I’ve had the opportunity to build some really cool quads over the past two decades. Twenty years in the industry, with eight working as a magazine editor, has afforded me the luxury of working hand in hand with some of the best companies in our little world. We’ve featured many of my previous race bike builds over the years, but this one is a different kind of special. We have recently taken on the WORCS races as a family, and it was finally time to build a full-on race bike for my son.
To say I might have gotten into this build with mini-dad intensity would be an understatement. The plan all started to come together over dinner with my good friend, Allen Knowles of CT Racing. We were bench racing about how many 10-year-olds would be pumped just to sit on a machine like Yamaha’s Raptor 250, much less race one at the WORCS level.
The rest of our conversation transcended into how much better we could make this already cool little racer. As it turned out, CT Racing already knew how to extract a ton of power from the 250. In fact, they had been building them for years. We decided that CT would handle all things power, and I would call upon a handful of other industry associates for the rest of the top-of-the-line components.
We tore the motor out and dropped it off with CT Racing for the full treatment, and at the same time we opted to completely tear the Raptor down for a Teixeira Tech gusset kit and powdercoating by Madera Brothers in Bakersfield, California. Madera Brothers not only provides a super-quick turnaround on powdercoating, but they also have a great fab shop in-house as well.
MONSTER MOTOR IN THREE FLAVORS
CT Racing has been developing the Raptor 250 motor since its introduction back in 2009. They currently offer three different motor combinations. An AMA 300cc XC kit that consists of their top-end package, along with a stroker crank, and a custom JE 78mm big-bore piston offering a high-torque package. The AMA 300cc MX package utilizes the stock crank and custom 80mm JE piston kit, along with CT’s top-end package offering a higher-revving MX motor. Then, as we chose here, the 250cc International package is a 250cc standard bore-and-stroke package used worldwide, including WORCS. This package includes a choice of JE pistons from 11.0:1, 12.0:1 and 13.0:1, depending on fuel choices.
CT Racing CNC-ports the head and uses their Newnen CNC contour-valve machine to tie the porting into a five angle radius valve job, just as many NASCAR teams are currently doing. CT removes the valve guides and installs shorter guides, as the stock ones are way too long and impede flow. CT uses a +1mm intake valve, with the overlap on the cam CT Racing designed.
There is not enough clearance to run +1mm valves on both sides. CT uses a camshaft developed by their staff and ground to that spec by Web Camshafts. CT has many different performance piston configurations all made by JE Pistons.
One of the cool things you’ll find on our ride is the first-ever quick-change clutch cover from CT Racing. To change the clutch on the Raptor is a long, slow process. If you have a clutch issue at the track, you could miss a race fooling around trying to slip in a fresh clutch. CT will have these for sale in anodized colors available by the time you read this. Check out their website for details and colors. While on the subject of clutches, CT Racing has developed their own clutch stack for the Raptor, offering wider plates than stock and giving more surface area to handle the added horsepower of this little hot rod.
UPPING THE INTAKE & EXHAUST
CT Racing has done a lot of development on the intake tract. CT offers a 33mm FCR for the National 300 kit, and, for the XC and 250cc package, they run a CT-built 30mm FCR. To build this carb, they start with a generic 28mm Keihen FCR carb. They bore the carb to 30mm, have a spigot made to adapt the inlet side to the Raptor manifold, and modify the body of the carb, adding a float bowl venting system. They also modify the float bowl to clear the starter motor, and modify the air boot for added horsepower.
The carb is then jetted and is available with a cable for thumb or twist. A Pro Design Pro Flow filter can be found in the air box; we use the foam element for WORCS and other off-road races and a K&N type for sand application. With the Pro Design, the aluminum retainer bolts into the airbox and stays there. Then the filter is removed and installed with a clamp. This is the best system for retaining a filter. With the Pro Flow, the ring is the same so you can go back and forth between K&N and foam filters easily.
CT Racing offers their own highoutput exhaust system for the Raptor 250, CT has been known to win many pipe shootouts over the years, and certainly this pipe is geared to the horsepower their package offers. It’s a big head-pipe model and stepped up several times heading to the silencer can. It comes with a turndown end cap, but is available with the disc system for predominately running in spark-arrestorrequired areas. The CT pipes are very easy to re-pack, using Allen screws to assemble over rivets used in many systems.
