BIKE: Yamaha YZ250F

TEAM: Serco Yoshimura Yamaha

RIDER: Kirk Gibbs

MECHANIC: Michael Marty

It’s been a decade of association between Serco and Yamaha at

national motocross level and the most noticeable fruit of that merger was the pair of Australian Pro Lites MX titles, won by Cameron Taylor in 2005 and then by Jake Moss in 2007.

Serco’s entry into motorsport started way back in the day at the Thumper Nats series, with riders like Mark Avard and Mick Cotter. The decision was then to go for an all-out assault on the Aussie MX Nationals. After building a team, Serco went direct to Yamaha Australia to see what deal could be done there. They came away with the company’s 100% backing, and the task of running the official factory Lites team.

Through the years, there’s been some well-known butts on the Serco saddles – riders such as Daniel McCoy, Robbie Marshall, Adam Cini, Mitch Hoad, Brenden Harrison and Cameron Taylor. The current line-up includes Jake Moss, Ford Dale and Kirk Gibbs.

Kirk’s Serco Yoshimura Yamaha YZ250F is a direct descendant from the bike the team used in their first season in 2001. The then brand-new model ran a steel frame, before being replaced by a lighter, stiffer alloy frame when the production model got a thorough revamp in 2006.

Although not heavily modified, Kirk’s bike is the result of a stable team working on a known platform. After all, the guys at Serco have been travelling the width and breadth of Australia for the past ten years, getting the best out of the YZ250F.

SERCO’SSCREAMER

If racing improves the breed, then Serco’s ten-year tenure with the Yamaha YZ250F means that success is never very far away.

martin child ikapture

HOT-STARTA GYTR hot-start finds its way under the bars, which are equipped with Sunline levers. These items replace the standard levers that are prone to snapping in a decent crash. The change means any movement in the Sunline levers doesn’t affect the hot-start lever’s performance.

CLUTCHThe biggest change to the engine is the clutch operation – Serco runs a wet-sump kit. This allows the clutch plates to bathe in the black stuff and ‘see’ more oil than standard, meaning cooler running and less wear. The clutch itself is a Hinson unit, from basket to springs to plates.

ENGINEKirk’s engine has been built with extra power in mind. It runs a CP piston and a modified head, along with special Hotcams. The gearbox and ratios remain standard, as do the cooling lines. The radiators remain stock, although a CB4 radiator cap is used to deal with higher pressures.

CARBURETTORThe Serco YZ250F runs a Dynojet carb kit to sync the engine’s performance to the Yoshimura full titanium exhaust system that’s fitted. The carby also gets treated to a R&D fuel bowl and DNA filter, which helps it breathe easier than standard. The stock throttle tube is swapped for a faster-acting, more durable Pro Taper alloy item.

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BIKEDISSECTED

BIKE: Yamaha YZ250F

TEAM: Serco Yoshimura Yamaha

RIDER: Kirk Gibbs

MECHANIC: Michael Marty

It’s been a decade of association between Serco and Yamaha at

national motocross level and the most noticeable fruit of that merger was the pair of Australian Pro Lites MX titles, won by Cameron Taylor in 2005 and then by Jake Moss in 2007.

Serco’s entry into motorsport started way back in the day at the Thumper Nats series, with riders like Mark Avard and Mick Cotter. The decision was then to go for an all-out assault on the Aussie MX Nationals. After building a team, Serco went direct to Yamaha Australia to see what deal could be done there. They came away with the company’s 100% backing, and the task of running the official factory Lites team.

Through the years, there’s been some well-known butts on the Serco saddles – riders such as Daniel McCoy, Robbie Marshall, Adam Cini, Mitch Hoad, Brenden Harrison and Cameron Taylor. The current line-up includes Jake Moss, Ford Dale and Kirk Gibbs.

Kirk’s Serco Yoshimura Yamaha YZ250F is a direct descendant from the bike the team used in their first season in 2001. The then brand-new model ran a steel frame, before being replaced by a lighter, stiffer alloy frame when the production model got a thorough revamp in 2006.

