FIREPOWER – Big Gun Beefs up our Honda CRF250R

When it comes time to choose a 250cc four-stroke out of the TransWorld Motocross garage, almost every test rider and editor will tend to lean towards the 2005 Honda CRF250R. Blessed with the best suspension and handling characteristics of the bunch, the CRF is also pretty potent in the power department, as well. Still, boys will be boys, and as good as the Honda is in stock condition, we couldn’t resist the urge to see how much added power we could coax out of it by sending it to one of the many four-stroke speed shops that seems to be popping up out of nowhere.
Enter Mike Young, a three-time Four-Stroke National Champion, former World Championship GP contender and factory rider for Husaberg, Husqvarna, Cagiva and Honda. When Mike suffered a career-ending injury in a motocross crash, he decided to stay involved in the sport he loved and founded Big Gun Exhaust Systems, a company that until now has been best known for its four-stroke exhaust systems. Recently, however, Young and his crew have been building some pretty impressive race motors, evidenced by the great starts enjoyed by Michael Brandes in the 125cc Nationals a couple seasons ago, and the good finishes turned in by the Bobby J’s Star Racing team in 2004.
Driven by a philosophy that the most power isn’t necessarily the best power, Big Gun strives to build high-performance four-stroke motors that not only deliver in the power department, but last a long time, as well. Once Big Gun was done with our motor, we were pleasantly surprised to hear that if we so desired, we could run it on straight super unleaded pump gas. Furthermore, the cylinder, head, valve train and crank modifications done by Big Gun are claimed to offer the same lifespan as stock components. “What good is a rocket-fast motor if you DNF every other race with it or have to rebuild it every 10 hours?” said Young. “With our engine kits, you can follow the guidelines set forth in the owner’s manual.”
Externally, the only difference in our bike’s appearance is the Big Gun EVO R-Series exhaust, but Big Gun does offer a special black external cylinder coating that is said to help dissipate heat better. Speaking of the pipe, though, the Big Gun systems underwent a complete overhaul for 2005 and now have a completely different look. From the stainless-steel header to the black-anodized muffler can and red end cap, the new design is light-years better than the previous style in the appearance department.
The first thing that pleased us about the Big Gun CRF250R was the ease with which it fired up. Unlike other modified 250cc four-strokes, the Big Gun machine fired up on the first kick and did not have that super-high compression feel at the kickstarter. After hearing Mike Young’s lectures about building a reliable, long-lasting motor, we must admit that we weren’t expecting a huge improvement in the power output. We were wrong! From idle on up, the motor has a much stronger feel with crisp, clean throttle response. The motor revs freely and quickly, but pulls smoothly through the rpm range with no traction-compromising bursts of power. Instead, the motor pulls hard in each gear, and can pull a taller gear with ease. Though the bike can be revved to the moon in each gear before shifting, it is short-shifting and riding the bike in the middle of the powerband that yields the best results. The Big Gun mods make the bike much more effective in these instances.
Our intermediate tester Mitchell Bailey was blown away by the Big Gun Honda’s new personality, and each moto he rode on the bike was no less than 30 minutes long. With the added power, the bike was easier to ride, yet not so fast that it would tire him out. On the four-stroke Bailey turned in lap times that were comparable to those on his 250cc two-stroke, but he was less fatigued and more consistent.
In a day and age where a 250cc four-stroke is fast becoming the only realistic option for 125cc class racers, it is also becoming more annd more common to see riders with built-to-the-hilt bikes that self-destruct on a regular basis. Big Gun has found a way to up the power output of the CRF250R without sacrificing its ease of starting or reliability. We’ve logged plenty of time on the CRF since we first took delivery of it, and just like it would if it were still stock, it’s running like a top.

Relieve valve pockets and squish head chamber
Port cylinder head
Set up head
Titanium valve spring set
Center guides
Oversized stainless steel valve kit
Cut piston top for new valve
Relieve crank
Bore wrist pin with 6% taper and polish
Big Gun EVO R-Series exhaust system
Call 909/948-7029 or visit

Sure, the bike is pretty, but pay extra attention to the all-new EVO-R series Big Gun Pipe. This is the finest system ever produced by Mike Young and crew.
Race Test