SportMaxx Manual Part 1 - Horizon Hobby

Traxxas CorporationCorporate Headquarters1100 Klein RoadPlano, Texas 75074Phone: 972-265-8000Toll-free 1-888-TRAXXASTraxxas U.K.P.O. Box 1128Winterbourne, Bristol BS17-2SHEnglandPhone: 44.117.956.1002Internetwww.Traxxas.comwww.MaxxTrucks.comE-mail: support@Traxxas.comEntire contents ©2003 Traxxas Corporation. Traxxas, SportMaxx,TRX 2.5, TQ-3, Top Fuel, EZ-Start, Ready-To-Race and ProGraphixare trademarks or registered trademarks of Traxxas Corporation.Other brand names and marks are the property of theirrespective holders and are used only for purposes ofidentification. No part of this manual may be reproduced ordistributed in print or electronic media without the expresswritten permission of Traxxas.0208022

IntroductionThank you for purchasing a Traxxas SportMaxx nitro monstertruck. Traxxas engineers focused on the essentials ofperformance by putting plenty of horsepower in a lighterweight, more agile monster. The new wide Maxx suspensionfeatures multiple shock mounting adjustments, adjustable rideheight, and powerful 4-wheel disk braking. The transmission islean and mean with extremely low rotational mass for fasterthrottle response, and quicker acceleration. Rear wheel drivefurther improves the horsepower-to-weight ratio for excitingracing action. The SportMaxx is a serious, performance-mindedmachine for a new breed of driving enthusiast. Down the road,SportMaxx is completely upgradeable to full T-Maxxspecification with optional kits for reverse, 4-wheel drive, andtwo-speed operation. A three-channel radio system is alreadyinstalled to make upgrades easy. Plus nothing has moreaccessories and customization options than a TraxxasMaxx truck!The SportMaxx’s new TRX 2.5 Racing Engine is the mostpowerful engine of its size ever available in a Ready-To-Runtruck. Two years of engineering development and advanceddesign, along with thousands of hours of testing, puts the TRX2.5 in a class by itself. Each part of the TRX 2.5 - from the air filteron the slide carburetor, to the tip on the dyno-tuned exhaustsystem - has been carefully engineered to provide maximumpower over the broadest RPM range.Traxxas was the first with standard on-board electric starting.The new second generation EZ-Start has evolved into anincredibly advanced and reliable starting solution, featuringthermal protection for the motor and built-in diagnostics tomonitor the condition of the glow plug.Obviously, there’s much going on between the wheels of yourSportMaxx. In this manual, we’ll take you step-by-step throughall necessary set-up, break-in, tuning, and operating procedures.Even if you are an experienced R/C enthusiast, it isimportant for you to read and follow the procedures in thismanual. Pay particular attention to the fuel requirementsand break-in procedures. The advanced design of the TRX2.5 racing engine does not follow old-fashioned thinkingregarding fuel and break-in procedures.4 Before You Proceed5 Safety Precautions6 Tools, Suppliesand RequiredEquipment7 Anatomy of theSportMaxx8 Quick Start: GettingUp to Speed9 Gluing the Tires10 DecoratingYour SportMaxx11 The Traxxas TQ-3Radio System21 The TRX 2.5racing engine37 Driving theSportMaxx38 AdjustingYour SportMaxx41 Trouble ShootingYour SportMaxx43 Maintainingand StoringYour SportMaxx45 Index3

