Project Bike: Cylinder Works Honda CRF270R

How a slight displacement bump and the right aftermarket parts can breathe new life into a well-seasoned, fuel-injected Honda CRF250R.

Ryan Abbatoye fires the Cylinder Works project CRF270R out of a dusty corner at Southern California's Milestone MX Park. The big bore kit can make any fuel-injected CRF250R a lot more fun to ride. PHOTOS BY SCOTT ROUSSEAU. — Ryan Abbatoye fires the Cylinder Works project CRF270R out of a dusty corner at Southern California’s Milestone MX Park. The big bore kit can make any fuel-injected CRF250R a lot more fun to ride. PHOTOS BY SCOTT ROUSSEAU.

Dirtbike tuning wizard Jay Clark loves to take already solid-performing motorcycles and make them run better, and his Cylinder Works Honda CRF270R is a perfect example. The end result is a “mature” machine that can more than keep up with its new competitors without forcing the owner to go out and buy a new bike.

Clark chose a 2010 model CRF250R because even though it is 5 years old, it stands as the gatekeeper between the current version of the machine and older ones that, dare we say it, are obsolete. The primary feature that separates the new from the old? Fuel injection.

“The Honda CRF250R was the standard for 250s for many years, and the 2010 model was the first with fuel injection,” Clark says. “We started with a 2010 CRF250R that for most of its life was very well cared for and in good shape. However, after being used as a bike rental for some Europeans for a couple of months the bike was quickly beaten down and was in need of a full restoration.”

It is kind of funny to think of a 2010 machine as in need of restoration, a term usually reserved for vintage or classic machines, but the 2010 CRF250R is a classic in its own right, and the fact is that every time an owner replaces a worn out stock part with a new stock part or an aftermarket part, that is exactly what he or she is doing–restoring the performance or durability to new, or even higher, levels. In this case, that meant going through the entire engine, chassis and suspension. Fortunately, Clark works with a lot of well-respected aftermarket parts manufacturers and thus replaces a stock part with another stock part. Nor does he like to touch a machine that he can’t improve via a more power, better handling or better suspension. So, like most of his project bikes, the CRF250R received a full-blown makeover, starting with the engine.

The engine received a complete internal makeover in the form of a new Hot Rods lower end kit and the Cylinder Works big bore kit. FMF Racing's Ti Megabomb header adds even more punch to the power curve. — The engine received a complete internal makeover in the form of a new Hot Rods lower end kit and the Cylinder Works big bore kit. FMF Racing’s Ti Megabomb header adds even more punch to the power curve.

Upon teardown, Clark quickly saw an easy opportunity to make more power than the stocker when he realized that the stock cylinder was pretty much a goner. Abused from years of hard riding and less than frequent air filter maintenance–it was, after all, a rental machine–it was ready for the scrap heap. That made Cylinder Works’ big bore kit for 2010-2015 Honda CRF250Rs a natural choice. The kit comes with a new cylinder that is a bored out to 80mm, a matching piston, rings and all the necessary gaskets and seals for a true bolt-on installation. When used in conjunction with a stock crank, the Cylinder Works kit ups the CRF’s displacement to 270cc. That’s not quite AMA-legal for the 250cc class, but it will suit open or Vet classes just fine. Best of all, with its 13.2:1 compression ratio, the engine can still be run on 91-octane pump gasoline.

But before the top-end went together, Clark started by enlisting Hot Rods Products to supply a complete bottom end kit for the engine. The Hot Rods kit also comes with everything you need, including a new crankshaft, main bearings and gaskets for the entire engine and offers an excellent alternative to stock parts. For riders seeking even more displacement, Hot Rods offers a stroker kit that adds another 9cc of displacement, but Clark felt that with the additional displacement of the Cylinder Works kit the stroker crank wasn’t necessary to achieve the power levels he was after.

The cylinder head itself also got a thorough refurbishing with the addition of a Hot Cams Stage 2 camshaft and CV4 X-2 master valve and spring kit. The Hot Cams Stage 2 cam is designed to boost mid-range and top-end albeit while sacrificing some low-end torque, which should be mitigated by the increased displacement. The CV4 X-2 valve master kit comes complete with replacement OEM-sized steel valves for the intake and exhaust sides, and it includes springs, keepers, retainers and spring locators.

The power mods didn't turn the CRF250R into beast. Rather the added mid-range snap makes it much easier to snap out of a corner or pop over a jump in a higher gear than the stocker. — The power mods didn’t turn the CRF250R into beast. Rather the added mid-range snap makes it much easier to snap out of a corner or pop over a jump in a higher gear than the stocker.