With power developed and the higher rpm the motor will work efficiently to, a higher-rpm CDI box is needed. CT uses the Dynatek CDI box. The Dynatek offers a higher rev limit, along with a better ignition curve, developing more horsepower.
We’ve got lots of horsepower out of the little Raptor, so what we needed to make it a competitive race quad was handling. We went with Aren’s Extended long-travel A-arm kit. Aren’s is not a Johnny-come-lately slap out some A-arms. They have been building ATV frames and race components since the Honda 250R days. Aren’s has a robotics welder offering very highquality welding with perfect heat control throughout the weld. The +3-inch, longtravel A-arms connect to the spindles using Frap Italian-made ball joints.
These are the best ball joints on the market and an excellent choice for your Raptor. We connected the Aren’s arms to a set of Elka Stage 5 shocks. The Elka Stage 5s offer a multi-spring setup, allowing ride-height adjustment, along with high- and low-speed compression and adjustable rebound damping. The Elkas are the top-of-the-line shocks used by a lot of top pros. They offer a plush ride through the small stuff, and yet you can jump this thing off of a bridge and get asoft landing. We used the Elka Stage 5 in the rear as well, ensuring the rear end works as well as the front end.
The Raptor 250 makes a light, fast, agile race machine, and as we added parts to it we were very cognizant of the weight and not wanting to add any more than necessary. We chose the Dura Blue X33 pin-drive axle. The X33 is a hollow axle with pins to lock the hubs in place as opposed to splines.
Being a completely hollow axle with a large-diameter shaft, it is both light and strong. It is a 2+2 design, so it can be run full AMA-legal width of 50 inches or narrowed to 4 inches for XC or low-traction situations. This axle is significantly wider and lighter than the stock axle.
CONTROLLING THE BEAST
We opted for the impact-absorbing Fasst Company Flexx handlebar system that actually absorbs bumps and impacts before they can reach your hands and arms, wearing you out. We also installed a Precision-RP stabilizer in this same effort to create the best possible ride, one that won’t prematurely wear out our young rider. With the most comfortable handlebars ever made, we had to go all out with the controls as well. We opted for the unbreakable ASV folding levers and Motion Pro cables and Vortex twist throttle. The ASV levers feature a three-year warranty against breakage, and they feel like a million bucks. Our Motion Pro throttle kit came complete with cable, throttle and even new grips. All these go-fast parts and stuff let it rip faster through rough terrain, so we needed to work on slowing it down. We went to Streamline for some help. Streamline not only offers the quality stainless steel lines, but they come in cosmetically correct colors. The stainless lines firm up the brakes, saving energy on the track, that makes them worth doing, and we needed extended lines to match up with the A-arms. Streamline also offers excellent brake pads that offer more stopping power than stockers, as do the rotors as well.
We opted for DWT’s racer-in-abox wheel package with 9-inch rear beadlocks and a 10×5-inch rolled-lip fronts. We chose to wrap them in the DWT XC V2, as they are six-ply-tough, but they come in 1-inch narrower sizes than most other WORCS-type tires. The XC V2s are 20×10-inch rears and 21x6x10 fronts available in soft, medium, and hard compounds for any terrain. As the Raptor would be used primarily for WORCS racing, we installed the Tire Blocks run-flat system inside the DWT tires. This foam-wedge run-flat system is the easiest way to avoid flat-related failures, DNFs or lost time. Our Tire Blocks are a special compound that they had been developing just for this type of endurance racing.
Finding quality nerf bars, footpegs, and aluminum protection for the Raptor used to be quite a chore, but not anymore. HMF Racing has stepped up their production with the IQ Defense line, and they have a really solid nerf/ heel guard and footpeg combo for the little Raptor. We installed them in black with a matching bumper and grab bar. All of these modifications turn a fun play bike into a factory-level race machine that any kid would dream about riding.
Arens Bros. Suspension—call John at