Before You ProceedCarefully read and follow all instructions in this and anyaccompanying materials to prevent serious damage to yourSportMaxx. Failure to follow these instructions will beconsidered abuse and/or neglect.Before running your SportMaxx, look over this entire manual,and examine the truck carefully. If for some reason you decidethe SportMaxx is not what you wanted, then do not continueany further. Your hobby dealer absolutely cannot accept aSportMaxx for return or exchange after it has been run.Warnings, helpful hints, and cross-referencesThroughout this manual, you’ll notice warnings and helpfulhints, identified by the icons below. Be sure to read them!An important warning about personal safety or avoidingdamage to your SportMaxx and related components.SupportIf you have any questions about your SportMaxx or itsoperation, call the Traxxas Technical Support line toll-free at:1-888-TRAXXAS (1-888-872-9927)Technical support is available Monday through Friday from 8:30am to 9:00pm central time. Technical assistance is also availableat www.Traxxas.com. You may also e-mail customer supportwith your question at support@Traxxas.com. Join thousands ofTraxxas R/C enthusiasts in our online community atwww.ReadyToRun.orgTraxxas offers a full-service, on-site repair facility to handle anyof your Traxxas service needs. Maintenance and replacementparts may be purchased directly from Traxxas, or you can saveshipping and handling costs by purchasing them from yourlocal hobby dealer.Special advice from Traxxas to make things easier andmore fun.Refers you to a page with a related topic.4

Safety PrecautionsAll of us at Traxxas want you to safely enjoy your newSportMaxx. Operate your SportMaxx sensibly and with care, andit will be exciting, safe, and fun for you and those around you.Failure to operate your SportMaxx in a safe and responsiblemanner may result in property damage and serious injury. Theprecautions outlined in this manual should be strictly followedto help ensure safe operation. You alone must see that theinstructions are followed and the precautions are adhered to.Important Points to RememberR/C fuel is dangerous and highly poisonous. Always follow alldirections and precautions printed on the fuel container.▼ ▼ ▼ ▼ ▼ ▼R/C fuel, especially when in a fuel dispensing bottle, maylook like a cool drink to a child. Keep all fuel out of the reachof children at all times. Do not place fuel containers on theground where children can get to them while you aredriving.R/C fuel is flammable. Never allow smoking, sparks, heat orflame in the presence of fuel or fuel vapors.The engine and exhaust system may become extremely hotduring use. Be careful not to touch the parts, especially whenrefueling or stopping the engine.Prolonged exposure to the engine exhaust can be harmful.Avoid breathing the engine exhaust. Always run yourSportMaxx outdoors, in a well-ventilated area. Never run theengine indoors.Don’t operate your SportMaxx at night, or anytime your line ofsight to the model may be obstructed or impaired in any way.▼ ▼ ▼ ▼Never operate your SportMaxx in crowds of people or busypedestrian areas. The SportMaxx is large and fast, and maycause injury to those unaware of its presence.Because the SportMaxx is controlled by radio, it is subject toradio interference from many sources beyond your control.Since radio interference can cause momentary loss ofcontrol, always allow a safety margin in all directions aroundyour model to prevent collisions.The engine can be loud. If the noise makes youuncomfortable, wear ear protection. Be considerate of yourneighbors by not running your model early in the morningor late in the evening.Most importantly, use good common sense at all times.All instructionsand precautionsoutlined in thismanual should be strictlyfollowed to ensure safeoperation of yourSportMaxx.The SportMaxx isnot intended foruse by those under 16years of age without thesupervision of aresponsible andknowledgeable adult.5

For more info onbatteries, see Usethe Right Batterieson page 13.A peak-detectingcharger isrecommended forbest performance andlongest battery life. Formore information, see Usethe Right Charger on page30.Tools, Supplies, and Required EquipmentYour SportMaxx comes with a set of specialty metric tools. You’llneed to purchase other items, available from your hobby dealer,to operate and maintain your model.Supplied ToolsYour SportMaxx comes with these specialty metric tools:TRAXXAS1.5mm hex wrench2.0mm hex wrenchGlow plug (universal) wrenchTurnbuckle wrenchesU-Joint wrenchFilter oil (for the foam air filter)see page 27 for detailsFuelTraxxas Top Fuel10% quart - #5010 • 20% quart - #502010% gallon - #5060 • 20% gallon- #5070Fuel dispensing bottle (Traxxas part #5001)Other Required Tools and SuppliesThin, hobby-quality cyanoacrylateinstant tire glue (often called CA glue)Safety glasses#2 Phillips screwdriver#1 Phillips screwdriverBatteries12 AA alkaline batteries for the radio system7.2-volt NiCad battery pack for theEZ-Start starting systemNiCad battery chargerSmall flat-blade screwdriver (1/8 inch blade)Hobby knifeAfter-run oil (WD-40) to protectthe engine from corrosion6

