Jay Clark Enterprises stokes the fire inside the distinguished Honda CRF450X to produce one awesome off-road machine.
The Honda CRF450X has been a standard bearer in the off-road world ever since it replaced the venerable XR650R back in 2005. Utilizing much of the same technology found in Honda’s AMA National Motocross Championship-winning CRF450R motocross machine, the X-model’s 449cc Unicam cylinder head-equipped engine introduced a new level of compactness in off-road four-strokes, and its low center of gravity helped the CR450X to handle well.
Although Honda calls the CRF450X a trailbike, Team Honda put the new machine excellent use in race trim, transitioning to the X model and winning a record-setting 17th Tecate SCORE Baja 1000 for the brand in 2006. And the Johnny Campbell-led team kept right on winning, amassing an undefeated streak in the Baja 1000 on the CRF450X that was only finally stopped this year by a Kawasaki team.
With its success on the showroom floor and in the wild off-road environment of Baja, the CRF450X has proliferated greatly, recognized for its broad powerband, smooth engine character and excellent reliability. However, hard-core off-road riders and racers require more performance than the stock CRF450X is capable of, and the mods done to this Rocky Mountain ATV/MC, Cylinder Works, FMF Racing Honda CRF478X deliver just that.
This particular machine belongs to off-road tuning guru Jay Clark of Jay Clark Enterprises. In case you missed them, our Hot Cams 2014 Suzuki RM-Z250 and project Vertex Kawasaki KX450F are typical examples of Clark’s handiwork. Since we want to showcase great off-road machines as much as we do motocross bikes (we are, after all, DirtBikes.com), showing off this off-road warrior was natural fit.
If you know Clark’s work, then you know that he goes all-out to build the most-trick bikes he can in order to showcase parts and pieces for the companies he represents, but what makes the CRF450X a great candidate for the full-house treatment is that it has seen minimal changes in its nine-year production run. That means there are a lot of good used machines out there that can be purchased for a fraction of the cost of a new one, thus leaving the builder with a lot more dinero to spend on aftermarket hardware.
This particular bike, a 2005 model, was purchased off of Craigslist for a mere $2300. It was in excellent shape, making it the perfect candidate for conversion into an extreme trail/off-road racebike. Best of all, despite its engine modifications, this CRF478X still runs on happily on 91 octane pump gasoline. One more thing: Every major product for this project can be obtained directly from its respective manufacturer, or you can just do a one-stop shop by making a call to Rocky Mountain ATV/MC. It doesn’t get much easier than that!
Engine/Clutch
The stock, carbureted CRF450X is no fire breather, but it can be woken up with the right pieces. In this case, that included bumping up the engine’s displacement with a Cylinder Works big bore kit. The $649.95 kit comes with everything needed for the conversion, including +3mm oversize cylinder, a Vertex piston, rings, wrist pin, clips and gaskets. It adds another 29cc of displacement, and as we’ve all been taught, there is no replacement for displacement when it comes to making more power. If you want to go even further, though, you can use a Hot Rods #4170 connecting rod to pump up the displacement to a full 500cc.
If you think of the engine as just a fuel-fired air pump, we didn’t want to just make our pump bigger, we also wanted to get the air in and out more efficiently, so Clark also went with a cam change, opting for a Hot Cams Stage 1 camshaft. At $269.95, it’s an inexpensive way to increase bottom-end and midrange power and also improve throttle response. The Hot Cam retains the stock auto-decompression mechanism to ensure easy starting, and it also doesn’t require heavier, aftermarket valve springs; the stockers can be used with the Stage 1 cam.
More power and greater efficiency can also be gained through a different exhaust system—in fact, it’s usually the first place to start. Clark went with proven parts in the form of an FMF Racing Megabomb header and Power Core 4 Hex aluminum muffler. The Power Core 4 is designed for closed-course use only, but FMF Racing also offers its Q4 Hex S/A, complete with a U.S. Forestry Service-approved spark arrestor. At 5.5 lbs., the Q4 is only three tenths of a pound heavier than the Power Core 4, but it is legal for use on public land. There is a slight difference in price between the two units as well. The Power Core 4 retails for $319.99, and the Q4 retails for $379.99. The Megabomb header is available in titanium for $349.99 or stainless steel for $279.99.
That’s about it for the heavy motor mods, although if you want to shave a couple lbs. off your stock CRF450X, you can install Applied Racing’s CRF450X Emissions Block-Off Kit, which allows you to remove the smog pump. However, be advised that doing so is a closed-course-only modification. The kit comes with all the necessary hardware to handle the conversion, and it only costs $39.55. Lastly, Clark opted for a Uni Filter two-stage air filter to keep the incoming air clean, and CV4’s red coolant hoses and high-pressure radiator cap to jazz up the looks of the bike.
