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Mod Squad | 2018 Husqvarna FC 270 Big Bore


Mod-Squad | 2018 Husqvarna FC250 Big Bore

How shall we address this bike build? Let’s just say that for a vet-class racer or a casual rider, a 250cc four-stroke motocross bike is easily the most-fun bike choice available. While a full-sized 450 has more power than most of us can take full advantage of, a 250 can be ridden harder, for longer, with greater control. However, getting a good start on a smaller bike is often a challenging proposition when racing against a field full of 450s; so what’s a small-bike-loving vet to do?

Through the years, we’ve found that simply pumping a few more cubic centimeters into a 250s engine can work wonders off the line and make things much more even when it comes to racing. When it comes to high-level amateur racing in the 250 class, we’re certain that several big-bore 250s are out there too, as it is simply more cost-effective and more reliable to “cheat” with a big bore. Do we condone that? No, but we understand. Haha!

Our buddy Jay Clark got his hands on a used 2018 Husqvarna FC 250 for a good price, and wanted to do some small local REM Races on it and also have some fun in the hills on it. Cylinder Works makes a 3mm larger big bore kit for the Husky and KTM 250s that bumps the bike’s displacement to 269cc. The kit comes complete with a cylinder, a Vertex Piston, and a gasket kit, and it utilizes the bike’s stock head and valve train. Jamie Ellis is a wizard when it comes to coaxing more power out of engines, so he cut the valve seats to match the new larger cylinder and piston, and also ported the head to provide maximum power. Then, he added a Vortex ignition that he loaded with 10 different map settings to complete the engine itself. An FMF Racing Powercore 4.1 system was added, and this rounded out the engine package to Jay’s vet dream bike.

When it comes to the suspension on a Husqvarna or KTM, the weak link in the package is the WP AER48 air fork. Technical Touch makes a KTM conversion kit for the WP fork that essentially removes all of the WP internals and replaces them with KYB parts. Factory Connection did the install and set the fork and shock up for Clark’s weight and speed while they were at it. 

Jay wanted the bike to stand out so he went with a black and flo yellow color scheme. Different, for sure, but he went all in and had the frame powder coated flo yellow by Chris Johnson at San Diego Powder Coating. The rad thing about SDPC is that Johnson himself is a professional motocross racer, and he knows the ins and outs of powerdercoating a motorcycle frame. Furthermore, their work is impeccable, and it is the best place on the West Coast to get your frame powdercoated.

Power from the 49-horsepower 269cc engine is put to the ground with a Supersprox Chain and sprocket. We’ve got plenty of experience with the Supersprox Gold MX Race Chain, which is a moto-friendly O-ring style. Most people associate O-ring chains with lots of power-robbing drag, but we ran them on two of our test bikes throughout the year and have nothing but good things to say about them. Not only is the supposed “power loss” detectable, but the chains barely stretch and hardly require any tightening. 

Scar Racing produces some beautiful titanium footpegs that are lighter than stock and offer a wicked amount of grip. We have to wonder if the brand name was influenced by the result of a slipped peg? On a serious note, the pegs offer plenty of support thanks to their wide platform, and no slipping happens with their super-sharp teeth!

Our Pro test rider Mike Sleeter has plenty of experience with the standard 2018 Husqvarna FC 250 as he was a lead test rider in the development of the 2018 KTM 250 SX-F, which shares much of the same technology with the Husky. While Sleeter and the rest of the SML Test Crew have been busy testing new 2020 models, he came away both surprised and impressed with the effectiveness of Jay Clark’s project 270. 

“I’m usually skeptical of big-bore bikes because they always seem to produce the power in the wrong place,” said Sleeter. “But this bike built by Jamie Ellis is a real runner! Jamie is a master of building and setting up engines, and I was really impressed. It runs just about as good as a 350.”

Watch the video above to see the rest of Sleeter’s feedback!


Cylinder Works



3mm Big bore Cylinder Kit 269cc  
Includes Forged Vertex Piston and Top-End gasket kit
Twisted Development 
Vortex X-10 ECU & mapping
Head Porting to match the big bore cylinder (valve seats cut) 
FMF Racing  
Full Ti Megabomb with RCT 4.1 Muffler                               
Factory Connection
Suspension rebuild and service
Instalation of KYB Conversion kit from Technical Touch 
Technical Touch 
KYB Conversion kit for AER48 forks 
Faster USA 
Complete Wheel set 
Galfer USA 
Oversized Rotor/Adaptor Bracket
Rotor rear  
Brake pads front and rear
Rear Sprocket 51T  
Front Sprocket 14T 
Gold MX Race Chain G520-MXT-L-120
Uni Filter     
Two-Stage air filter                     
Hinson Clutch Components     
Full Clutch kit – Basket, Inner hub, Pressure plate and Fibers, steels and springs clutch kit  w/cover.  
Pivot Works   
Steering stem bearing kit       
Linkage bearings 
Radiator straightening and bracing           
All Balls 
Throttle cable
603 Fat bars  
Tacky grips 
Dunlop Tire   
MX53 front  80/100-21
MX33 rear  110/90-19

Works Connection    

Brake Caps 
Works Stand II
Brake Rotating bar mount
Engine plugs 
Axle Blocks 
Holeshot Device
UFO Plastic 
Full plastic kit in Black 
Mud Flap   
San Diego Powder Coating                 
Sandblasting, powder with super-durable clear, and “race prep masking’  
DeCal Works   
Semi-Custom Graphics kit                    
Pre printed number plates backgrounds 
TM Design Works 
Rear Chain block 
Moto Seat                               
Custom Cool seat cover
Motion Pro
Grip Glue
Titan throttle tube 
Fasst Co 
Rear Brake Return Spring
Pro Factory Hoses
Radiator hoses in white 
Titanium Footpegs
VP Fuel 
T4 or U4.4 Fuel (does run on pump fuel as well)  
Husqvarna OEM Parts  
New Black Airbox piece 
KTM Black frame guards  —taller than Husky ones 
Two-Stroke Air Filter Cage 
Donn Maeda

Donn Maeda is a 30-year veteran in moto-journalism, having worked at Cycle News and Dirt Rider before launching MXracer Magazine and TransWorld Motocross Magazine. Maeda is the Editor-In-Chief at Swapmoto Live and you can catch him on a dirt bike or in the saddle of a mountain bike on most days.

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