Anatomy of the SportMaxxPressure LineEZ-StartMotorFuel LineFuel TankLidFuelTankSlipperClutchSpurGearBatteryBoxChassisOn/OffSwitchSteeringServoSuspensionArm (upper)Bumper(Front)ShockTowerEZ-StartPlugSkid Plate(front)BumperMountCross-braceBodyMountHalf ShaftAirFilterPipeHangerAntennaMountTransmissionBulkheadShock(Oil Damper)PipeReceiverBoxHeaderEnginesee pg. 20 for detailsAccess Plugfor Receiver CrystalThrottle/BrakeServoTurnbuckle7

The Quick StartGuide is notintended toreplace the full operatinginstructions available inthis manual. Please readthis entire manual forcomplete instructionson the proper use andmaintenance ofyour SportMaxx.Quick Start: Getting up to SpeedThe following guide is an overview of theprocedures for getting your SportMaxx running,from opening the box to breaking in and tuning your engine.Refer to the pages indicated for details on each step. Look for theQuick Start logo on the bottom corners of Quick Start pages.1. Charge the battery pack • See sidebar, page 30The EZ-Start requires a fully charged 7.2-voltbattery pack (not included).2. Get the right fuel • See page 26Use Traxxas Top Fuel or consult with Traxxasbefore using other fuels.3. Glue the tires • See page 9Glue the tires to the rims to prevent the rimsfrom spinning inside the tires.4. Install the antenna • See page 15Install the antenna mast in the SportMaxx.5. Decal and Install the body • See page 10You will need to use the body during the break-inprocess so it’s best to decal it before you use it onthe truck.6. Install batteries in the transmitter • See page 13The SportMaxx requires 8 AA alkaline or rechargeablebatteries for the transmitter.7. Install batteries in the model • See page 14The SportMaxx requires 4 AA alkaline or rechargeablebatteries for the receiver.8. Install the EZ-Start battery • See page 30Install and connect the 7.2-volt battery pack inthe EZ-Start controller.9. Turn on the radio system • See page 18Make a habit of turning the transmitter on first, and off last.10. Check servo operation • See page 19Make sure the throttle and steering servos are workingcorrectly.11. Range test the radio system • See page 20Follow this procedure to make sure your radio systemworks properly at a distance and that there is nointerference from outside sources.12. Fill the fuel tank • See page 26Use your fuel-dispensing bottle to fill the tank.13. Connect the EZ-Start to the model • See page 31Learn the proper way to use the EZ-Start electric startingsystem14. Start the engine • See page 32Learn to use the correct starting procedure for your TRX 2.5.15. Break-in your engine • See page 32Follow the break-in instructions exactly to ensure the bestperforming,longest-lasting engine.16. Tune your engine • See page 34Learn how to set the fuel mixture needles for optimumengine performance.17. Drive your SportMaxx • See page 37Driving tips and adjustments for your SportMaxx18. Maintaining your SportMaxx • See page 43Follow these critical steps to maintain the performanceof your SportMaxx and keep it in excellent runningcondition.8

Gluing The TiresThe tires on your SportMaxx must be glued to the rims using CAtire glue to prevent the rims from spinning inside the tires. Youcan glue the tires without removing the wheels from the truck.For clarity, these instructions show the process with the wheelsremoved.1. Remove a wheel from theSportMaxx using the larger(8mm) end of the glow plug(universal) wrench.HubAxle Pin4. Reinstall the wheels, makingsure none of the axle pinshave fallen out from behindthe hex hubs.Always wear safetyglasses to preventglue from splatteringinto your eyes.The acetone infingernail polishremover willremove excess glue fromyour fingers.2. Use your thumb to push theside of the tire away from therim. Place one or two drops ofCA glue into the opening andrelease the tire. Capillaryaction will draw the gluearound the bead of the tire.For best resultswhile gluing, cleanthe bead of the tiresand the grooves of thewheels with denaturedalcohol before applyingglue. This removes any moldrelease agent residue fromthe tires and wheels,providing a better bond.3. Repeat step two at four or five points around the rim, until thetire is completely secured to the rim. Turn the rim over andrepeat the process for the inside of the rim/tire. Repeat for theother 3 wheels.9

