WHAT IS IT? Pro Circuit decided to bundle its 2017–2018 Honda CRF450 performance parts into a package deal. With a click of the mouse, you can build an engine that makes 6 horses more than the stock CRF450 mill.

WHAT’S IT COST? $4065.

CONTACT? (951) 738-8050 or

WHAT STANDS OUT? Here’s a list of things that stand out with the Pro Circuit Honda CRF450 engine package.

(1) Parts. The Pro Circuit package includes a high-compression JE piston (rings and wrist pin), high-lift Pro Circuit camshaft (with stiffer valve springs), CNC-machined and precision-ground titanium intake and exhaust valves (made by Del West), cylinder head porting, stiffer clutch springs, and a Ti-6 titanium exhaust pipe with a carbon fiber end cap. You can also order a separate kit that bundles just the piston, rings, wrist pin, camshaft and valve springs for $1170.

(2) Installation. MXA took a stock 2018 Honda CRF450 and ran it on the dyno. It pumped out 57.99 horsepower, which gives it the honor of producing the most peak horsepower of all the 2018 bikes. The next step was to tear the CRF450 engine down and install the Pro Circuit Performance package. Since all the components, save for the stiffer clutch springs, were top-end parts, this was a relatively easy job. Once it was buttoned up, we scheduled six test riders and three days to test and race the bike (switching back and forth with a stock 2018 CRF450). The final stage was to dyno the full-race Pro Circuit engine.

(3) Track performance. It was incredibly fast. Every test rider immediately recognized how quickly the Pro Circuit engine covered ground compared to the stocker. What was most surprising was that the same test riders claimed that it was easier to ride. The power delivery wasn’t abrupt, but instead had a long, smooth, linear feel. Plus, it continued to make more horses for 2000 rpm after the stocker went flat. The faster the MXA test riders, the more they liked the Pro Circuit engine’s ability to carry speed without any burps or glitches. Conversely, the slower the test riders (Novice or Vet), the more they favored the stock engine’s more pronounced, albeit slower, low-to-mid powerband. They didn’t have the skill to make the faster engine work..

(4) Dyno performance. Hold on to your hat! Peak horsepower on the Pro Circuit engine was 64.25 versus 57.99 on the stocker. At every step on the dyno curve, the Pro Circuit kit made more power. How much more? Two horses at 6000 rpm, 2.9 at 7000 rpm, 3.0 at 8000 rpm, 4.95 at 9000 rpm, 6.7 at 10,000 rpm and 8.8 horsepower at 11,000 rpm.

WHAT’S THE SQUAWK? Price. For the average racer, $4000 is a lot of money to spend on parts.

MXA RATING: This is a must-have engine kit for an AMA Pro, Loretta Lynn wannabe, Grand Prix privateer or filthy-rich guy. For riders in the aforementioned groups, it’s more than worth the money to have a 64-horsepower CRF450. Everyone else can get one-third the power gain for one-fourth the money by just buying the Ti-6 exhaust system.

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