Cooper Webb's Yamalube/Star Racing YZ250F

Inside this edition of Factory Bike Friday, we take a closer look at Cooper Webb's Supercross race bike.

Mechanic: Eric Gass

Cooper Webb has dominated the 250 class through two rounds of the Monster Energy AMA Supercross Series, taking come-from-behind wins in both Anaheim and in San Diego. Webb’s Yamalube/Star Racing Yamaha team has established itself as one of the top 250 teams in the paddocks, moving shoulder to shoulder with perennial standouts Monster Energy Pro Circuit and GEICO Honda.

We spoke to Webb’s factory mechanic Eric Gass in San Diego to get the scoop on Webb’s YZ250F, and according to Gass, Webb is very picky about his controls. “Even when they’re exactly the same as the last time he rode he’s still a little bit of a head case,” says Gass. “He wants to mess with them, even though it’s exactly the same as last weekend.”

Cooper Webb's Yamalube/Star Racing YZ250F and mechanic Eric Gass
Cooper Webb's Yamalube/Star Racing YZ250F and mechanic Eric GassPhoto by Shan Moore

The biggest difference between Webb’s bike and the rest of the bikes under the Star Racing canopy is Webb’s motor package. Webb likes a strong midrange, a big hit in the mid-range and then he wants the power to carry out a good ways into the higher RPMs.

Star Racing does all its own motor work in-house, and Gass says they work closely with FMF and GET to come up with motor, ignition and exhaust packages to accommodate each rider.

Anaheim One marked the team’s first race using GET’s new start assist device, though Gass says they’ve been testing it for a while.

Cooper Webb running GET start assist device
Cooper Webb's camp tries out the GET new start assist device.Photo by Shan Moore

As far as hard parts, the team changed to Neken triple clamps for 2016, and they’re also using Neken handlebars. The Neken clamps feature adjustable air chambers attached to the bar mounts, which helps dampen any major hits the rider may be taking.

According to Gass, you can vary the air pressure and that controls how much give the handlebars have. “The riders feel like it really improves the comfort level,” says Gass. “Mostly when cornering small, marbley stuff they have a bit more comfort in those corners.”

Brakes and rotors are supplied by Braking. The front is the stock 270 millimeters wave rotor. In the rear again is the stock-diameter braking disk. The calipers are stock.

The rear brake master cylinder is a factory unit, which has the window removed, and the return spring is located in the bottom. “On the bottom of the brake pedal is a return stop so if you hit a rut or something it doesn’t rip the guts out of the internal lug nut of the master cylinder.”

The gearing on Webb’s YZ is 13/50, and the team uses GYTR sprockets and chains. The chain is a lightweight 520 MXL model.

Cycra is a new sponsor for 2016, and Gass says he’s found quite a bit of improvement not only on the dyno but also on the track with the power flow shroud and air box. “With the screens on the front it also helps bring that noise a little bit down which keeps us get under the AMA sound rule,” adds Gass.

Also new for this year is the Twin Air filter.

Meanwhile, the radiators are stock, with stock capacity and stock spigots; however, they are braced to make them stronger.

Gass runs a cloth mess over the front of the radiators to keep debris from causing damage. “I got those things from Japan when we went there just a couple months ago,” says Gass. “One of the Japanese guys at Yamaha hooked me up. I think they’re actually for packaging fruit. Here in Supercross, on a non-rocky or a non-muddy race, I like to protect the radiator as much as I can, but without restricting too much airflow. So I run these light ones when the conditions are really good and then if it gets muddy or really rocky we’ll get a little bit tighter of a mesh. The tighter mesh is another sleeve that’s given to us by Twin Air. It’s just a sleeve that goes over and protects the radiators that much more.”

The swingarm and linkages are stock, but the KYB rear shock is a factory kit item.

The KYB forks are air units. “We’re back to the air fork for Supercross,” says Gass. “Cooper was running the conventional spring fork for outdoors. We might cross that bridge again when we go back to outdoors but for right now we feel that the air fork is better for supercross conditions. The tight corners and also the deep transitions, they hold up from what we can tell a bit better than the spring fork.”

The footpegs are Raptors, and Gass has taken the brace out of the middle to allow dirt and debris to fall through. Also Cooper runs his pegs five millimeters higher to compensate for his height.

YZ250F equipped with special Rekluse clutch
The clutch is a Rekluse model, however, Gass couldn’t go into too much detail. He did tell us Rekluse has come out with a new clutch for the new season.Photo by Shan Moore

The clutch is a Rekluse model, however, Gass couldn’t go into too much detail. He did tell us Rekluse has come out with a new clutch for the new season. “We’ve been working really closely with Rekluse trying to get everything dialed. It’s been a big improvement for Cooper,” says Gass. “He is usually pretty hard on the clutch; just beats up on them pretty bad. But we’ve had quite a bit of success with this new clutch package. I think it should be available to the public soon.”

Lightspeed protects the rear caliper and there’s a Lightspeed skid plate, which also adds a little bit of protection for the radiator hoses. The front disk guard is another Lightspeed item, as is the chain guide.

Yamalube/Star Racing YZ250F hub
Rear set up on Cooper's ride includes factory hubs that are machined from billet to make them even stronger for Supercross hits.Photo by Shan Moore

The hubs are factory, and they’re exactly the same as stock except they’re machined from billet, so they’re just a bit stronger. For supercross, the team runs the Excel Takasago rim, which are a bit stronger than stock and a little lighter than the A60.

“Supercross isn’t that demanding on wheels, even though you would think that whoops are pretty bad, but supercross it’s so important to downside stuff and being real smooth that they don’t go through rims as much,” says Gass. “But outdoors it’s just constant beating. We’ll switch back to the A60, which is a bit beefier, and also a little bit heavier.”

Cooper Webb's YZ250F controls set up
Eric Gass runs the ARC foldable levers on the #1w race machine.Photo by Shan Moore

Back to the controls, ARC has a really good memlon lever, foldable levers which not only fold backwards but it can bend up and bend down but still return to their original shape.

The hoses are CV4, which are the high temperature silicone hoses that help protect against heat. They’re also a bit more abrasion resistant than the stock hose. “I think they’re also lighter and they also flow a bit more volume so that also helps keep the bike cooler,” says Gass.

The Works Connection guys hooked up the Star Racing team with a really trick holeshot button. “I think it’s definitely one of the most popular ones here in our paddock,” says Gass. “Nothing too top secret about it, but we can change the height for varying conditions from track to track.

Star Racing runs Dunlop tires. Webb was running an MX32 in the front at San Diego, and an MX52 on the rear.

Webb prefers to have a full ribbed seat, which he feels helps him on the start to stay forward on the seat and keeping the bike under control.

The factory gas tank is a little bit narrower, though Gass couldn’t tell us what the volume is, but the tank itself is quite a bit narrower than stock. So that helps skinny up the cockpit and keeps the riders a bit more comfortable.

GYTR provides us with a little bit beefier ignition cover, which helps prevent breakage during an impact.