Decorating Your SportMaxxApplying The DecalsThe ProGraphix paintedbody is covered with aprotective film for shipping.You must remove this filmbefore applying any decals.To remove the film, lift acorner of the film andcarefully pull it off the bodyin one continuous piece.Your SportMaxx decals aredie-cut for easy removal. Usea hobby knife to lift thecorner of a decal and lift itfrom the backing.Carefully position the decalover the desired locationand press one side on thebody. Pull the decal tightand use a finger to graduallysmooth out any air bubblesas you apply the decal.Look at the photos on the box for typical decal placement.10

The Traxxas TQ-3 Radio SystemYour SportMaxx (model 5110) is equipped with the TQ-3 RadioSystem. The TQ-3 is a 3-channel system that provides high-poweroutput up to a quarter mile and control for up to three servos.The SportMaxx makes use of two channels for throttle/brake andsteering. The third channel is reserved for future upgrades withoptional reverse module and third shifting servo (availableseparately).AntennaThrottle TrimThrottle Neutral AdjustSteering WheelSportMaxx WiringDiagramAntennaReceiverOn/OffSwitchBlackNegativeRedPositive4-CellBattery HolderYour SportMaxx canbe outfitted with fullreversing capabilityby installing the optionalreverse module (soldseparately).Steering Trim3rd ChannelSwitch*Channel 3 *Channel 2Channel 1BatteryChannel 1Steering ServoThrottle TriggerChannel 2Throttle ServoCH.3CH.2CH.1ServoReversingSwitchesPower SwitchBattery CompartmentPower Indicator*Reserved for optional shift servo and reversing module11

Learn terms relatedto the TRX 2.5racing enginebeginning on page 23.The Traxxas TQ-3 Radio SystemRadio System TerminologyPlease take a moment to familiarize yourself with these radiosystemterms. They will be used throughout this manual.Channel - The 27 MHz frequency band is divided into 6channels so that up to six models can be operatedsimultaneously. Each channel is referred to by its flag color andchannel number, as shown below.Channel Frequency Band Flag Color Traxxas Part No.1 26.995 Brown 20312 27.045 Red 20323 27.095 Orange 20334 27.145 Yellow 20345 27.195 Green 20356 27.255 Blue 2036Clearing your frequency - A routine, verbal check to make surenobody else in your area is operating on the same channel.Always clear your frequency by calling out your channelnumber before operating your model. Wait or move toanother area if your channel is already being used.Crystal (X-tal) - The plug-in device that determines whichchannel the radio system will operate on. For each channel,there are two crystals, one for the receiver and one for thetransmitter. Of those two crystals, the one marked with thelower number (.455 MHz lower) must be inserted into thereceiver.Frequency band - The radio frequency used by the transmitterto send signals to your SportMaxx. All Traxxas RTR modelsoperate on a 27 MHz frequency band.Neutral position - The standing position that the servos seekwhen the transmitter controls are at the neutral setting.NiCad - Refers to rechargeable, nickel-cadmium batteries. Themost economical choice, since they may be recharged up to500 times.Receiver - The radio unit inside your SportMaxx that receivessignals from the transmitter and relays them to the servos.Servos - Small motor units in your SportMaxx that operate thethrottle and steering mechanisms.Three-channel radio system - The TQ-3 radio system,consisting of the receiver, the transmitter, and the servos. Thesystem uses three channels: one to operate the throttle, one tooperate the steering, and a third channel which is reserved forshifting with optional reverse module (sold separately).Transmitter - The hand-held radio unit that sends throttle andsteering instructions to your SportMaxx.Trim - The fine-tuning adjustment of the neutral position of theservos, made by turning the throttle and steering trim knobson the face of the transmitter.12