Although not heavily modified, Kirk’s bike is the result of a stable team working on a known platform. After all, the guys at Serco have been travelling the width and breadth of Australia for the past ten years, getting the best out of the YZ250F.

SERCO’SSCREAMER

If racing improves the breed, then Serco’s ten-year tenure with the Yamaha YZ250F means that success is never very far away.

martin child ikapture

HOT-STARTA GYTR hot-start finds its way under the bars, which are equipped with Sunline levers. These items replace the standard levers that are prone to snapping in a decent crash. The change means any movement in the Sunline levers doesn’t affect the hot-start lever’s performance.

CLUTCHThe biggest change to the engine is the clutch operation – Serco runs a wet-sump kit. This allows the clutch plates to bathe in the black stuff and ‘see’ more oil than standard, meaning cooler running and less wear. The clutch itself is a Hinson unit, from basket to springs to plates.

ENGINEKirk’s engine has been built with extra power in mind. It runs a CP piston and a modified head, along with special Hotcams. The gearbox and ratios remain standard, as do the cooling lines. The radiators remain stock, although a CB4 radiator cap is used to deal with higher pressures.

CARBURETTORThe Serco YZ250F runs a Dynojet carb kit to sync the engine’s performance to the Yoshimura full titanium exhaust system that’s fitted. The carby also gets treated to a R&D fuel bowl and DNA filter, which helps it breathe easier than standard. The stock throttle tube is swapped for a faster-acting, more durable Pro Taper alloy item.

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BIKEDISSECTED

THE WENCH:MICHAEL MARTY

Michael has been with the Serco Yamaha team from day one, back in 2001. He’s seen a host of riders through the years and more than a couple of championship trophies in that time. He’s been working with the quietly spoken 22-year-old Gibbs since he joined the team in the beginning of 2009.

Is it easy to set the bike up for Kirk?MM: Kirk’s no different to the other top riders. He’s always looking for more. On the 250F, you just need to get as much horsepower as you can – the more, the

better. None of the top guys ever say they need less. Before the season started, we got Kirk to moto loads and then spent days and days on the dyno. We then gave it back to him at the track. There’s always a bit more you can find through different cams.Does Yamaha help with set-up?As we’ve been running the official Yamaha team for so long now, we have the biggest database on settings so we tend not to have to ask them these days. How does Kirk like his suspension?With Kirk, he’s been here for three years now so we pretty much know what he wants. This year we started off with settings from last year and worked from there. We’ve definitely found better

settings this year. It’s not a massive change, but it is different and he’s going with it. The bike runs a very firm fork, so it’ll never bottom-out. And the rear’s not as hard as the front.Is the engine tuned for aggression or traction off the bottom?Yes, we try to get it aggressive off the bottom so when he comes out of a corner, the power’s there and he’s got a good hit. It’s not so critical on a 450cc, but on a 250cc you always want the power there.Is there anything he finds critical? He will only run a 90-section front tyre – if I try to sneak an 80-profile tyre on, he’ll pick it on the track every time. He hates the lower profile tyre.

A Factory Effex pleated seat helps when the conditions dictate more rider grip when seated. When standing, Kirk can rely on the copious amounts of gripper

tape that covers the sideplates. The Serco Yami runs the stock super-wide footpegs, which have been production items since 2005.

WHEELSAlthough the hubs and spokes remain standard, the Serco YZ250F runs Excel rims and Pirelli tyres, with Kirk preferring the mid-hard compound at most tracks. The front brake runs an oversized GYTR disc though the rear remains bog-stock. The standard pads are retained, too.

COCKPITPro Taper triple clamps find their way onto the steering head. The offset remains standard, though Kirk runs the clamps in the frontal position for more working room in the cockpit. The Pro Taper handlebars feature a Ricky Carmichael bend and are bolted to standard risers.

GRIP

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BIKEDISSECTED