To further enhance the power of the 270cc motor via better exhaust flow, Clark went with his go-to exhaust system manufacturer, FMF Racing, which supplied a and Factory RCT Ti Muffler. The Megabomb is designed to produce more low-end to mid-range power gains while also broadening out the mid- to top-end power gains over stock–the best of of worlds. FMF describes it by claiming that it produces long header torque and short header over-rev. The TiMetal-constructed header is also claimed to reduce sound output by as much as 1.5 decibels. The Factory RCT Ti Muffler incorporates FMF’s trademark Resonance Chamber Technology, which results in a shorter overall muffler length the better centralizes chassis mass and is less susceptible to crash damage. Clark also made sure that the incoming air was as clean and unrestricted as he could make it by adding a Uni Filter two-stage air filter.

To ensure that the all that extra power made it to the ground reliably, Clark went with a complete Hinson clutch kit, which includes an inner hub/pressure plate kit, clutch basket, fiber plates, steel plates, springs and an outer cover kit. Topping four figures, the complete Hinson kit isn’t cheap, but it is of the highest quality, an it will all but ensure that the CRF wouldn’t have any clutch issues.

Builder Jay Clark made sure to use premium components throughout the machine, including a complete Tusk Off-Road wheel set (front and rear), Dunlop's tacky MX32 tires and Renthal sprockets and chain. — Builder Jay Clark made sure to use premium components throughout the machine, including a complete Tusk Off-Road wheel set (front and rear), Dunlop’s tacky MX32 tires and Renthal sprockets and chain.

Most so-called restorations happen from the ground up, and Clark took that approach with this CRF270R by making sure that its stayed connected to the ground via premium aftermarket wheels and tires. Accordingly, the bike rides on a set of Tusk Off-Road’s replacement wheels and hubs shod with Dunlop’s awesome MX32 front and rear tires. However, braking is just as important as traction, so the CRF received an upgrade in the form of Tusk Off-Road’s 270mm oversized rotor up front, along with the corresponding adaptor bracket, and a stock replacement Tusk rear disc. The Honda’s Nissin calipers are still stock, but they have been fitted with toothy Renthal brake pads for even more braking efficiency.

Factory Connection completely revalved the CRF's Showa fork and shock. The suspension mods helped to put the power to the ground while doing a great job of taming the bumps. — Factory Connection completely revalved the CRF’s Showa fork and shock. The suspension mods helped to put the power to the ground while doing a great job of taming the bumps.

The CRF’s ground attack continues with a completely revalved Showa fork and shock, thanks to the folks at Factory Connection. In case you don’t know, Factory Connection has an illustrious reputation that dates back to the company’s origins in the late 1980s, and it has proven itself as a suspension builder for motocross legends such as Bob “Hurricane” Hannah and Mike LaRocco and for such contemporary talent as GEICO Honda riders Eli Tomac and Justin Bogle. Factory Connection offers a host of parts and rebuild services intended motocross and off-road applications, so if you are looking to improve your suspension performance, they are well worth consulting to discuss your needs within your budget.

The rest of the changes to the machine are largely cosmetic, although they do add a lot of style. These include a full complement of Works Connection engine bits such as anodized front and rear brake caps, chain blocks, engine plugs, oil filler plugs, hour meter, Elite lever perches and a titanium footpeg set. Cycra Racing’s excellent-fitting body panels adorn the chassis and a Moto Seat ribbed seat cover provide better looks and better traction for the ol’ tush. Topping it all off is an Attack Graphics custom graphic set designed to Clark’s specifications. Other items include a Renthal 997 Twin Wall handlebar, replacement sprockets and dual compound grips an a Tusk Off-Road shift lever.

The CRF270R's good looks come courtesy of Cycra Racing plastic, an Attack Graphics custom graphics kit and a Moto Seat ribbed seat cover that provides more traction for the ol' rump to enhance rider control. — The CRF270R’s good looks come courtesy of Cycra Racing plastic, an Attack Graphics custom graphics kit and a Moto Seat ribbed seat cover that provides more traction for the ol’ rump to enhance rider control.