The Traxxas TQ-3 Radio SystemInstalling Transmitter BatteriesYour TQ-3 transmitter uses 8 AA batteries. The batterycompartment is located at the base of the transmitter.CH.3CH.2CH.1Use the Right BatteriesYour transmitter and receiveruse AA batteries. Use newalkaline batteries, orrechargeable batteries such asNiCad or Ni-MH (nickel-metalhydride) batteries in yourtransmitter and receiver. Makesure rechargeable batteries arefully charged according to themanufacturer’s instructions.1. Remove the battery compartment door by pressing thetab and lifting the door up.2. Install the batteries in the correct orientation as indicatedin the battery compartment.3. Reinstall the battery door and snap it closed.4. Turn on the transmitter and check the power indicator fora solid red light.If the power indicator light flashes, then the transmitterbatteries are weak, discharged or possibly installed incorrectly.Replace with new or freshly charged batteries. The powerindicator light does not indicate the charge level of thereceiver batteries in the model.If you use rechargeablebatteries in your transmitter, beaware that when they begin tolose their charge, they losepower much more quickly thanregular alkaline batteries.Caution: Discontinuerunning your SportMaxx atthe first sign of weakbatteries (flashing red light)to avoid losing control.If the power indicatordoesn’t light red, checkthe polarity of thebatteries. Check rechargeablebatteries for a full charge.13

The Traxxas TQ-3 Radio SystemDirect the batterywires through theslot in the batterycover. If the wires are notproperly routed, they maybecome broken or shorted,causing radio systemfailure and loss of control.Installing Receiver BatteriesThe radio receiver in your SportMaxx uses 4 AA batteries. Thebattery holder for the receiver batteries is located underneath thebattery cover. The battery cover can be identified by the on/offswitch.1. Remove the battery cover by removing the two 3x10mmroundhead self-tapping screws from the cover.2. Remove the battery holder and install 4 AA alkaline batteries.Make careful note of the battery polarity by comparingagainst the diagrams in the battery holder.If you use rechargeablebatteries in your receiver,be aware that when theybegin to lose their charge,they lose power much morequickly than regularalkaline batteries. Signs ofweak receiver batteriesinclude sluggish steeringresponse and shortenedradio range. Caution:Discontinue running yourSportMaxx at the first signof weak batteries to avoidlosing control.On/OffSwitch4-cellbatteryholderIf the radio systemdoesn’t appear towork when thetransmitter and receiverswitches are turned on,check for correct batteryinstallation.143. Insert the battery holder into the battery cover.4. Reinstall the battery cover and secure with the screws(see sidebar!).

Setting Up the AntennaYou must install the antenna mast (tube) before you operateyour SportMaxx. You’ll find the plastic antenna tube and tip inthe bag with your manuals and documentation.1. Locate the black antenna wire that exits the receiver cover.The SportMaxx receiver cover is mounted on the top of thechassis, near the front.2. Pull the wire straight with your fingers and then insert theend of the wire into one end of the antenna tube. Push thewire all the way through the antenna tube.3. Pull the remaining wire through the antenna tube, and theninsert the base of the antenna tube into the molded post ontop of the receiver cover.4. Fold the remaining antenna wire over the top of the tubeand secure it with the antenna tip.5. On the transmitter, always fully extend the telescopingantenna when running your SportMaxx. Make a habitof holding the transmitter so that the antenna pointsstraight up.Antenna TipAntenna TubeThe Traxxas TQ-3 Radio SystemSpray a little windowcleaner on theantenna wire tomake it easier to pushthrough the antenna tube.Don’t shorten thelength of theantenna wire. Itslength is tuned to thefrequency band; cutting itcould severely shorten theradio system’s range.Don’t push thetransmitter antennadown from the top.Pull it down from thebottom, one segment at atime, to prevent binding andkinking the antenna mast.15

