept the LRP warranty terms.
Never run without a pipe since this will cause excessive overheating and may damage your
engine. A good pipe has a very huge effect on the performance of a 2-stroke engine. For the LRP
Z.28R Spec.3 Pullstart, we recommend using our LRP Monstertruck Hi-Performance pipe (No.
36261) for maximum performance.
We recommend a real head clearance between piston and burnroom of about 0.75mm (0.029“)
or more, when the piston is at Top Dead Center. The real head clearance can be calculated as
follows:
Real head clearance = Thickness of head shims + 0.65mm (that‘s due to the internal
construction of the engine and the compression of the head shims, when the cooling head
is mounted)
We suggest to start with 0.20mm (0.008“) shims underneath the combustion chamber. You
may want to adjust the shims depending on nitro-content (see table) or track layout. Large
tracks may require an extra 0.10mm (0.004“) shim to reach higher topspeed and improved fuel
consumption, but this will decrease acceleration slightly.
Nitro content
16%
25%
30%
Real head clearance
0.65 / 0.025“
0.75mm / 0.029“
0.80mm / 0.031“
Head shims
0.00mm / 0.000“
0.10mm / 0.004“
0.15mm / 0.006“
The factory settings of the engine are as following and are a good starting point for you, if you
are not satisfi ed with your carburetor settings. Turn in the needles completely (Caution: Do not
overtighten them!) and loosen them the required number of turns again:
Idle screw (No.1):
Adjusts the air fl ow when carburetor is fully
closed. Turn CW for higher idle-speed and
CCW for lower idle-speed. Should be open 0.5-
1.0mm.
Mid range needle (No.2):
Adjusts the mid/low-speed fl ow rate of the fuel.
Turn CW for leaner and CCW for richer setting.
• Mid range:
3,75 turns
• Main:
3,75 turns
Main speed needle (No.3):
Adjusts the main fl ow rate of the fuel (when the throttle is opened
signifi cantly). Turn CW for leaner and CCW for richer setting.
Proper run-in of the engine is a very important step in ensuring that you get the highest perfor-
mance and lifetime of your engine. Take your time for proper run-in.
Do not use run-in benches,
but use your car for run-in.
Use the same fuel as you will be using for the life of the engine.
Special run-in fuel is not needed. If your engine doesn’t start easily you may try loosen the glow-
plug by ½-turn to decompress the engine and try again. Don’t forget to tighten the glow-plug
again once the engine started!
Procedure:
• Start the engine and set the main-needle very rich, i.e. excessive smoke coming from the
muffl er.
• Let the engine idle for 2mins fi rst to warm it up.
• Now start driving your car, it will be slow and sluggish, but this is an important step.
• Do not allow the engine to rev-up too high, run the engine at half speed on the straightaway.
• The engine should not be too cold and not too hot during run-in, 70-90°C (160-195°F) is per-
fect.
• Let the engine cool down for 15mins after each tank during the run-in period.
• We recommend doing so for 4 tanks of fuel before you start tuning your engine.