Does the bike perform as well as it looks? The short answer is yes, but it is a really short answer, as DBC test rider Ryan Abbatoye met with Clark at Southern California’s Milestone MX Park for a day of riding the Cylinder Works Honda. Right off the bat, Abbatoye noted that the 270 kit and corresponding power mods paid dividends by making the Honda much easier to ride. While it wasn’t going to be confused for a 450, the engine produced substantially more low-end and mid-range grunt, making it easier to get in and out of corners with less abuse to the clutch and also to hold a higher gear when tackling jumps and whoops. Abbatoye gave the motor two thumbs up. Likewise, the Factory Connection suspension was among the most sorted that we’ve experienced yet on one of Clark’s machines. Abbatoye noted that with just a slight change to the spring rates he would be completely happy racing the machine in a moto or a grand prix.

While hammering the clutch isn't a requirement to get the brawnier CRF270R out of a corner, Clark fitted the machine with a complete Hinson clutch kit to ensure consistent power delivery and an improved clutch feel. — While hammering the clutch isn’t a requirement to get the brawnier CRF270R out of a corner, Clark fitted the machine with a complete Hinson clutch kit to ensure consistent power delivery and an improved clutch feel.

But alas, our time with the bike was cut short by a $6 countershaft oil seal that elected to give up the ghost early in our testing session. Rather than push the issue, and with time getting away from us, we simply elected to call it a day. Eve so, we stand by our assessment that the Cylinder Works kit, combined with the FMF exhaust, is worth considering when it comes time to rebuild your worn out CRF250R. When it comes time for that next engine rebuild, just remember that there’s still no replacement for more displacement!

Cylinder Works Honda CRF270R

Rocky Mountain ATV/MC, www.rockymountainatvmc.com, 800-336-5437
All OEM parts Clutch cable, Rad Louvers and miscellaneous hardware.

Cylinder Works, www.cylinder-works.com, 515-251-4070
Big Bore 270cc cylinder kit, $529.99 (includes forged Vertex piston and cometic top-end gasket kit)

Hot Cams, www.hotcamsinc.com, 515-402-8200
Stage II camshaft, $215.99

Hot Rods, www.hotrodsproducts.com, 515-402-8100
Complete crankshaft, gaskets and main bearings, $435.97

FMF Racing, www.fmfracing.com, 310-631-4363
Factory RCT Ti Muffler,$539.99
Ti Megabomb header, $314.99

Uni Filter, www.rockymountainatvmc.com, 800-336-5437
Two-stage air filter, $26.99

Hinson Clutch Components, www.hinsonracing.com, 909-946-2942
Complete inner hub/pressure plate kit, clutch basket, fiber plates, steel plates, springs and outer cover kit, $1039.99

CV4, www.cv4.net, 800-874-122
Formed silicone coolant hoses (red), $85.99
High-pressure radiator cap, $22.99
X-2 valve master kit (steel, includes intake and valves, springs, keepers, retainers, spring locators), $384.95

Injectioneering, www.injectioneering.com, 310-953-2915
Throttle body modifications, $325.00

Tusk Off-Road, www.tuskoffroad.com, 800-336-5437
270mm oversized rotor/adaptor bracket, $119.99
Rear disc, $59.99
Front steel-braided brake line, $44.99
Rear brake pedal and clevis, $34.99
Shift lever, $17.99
Complete wheel set, $549.99

Dunlop Tire, www.dunlopmotorcycle.com, 800-845-8378
MX32 front tire, 80/100-21, $77.99
MX32 rear tire, 110/90-19, $88.99

Factory Connection, www.factoryconnection.com, 800-221-7560
Suspension rebuild and service (call for consultation and pricing)

Renthal, www.renthal.com, 877-736-8425
Brake pads, front, $34.95
Brake pads, rear, $34.95
13T front sprocket, $20.99
Rear 48T sprocket, $51.99
Works Chain, $64.99
997 Twin Wall handlebar, $95.99
Dual compound grips, $11.99

Attack Graphics, www.attackgraphics.com
Custom graphics kit, starting at $134.99

Works Connection, www.worksconnection.com, 800-895-8292
Front brake cap, $24.99
Rear Brake cap, $24.99
Chain blocks, $43.99
Engine plugs, $34.99
Oil filler plugs, $22.99
Hour meter, $34.99
Ti footpeg set, $219.99
Elite Perch, $79.95 each ($119.95 with hot-start)
Stand, $107.99

Cycra Racing, www.cycraracing.com, 740-929-0188
Powerflow complete plastic kit

Moto Seat, www.motoseat.com, 951-258-5229
Custom Cool seat cover, $64.95

Project Bike: Cylinder Works Honda CRF270R

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