DUNCAN RACING RAPTOR 250

When it comes to 250-class sport quads, Yamaha’s Raptor 250 is as good as they get. It’s just what a serious smaller sport quad should be. The snappy, responsive engine and agile, balanced handling deliver big performance in a smaller package. If you like the Raptor 250, though, you’re probably an aggressive rider and a fast learner. In time, you’ll be looking for the next step. ATV UTV Action’s Duncan Racing International (DRI) project Raptor 250 proves that you don’t need an expensive new quad to enjoy the next level of performance.

BRINGING THE SUSPENSION UP TO SPEED

Yamaha set up the Raptor 250 with the best stock suspension you’ll find on a 250-class trail quad, but fast riders can overwork the basic, non-gas shocks, even with the stock motor. As the non-rebuildable shocks wear, they lose damping and compromise the machine’s handling. Unfortunately, Yamaha discontinued the Raptor 250R that came with adjustable, rebuildable, piggyback-reservoir gas shocks.

Duncan Racing has earned national championships because they know that handling is just as important as speed. They strongly suggest making the suspension work well before building a fast motor. DRI offers race-level components for the Raptor 250 that can be tuned for any purpose and any skill level. High-quality, rebuildable, tunable shocks are a great starting point for getting high-performance handling from machines with basic, non-rebuildable shocks.

For our project bike, we chose DRI’s Lobo II front suspension kit, which includes Roll Design A-arms and rebuildable, adjustable Elka shocks. We also chose a fully adjustable Elka Stage 5 shock for the rear. Nonadjustable, rebuildable Elka shocks are avail- able for around $600. We went with a Dominator II rear axle for its extra strength and to match the front end’s increased width, and we added a GPR Low Boy steering stabilizer to minimize jolts sent to the steering stem in rough terrain.

ADDING ENGINE AGGRESSION

Right from the dealer, the Raptor 250 engine is great for trail riders and even beginners, but as a rider’s skill increases, so will his or her hunger for more power. Fortunately, the Yamaha’s motor is mildly tuned with lots of room for more performance. Duncan Racing has a whole catalog of mods to make the Raptor faster, but for this project, we settled on one of DRI’s more affordable engine packages that provides a significant power boost without the hard-hit- ting power delivery or extra maintenance requirements of a full-race engine.

Duncan Racing’s National engine kit keeps the displacement at 250cc, so no cylinder boring or crankshaft modifications are necessary. A high-compression piston, larger intake valve, high- performance cam and head porting are the heart of the power package. Three compression levels?10:1, 12:1 and 13.5:1?are available with the kit. We went with 12:1 to get plenty of punch from the standard-bore motor. This compression level requires 110-octane race gas, but not the more expensive, super-high-octane stuff. Pump gas is fine for the 10:1 compression piston.

The $1499 kit also includes the Fat Boy 4 stainless full-exhaust system. DRI’s jet kit and the freer-flowing Pro Design Pro Flow kit for the stock carburetor to ensure the modified engine gets the fuel and air it needs for maximum power.

The beauty of the National engine kit is that you can build on it if you want even more performance. DRI has big- bore options, more radical cams and higher-compression pistons for riders who want the fastest Raptor 250 possible.

LETTING THE RAPTOR RIP

We love riding Raptor 250s, but we knew we were in for a new experience as soon as we hopped on the DRI Yamaha. Seeing the Roll Design A-arms reaching outward and hearing the raspy, high-compression engine rev when we blipped the throttle got us thinking “race quad.” Easing the clutch out and rolling on the power proved that the Raptor pulls seriously hard for a small machine. There’s a noticeable hit as the engine comes on the cam, which is fun to feel, but the motor pulls well down low and through the midrange, too, so it’s tractable and controllable for tight trails.

The suspension package changes the machine’s feel as much as the engine. Greater stability, better ride quality and massively increased bottoming resistance allowed us to push the Yamaha like a race quad?and it’s completely predictable.

Duncan Racing’s modifications for the Raptor 250 bring big-quad performance to this small sport machine. If you have a Raptor 250 and are ready for the next level in power and handling, the best “next” quad for you could be the machine you’re already riding. And if you have a tablet or smart phone, make sure to check out iTunes or Google Play to download our free app to subscribe to our digital magazine!