Clutch performance is critical on an off-road machine, especially when the going gets tight and gnarly. That’s the wrong time to find out that a stock clutch setup can’t hack the abuse, so Clark avoided the issue by sticking with more tried and true parts from Hinson. The CRF478X gets a full complement of Hinson goodies, including its FSC clutch plate and spring kit ($199.95), and its billet clutch cover ($169.99).
Suspension
The stock CRF450X suspension works reasonably well in casual to moderate of-road chop, but since this CRF478X was slated for off-road and Grand Prix racing, Clark wanted to beef up the fork and shock.
To do that, he once again enlisted the services of Mike Battista at MB1 Suspension in Corona, California. Battista, a former Team Honda Showa suspension technician, started MB1 in 2004 to offer his suspension expertise to the public, and MB1 has earned a solid reputation among customers with Showa-suspended motorcycles.
MB1 is admittedly a motocross suspension shop, but that doesn’t mean that it has no experience in the off-road world. Communication is the key to any successful relationship and, as the MB1 suspension tech we spoke to confirmed, “Our customers can never give us too much information.”
In this case, Clark worked with MB1 to revalve and then carefully rebuild each fork leg as well as the rear shock. The goal was to develop a ride that was slightly plusher than the typical motocross suspension setup while still retaining the ability to soak up high-G hits. MB1 changed the shims and pistons and then performed a careful rebuild of each component. MB1 offers its customers up to 90 days to test their revalved suspension, and if it isn’t to their liking, they can return it for a one-time adjustment free of charge. MB1 added that it prides itself on getting it right on the first try.
Accessories
Clark works with several top-shelf companies when it comes time to adding accessories, and the project CRF478X is no different. Cycra Racing is one such go-to company, and Clark went with a Cycra Lite front fender to sharpen the 478’s looks. For added rider hand protection Clark added Cycra’s Probend CRM handguards to the bike’s Renthal 997 Twin Wall handlebar. The guards feature a trademark Probend shape that gives them plenty of area to accommodate hands and levers. The guards are made of tough, injection-molded plastic.
In addition to the 997 Twin Wall handlebar, this project bike features a host of Renthal goodies, including Renthal RC-1 Works sintered metal brake pads, which were designed specifically for motocross and off-road racing. The RC-1’s sintered metal compound is made from nine different materials that Renthal says increases performance while reducing brake fade. The pads feature a ceramic heat shield backing designed to resist brake fluid overheating. To lower the final gearing, Clark opted for a stock Renthal countershaft sprocket but a 3-tooth larger rear sprocket. The cogs are connected via a Renthal O-ring Works Chain.
Many of the trick pieces on the CRF478X bear the Works Connection name, including such items as the Elite lever perches, engine and oil plugs, and the brake reservoir caps, but Works Connection’s full-coverage skid plate may be the most important of the bunch. Constructed of aircraft-grade .160-gauge, heavy-duty aluminum construction and TIG welded for strength as well as beauty, the skid plate offers a narrow glide path while providing ample coverage to protect the frame rails and engine cases. It features access holes for easy oil changes, and it comes with all the necessary mounting hardware, including CNC-machined mounting brackets. The skid plate installs in minutes, and at $199.95 its cheap insurance against expensive frame or engine damage from the demons that lurk below.
We are big fans of Trail Tech’s Voyager off-road computer already, and Clark showed us another cool Trail Tech component by putting it on this bike, the Trail Tech X2 headlight. Tailored specifically for racing, the X2 headlight is designed to outperform a typical stock headlight. Its HID beam offers a wide spread and strong projection for riding from dusk to dawn, and it looks more radical than the stock headlight to boot.
The rolling stock comes straight from Tusk Off-Road, with the CRF478X wearing a complete Impact wheel kit, with nice-looking, red-anodized hubs. A Tusk Off-Road Typhoon 270mm oversized floating rotor kit is located up front, while a Typhoon stainless steel rear brake rotor rides out back. Dunlop was chosen for its excellent off-road rubber, with the bike sporting the company’s excellent AT81 front and rear treads. Lastly, Clark topped off the CRF478X with a Moto Seat ribbed seat cover, the grippy double-stitched material adding to the bike’s “works” looks.
Riding Impression
DirtBikes.com test pilot Ryan Abbatoye is even better at off-road riding than he is at motocross, and if you’ve ever seen the “RAD” one burn up a moto track then you know that’s saying something. Remember that this is the same guy who finished third with teammate Kendall Norman in the 2013 Baja 500. He also hails from Ridgecrest, California, a veritable breeding ground for fast desert dudes—and ladies, too. So when we asked him to swing a leg over the CRF478X and gives us his impressions, we knew he’d be right at home.