The Traxxas TQ-3 Radio SystemTQ-3 Radio System ControlsOther TQ-3 Radio System AdjustmentsIn addition to the electronic throttle and steering trim controls,your radio system features throttle neutral adjustment andservo reversing switches.LEFTRIGHTThrottle Neutral AdjustmentThe throttle neutral adjustment is located on the transmitterface and controls the forward/brake travel of the throttletrigger. Change the adjustment by pressing the button andsliding it to the desired position. There are two settingsavailable:50/50: Allows equal travel for both acceleration and braking.70/30: Allows more throttle travel (70%) and lessbrake travel (30%).50/50 is the required setting for the SportMaxx withthe TRX 2.5 racing engine.▼ ▼ACCELERATEBRAKENEUTRALCH.1CH.216CH.3Electronic Throttle TrimThe electronic throttle trim located on the face of thetransmitter adjusts the neutral (center) point of the throttleservo when the servo is at rest. This control has been preset foryou at the factory. If necessary, adjust the control so that thecarburetor is at idle, and the brakes are not applied (the model

The Traxxas TQ-3 Radio Systemwill roll freely). Do not use the throttle trim to raise or lower theengine idle speed. Make the idle speed adjustment on thecarburetor.Electronic Steering TrimThe electronic steering trim located on the face of thetransmitter adjusts the neutral (center) point of the steeringservo when the servo is at rest. Adjust this control to make themodel drive straight with no steering input at the wheel.Servo Reversing SwitchesThe servo reversing switches are located on the front of thetransmitter, next to the on/off switch. Moving a switch reversesthe direction of the corresponding servo.Each switch corresponds to a channel, as shown below. Forexample, if you turn the steering wheel to the right and yourfront wheels turn left, you would move the channel 1 switch tocorrect the servo direction. It may be necessary to adjust thecorresponding trim control after moving a switch.Channel Servo1 Steering2 Throttle and braking3 (Available for future use.)CH.3CH.2CH.117

Remember, alwaysturn the TQ-3transmitter on firstand off last to avoiddamage to yourSportMaxx.The Traxxas TQ-3 Radio SystemTQ-3 Radio System RulesEach time you prepare to run yourSportMaxx, you must clear yourfrequency to be sure no one else in thearea is using the same channel as you.▼ ▼ ▼There are six possible channels,numbered 1 through 6. Each isrepresented by a color. Look at thecrystal plugged into the back of yourtransmitter to determine which channelyour truck is assigned to.Channel 1BrownChannel 2RedChannel 3OrangeChannel 4YellowChannel 5GreenChannel 6BlueAlways turn your TQ-3 transmitter on first and off last. Thisprocedure will help to prevent your SportMaxx fromreceiving stray signals from another transmitter, or othersource, and running out of control.Always have the transmitter and receiver turned on beforeyou start the engine. Never turn the radio system off whilethe engine is running. The on/off switch in the model onlyturns the receiver on and off. It does not turn off the engine.▼Always use new or freshly charged batteries for the radiosystem. Weak batteries will limit the range of the radio signalbetween the receiver and the transmitter. Loss of the radiosignal can cause you to lose control of your SportMaxx.1 2 3CH.3CH.2CH.118

Using the TQ-3 Radio SystemThe TQ-3 Radio System was pre-adjusted at the factory. Theadjustment should be checked, before running the model, incase of movement during shipping. Here’s how:1. Fully extend the chrome antenna mast on the transmitterand turn the switch on. The red indicator light on thetransmitter should be solid red (not flashing).2. Turn on the receiver switch in the model. The switch islocated on the battery cover.3. Position the SportMaxx so that its front wheels are off theground.4. Turn the steering wheel on the transmitter back and forthand check for rapid operation of the steering servo. Also,check that the steering mechanism is not loose or binding. Ifthe steering operates slowly, check for weak receiverbatteries.5. When looking down at model, the front wheels should bepointing straight ahead. If the wheels are turned slightly tothe left or right, slowly adjust the steering trim control on thetransmitter until they are pointing straight ahead.The Traxxas TQ-3 Radio System6. Operate the throttle trigger on the transmitter and check forrapid operation of the throttle servo. When the throttletrigger is pulled back, the carburetor should open. When thethrottle trigger is pushed all the way forward, the brakeshould lock.7. Once adjustments are made, turn off the receiver on yourSportMaxx, followed by the handheld transmitter.ThrottleBrakeThrottle/BrakeServoWhen the engineis running, don’tuse the throttletrim on the transmitter toadjust the engine idlespeed. Instead, use theidle speed adjustment onthe carburetor.Because yourSportMaxxfeatures zeroscrub-radiussuspensionand wide tires, thesteering servo will notfully turn the front wheelswhen the vehicle is notmoving.0°0°SteeringServoSportMaxx ServoOperation19

