GASGAS EX300 PROJECT: BEHIND THE BUILD

Dicks Racing has been building high-end off-road racing machines for decades. A racer himself, Dick Wilk pounded the hostile desert around Las Vegas and taught himself the art of making his machine handle better and perform stronger through focused suspension and motor modifications. His most recent project started with the GasGas EX300 two-stroke TPI machine.

His original thoughts about the machine weren’t exactly positive. “If I’m gonna ride a 300, it better run really well.” He was clearly disappointed after the first ride. In his words, “The terms ‘easy to ride, effective, user-friendly and smooth’ are just code words for ‘slow’! Dick will be the first to tell you that he’s over the top when it comes to performance and that, honestly, most folks (including us) think the 2021 model runs just fine.

The Dicks Racing GasGas EX300 was not only graced with engine and suspension love, but Tusk wheels, NitroMousse foam inserts wrapped in Dunlop skins, and TM Designworks guides and a skid plate highlight the machine as well.

THE ENGINE MODS
So, he built his motor mods in two stages. Stage 1 is cost-effective and offers strong gains that every rider would benefit from. In production trim, the stock compression ratio is fairly low. He still wanted to use 91-octane fuel, so the head was modified based on that. This produced a noticeable improvement in overall pulling power. To improve fuel atomization and fight detonation, torque grooves were machined into the squish band of the head. This improved the engine’s ability to pull a taller gear.

Still looking for more low end, he removed the throttle body so that dual Quad Flow torque wings could be installed. These units effectively control the air as it flows through the body, eliminating turbulence and increasing air speed. Big improvement.
Price: $495

Stage 2 is all about making the machine into a veritable hot rod. Dicks believes that for larger riders (200 pounds plus) or those who like to live on the wild side and have the skills to handle even more power, these mods are quite deluxe. He says that it’s no secret that the big weakness of the 300 is that it goes flat and signs off early. Usually, he will make these modifications for MX applications where outpowering a 450 is required on the start. For this project, Dick wanted to do something special. This being his personal bike, he wanted the extra power.

To achieve this, he lifted the cylinder to raise port timing, which lets the engine keep producing power much longer without going flat. To compensate for the cylinder mods, the head requires more machine work to correct the compression ratio.

At this point, fueling must be altered to compensate for the engine changes. Dick chose to fit his machine with both a GET ECU and their injector relocation kit. The kit comes with a two-position map switch and Wi-Fi tuning capabilities via an app on your smartphone. The relocation kit moves the injectors from the cylinder side ports to behind the reeds. Its goal is to put fuel back into the intake air stream just behind the reeds, which in turn gets dispersed and atomized. The goal: more power. The cavities where the injectors used to be are blocked off with supplied plugs. With the cylinder already off, Dick filled in the holes left behind by the injector nozzles inside of the transfer ports.

Luxon triple clamps, SRT fork bleeders and a BRP under-bar handlebar mount with a Scotts damper in the cockpit.

Once the top end was buttoned up, Dick set about installing the new intake manifold that holds both fuel injectors. It was tricky to achieve proper fitment with the fuel hoses and connector, but with everything installed and running, the process of tuning the ECU for this specific engine package began. Eventually, Dick enlisted the help of a specialized GET tuner (Syndicate Development) that has advanced software tuning capabilities and a dyno.

The power gains were stunning but needed refinement. Dick knows that a dyno does not represent real-world off-road where the load is changing depending on traction and wheelspin. He used the Wi-Fi app to get the powerband tight, immediate and super strong. According to Wilk, the power gains were massive and possibly too much for tight, gnarly terrain, though he put considerable effort into making it usable.

His final step was fitting the bike with an exotic Italian-made Scalvini cone pipe and silencer. The hope was not that it would add more power but that it would instead smooth out what was already there. It did just that and sounded and looked full factory.

Stage 2 kit price: $1695, plus the Stage 1 mods ($495) and the Scalvini exhaust ($589).