First off, if you didn’t know any better, you would think that the CRF478X is basically a stocker as you listen to it idle. Sure, the noise is amplified a little—and in the most bitchin’ way—by the FMF exhaust system, but the larger bore and Hot Cams Stage 1 bumpstick don’t hint at the extra power the bike is now making. After a few trips through the gears, the cat was quickly out of the bag.
Abbatoye stopped short of characterizing the CRF478X as providing all-out, Baja-winning race power, and that’s no surprise as we’d imagine that the factory bikes he has raced down south have quite a few more bucks invested in their motor development. They also don’t run on pump gasoline, either. Abbatoye was nevertheless happy with the power of the big bore kit and cam, noting that it feels substantially stronger than the stock CRF450X without being unruly. The extra low-end grunt and mid-range power made the bike easy, fun and fast.
Suspension-wise, the MB1 valving was in the ballpark, although once again Abbatoye would have liked to be able to take the time to dial-it in for himself rather than try to base his impressions off settings made for a rider who is 30 lbs. heavier. Overall, though, he noted that it is still more controlled than the stock suspension at high speed but could use just a little more plushness for smaller hits and jittery bumps. Again, he expressed that with a little time to set it up, he could be more than happy with the MB1 fork and shock.
When all is said and done, however, Clark and the companies listed here collaborated to produce one heck of a fantastic off-road machine. Granted, you don’t need to go as far as Clark did to improve your CRF450X, but this one shows just how far one can be taken, and it also goes to show the potential of the stocker in the first place.
Rocky Mountain ATV/MC, Cylinder Works, FMF Honda CRF478X
Cylinder Works www.cylinder-works.com 515-251-4070
3mm Big bore Cylinder Kit 478cc, $649.95
Includes Forged Vertex Piston and Cometic Top-End gasket kit
Hot Cams www.hotcamsinc.com 515-402-8200
Stage-One Camshaft, $269.95
FMF Racing www.fmfracing.com 310-631-4363
Powercore 4 Muffler, $319.99
Megabomb header, $349.99 (titanium)/$274.99 (stainless steel)
Applied Racing www.appliedrace.com 800-853-0555
Emissions Block-Off Kit, $39.55
Uni Filter www.rockymountainatvmc.com 800-336-5437
Two-stage Air Filter, $30.95
CV4 www.cv4.net 800-874-1223
Formed Silicone Coolant hoses (Red), $139.62
High pressure radiator cap, $22.73
Cycra Racing www.cycraracing.com 740-929-0188
Cycra Lite Front Fender, $39.95
Probend CRM Handguards, $82.95
Renthal www.renthal.com 877-736-8425
Stock front sprocket, $20.99
Rear 48T sprocket, $69.95
O-ring Works chain, $85.95
997 Twin Wall handlebar, $199.95
Dual Series grips, $15.95
RC-1 brake pads, $34.95 (front)/$34.95 (rear)
Dunlop Tire www.dunlopmotorcycle.com 800-845-8378
AT81 front 90/90-21, $71.99
AT81 rear 120/90-18, $74.99
DeCal Works www.decalmx.com 815-784-4000
Semi-Custom Graphics kit w/ pre-printed number plates backgrounds, $269.90
Moto Seat www.motoseat.com 951-258-5229
Ribbed Stripe seat cover, $64.95
IMS www.imsproducts.com 800-237-9906
Pro Series Foot Pegs, $96
Works Connection www.worksconnection.com 800-895-8292
Elite Perch, $79.95 each
Front brake cap, $27.50
Rear Brake cap, $24.95
Axle blocks, $49.95
Engine plug kit, $39.95
Oil fill plug, $24.95
Hour meter, $39.95
Hour meter mount, $14.95
Skid plate, $199.95
Hinson Clutch Components www.hinsonracing.com, 909-946-2942
FSC clutch plate & spring kit, $199.99
Billetproof clutch cover, $169.99
Tusk Off-Road www.rockymountainatvmc.com, 800-336-5437
Typhoon 270mm oversized floating rotor kit, $149.99
Typhoon stainless steel rear brake rotor, $99.99
Impact complete front/rear wheel kit, $729.99
Rocky Mountain ATV/MC www.rockymountainatvmc.com 800-336-5437
All OEM parts Clutch cable, Rad Louvers and miscellaneous hardware.
Pro Moto Billet www.promotobillet.com 866-466-4762
Kick-It Stand, $159.95
Trail Tech www.trailtech.net 360-687-4530
X2 headlight, $324.95
MB1 www.mb1suspension.com 951-371-5045
Fork Revalve, $180
Fork Oil, $24.99/qt.
Shock Revalve, $180
Shock Oil, $24.99
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