The Traxxas TQ-3 Radio SystemDon’t attempt tooperate yourSportMaxx if thereare any problems with yourradio system or radiointerference at yourlocation.Range-Testing the TQ-3 Radio SystemBefore each running session with your SportMaxx, you shouldrange-test your radio system to ensure that it operates properly.1. Turn on the radio system and check its operation as describedin the previous section (Using Your Radio System, pages 17- 19).2. Have friend hold the model with the engine off.3. Make sure your transmitter antenna is fully extended, and thenwalk away from the model with the transmitter until you reachthe farthest distance you plan to operate the model.4. Operate the controls on the transmitter once again to be surethat the model responds correctly.5. Do not attempt to operate the model if there is any problemwith the radio system or any external interference with yourradio signal at your location.20

The TRX 2.5 Racing EngineIntroductionThere’s nothing like the TRX 2.5 racing engine in your newSportMaxx. The TRX 2.5 racing engine is vastly superior totypical R/C engines and belongs in the category of specialtyhigh-performance racing engines. It’s the result of years offocused engineering development, and thousands of hours ofcontrolled testing and rigorous real-world running. It offersunprecedented power and performance that turns ready-to-runinto Ready-To-Race ® .The TRX 2.5 racing engine takes a total-system approach. Eachpart of the engine, from the air filter to the exhaust tip, iscarefully engineered to work in harmony with other enginecomponents. Each part complements the next, to extractmaximum power. The TRX 2.5 is designed to be tolerant ofvariations in tuning, and to run successfully through a widerange of variable atmospheric conditions, such as changes intemperature, humidity, and altitude.The TRX 2.5 is manufactured to exacting tolerances and requiresa specially-designed break-in procedure to accomplish the finalprecision fitting of the internal engine components. It is veryimportant that you follow the new break-in procedure as closelyas possible to achieve the best performance and longest lifefrom your TRX 2.5 racing engine. Old style break-in procedures,such as simply running the engine with a very rich fuel mixturefor the first 4 tanks of fuel, will not achieve the best results.Follow the steps in this manual.Traxxas stronglydiscourageschanging ormodifying any part of theTRX 2.5 racing engine. Oldtech tips and tricks thatmay have boosted thepower of other enginescould seriously diminish theperformance of the TRX 2.5.There’s more advancedthinking, development andtesting in the stock parts ofyour TRX 2.5 than in manyaftermarket manufacturer’sso-called performanceparts. The TRX 2.5 is alreadythe most powerful enginesin its class and simply willnot benefit from average,low-tech, aftermarket bolton performance items.A routine maintenance schedule is also required to keep theTRX 2.5 in top running condition. Cleaning the air filter aftereach hour of running is particularly important. Also it isextremely important to perform after-run maintenance on theengine to prevent corrosion from building up on the internalengine components (see page 44).21

The TRX 2.5 Racing EngineTRX 2.5 IllustratedAirFilterIdle SpeedScrewHead ProtectorHead (Cylinder head)EZ-StartDrive UnitHigh-Speed NeedleFuel IntakeAir IntakeCarburetorFlywheelClutchBellEZ-StartMotorCrankshaftGlow PlugWireGroundWireThrottleArmLow-SpeedNeedleEZ-StartPlugNegativeWireEngineMountCrankcaseEZ-StartControllerPositiveWireExhaustTipPressureLineFuel LinePipe22Fuel Tank