An SRT sensor cover guards the TPS unit, and the GET relocation injectors sit behind the cylinder.

INTO THE SUSPENSION
The GasGas EX300 comes with WP AER air forks, and Dicks Racing believes that the forks are too harsh initially and ramp up (get stiff) too quickly. Both issues are the result of too much air pressure (130–150 psi), which is required to hold the fork up. Dick came up with a Hybrid AER design where the right cartridge is replaced with one that holds a single .50 spring.

The Quad Flow torque wing helps bottom power.

Internally, the cartridge features a hydraulic BCD (bottoming control device) that controls damping, enabling a plush setup that eats the big hits well. The left AER fork has the pressure reduced to 60 psi, eliminating harshness while retaining the light weight and tunability of the original design.

Out back, Dick believes that the shock works well in stock form. The trouble comes when you need a stiffer rear spring that is more than one size firmer than stock. The rebound damping can barely control the standard spring, let alone anything stiffer. Dick says that he’s 215 pounds, plus gear, which means 230 pounds total. The goal in modifying the shock was to re-valve the rebound to match the required 5.0 spring and provide a cushy feel on compression to work better in the rocks.
Price: Hybrid AER forks, $695 (2021 model), $795 (2017–2020 models); shock revalve, $21; spring, $130

Our test rider Ryan Koch praised the immediate power and its ability to yank to the moon. Also, the Dicks suspension improved feel, the ability to eat trail hack and help with stability.

THE TRAIL TEST
We have plenty of seat time on the current-generation TPI two-stroke models and know where they work well and where the engine lacks power. On our stock KTM 300XC, the bottom and midrange power are phenomenal, yet on deep sand hills the bike falls flat on the top end and lacks the pull needed to carry you over steep climbs. We countered this with power-valve adjustments and eventually settled on a higher-compression S3 head and aftermarket Coober ECU to gain the needed spunk for higher-rpm situations. After riding the modified Dicks Racing GasGas EX300, we were absolutely blown away. This bike was unbelievably far ahead of our semi-modified KTM 300XC. The Dicks Racing GasGas gained the needed midrange and top-end pull, and it was eye-opening how ridiculously gnarly the power pulse was on the machine.

The entire tone of the engine was deeper and meatier. This was easily the fastest 300 we’ve ridden to date. But, it still lugged down low and could negotiate trials-like situations like you would expect from a 300. It was beyond impressive how well the bike could maintain the aggressive pulling power needed for steep climbing or deep sand and never fall off the pipe or lose power.

The suspension on the Dicks Racing GasGas EX300 handled everything we threw at it. Amazingly, even though the settings were initially set up for a faster style of riding, we were pleased with how plush and balanced the bike felt in slow, technical riding conditions. At higher speeds, the suspension is plush yet firm and stable enough to be pushed with zero deflection or shake in the handlebars. The Scotts stabilizer also helps tremendously. The shock was as impressive as the fork, allowing the bike to be balanced and plush. We liked how firm the shock was for large hits, yet it would handle trials-like situations when we needed to load the rear end and make traction over the rear tire.

Top marks also go to the Seat Concepts complete seat. The cover is much grippier than the stock cover, and the seat offers a wider, plusher platform and foam. We love the STR bits on the bike, such as the rear rotor guard, and one of our favorites was the wider brake-pedal tip. The stock pedal is super tiny and easy to miss with your foot. The brakes and hydraulic clutch on the GasGas EX300 model are Brembo as opposed to the Braktec components that come on the GasGas EC300. These components are tried and true with the most consistent feel in the business.

This bike had monumental swings in power and handling manners. You may question the price of the modifications, but after riding with them, we can tell you that there will be no disappointment in performance. Each item contributes to the full package in its own way. Just one ride on a TPI machine with these components and you will be searching for ways to build one of your own. It’s a ripper.

All services and parts are available from Dicks Racing: (916) 705-3193, [email protected], www.dicksracing.com.

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