The secrets behind Precision Concepts Racing's 2019 Kawasaki KX450 off road race bikes – unearthing the build details, parts and work the team puts in to turn these Team Green missiles into enduro bikes.
Precision Concepts Racing is a well-established and successful team taking 12 titles in almost a decade racing. Competing successfully in America’s West Coast off road series’ like WORCS, Big 6 Grand Prix and Sprint Hero Enduro.
For the 2019 season, Precision Concepts is fielding the all-new Kawasaki KX450s with Zach Bell, Blayne Thompson and Clay Hengeveld, plus team manager Robby Bell.
What we’re interested in here are their bikes. What does it take to get a stock motocross Kawasaki into shape for off road and enduro racing? Kawasaki KX450s are clearly not common in enduro. Preconceptions about the work an MX bike needs to make it usable for enduro when there are easier options out there is obviously a factor.
The reality is many misconceptions put riders off. The 2019 model KX450, like all the current crop 450 MX machines, is lighter and much better suited to off road than they used to be even just a couple of years ago.
The latest models have sweet chassis’ and importantly engines and fueling happy to run at slower speeds without stalling. Most also now have electric start as standard and as an increasing number of riders prove, a few changes can easily make MX bikes work in enduro.
Anyhow, that’s enough talk about the reasons, what about the reality? To find out what Precision Concepts have done to get their 2019 KX450 Kawasakis ready to race we spoke to the man himself, Robby Bell, for the low-down on these great-looking machines. Let Robby take over…
Robby Bell: When we got the bikes, the motors were split, completely torn down and sent to CryoHeat to have the internals and cases micro-polished and treated with their proprietary process to decrease both friction and heat. The process improves performance (decreases rolling friction) and longevity (from the added fortification from the process).
The team uses an LA Sleeve piston kit for increased durability and power. Additionally, the Rekluse Core manual clutch offers smoother pull at the lever and better longevity and performance.
The Rekluse Manual Slave Cylinder helps with a little further modulation of the clutch for the riders. A Boyesen SuperCooler improves the efficiency of the cooling system, along with the MotoHose radiator hose kit, while Maxima Racing Oils offer their protective qualities and improved durability to the engine.
As for the power, the team has different in-house mapping curves to tweak the delivery depending on the terrain and rider preferences. Zach and Clay are very smooth with the power delivery, while Blayne likes to be a bit more aggressive. The 2019 KX450 powerplant offers plenty of low-end pull and Pro Circuit has developed custom exhaust systems for the riders, which help with a little more mid-to-top performance. Overall, the team focusses on reliability and ride-ability as much as pure power.
Comfort and aggression – handling goals
The handling goals are predictability and finding the balance between comfort and aggression. Though each rider has their own personal settings, the baseline for the team is a firm, plush and progressive fork that allows the riders to charge deep into corners, while still picking up the rough chatter.
This is matched with a fairly flat but compliant shock balanced between being active enough to be comfortable over small chop without lifting under braking, but be firm enough to handle any bigger hits.
Precision Concepts handles all the custom internal valving of the forks and shock and goes beyond the shims to chamfer and polish many internal parts of the suspension. In action, this offers a little extra comfort to the feel, while being able to keep the suspension firm enough for the speeds the riders want to push.
A Ride Engineering link arm helps quite a bit with the rear-end, namely improved bump absorption and helping keep the rear flatter under braking. Additionally, the Xtrig triple clamps offer a noticeable improvement in front-end compliancy, improving bump absorption feel and control.
Down to the ground
For the most part, the team bounces back and forth between the Maxxis ST and SI tires. The Maxxis SI is a great mix of performance and durability, while the ST is a more aggressive “race” tire. Nitromousse inserts keep a more natural feel (less “dead” than your standard mousse), and allow the riders to be more aggressive over the rocks and sharp edges without the fear of flatting.
The Galfer front brake rotor and Ride Engineering caliper offer more stopping power and better modulation. The team choses to run a 240mm Galfer rear disc (OEM is 250mm) in order to be a little less vulnerable to impact damage. A TM Designworks disc guard offers a little extra protection. Additionally, a TM slid-n-guide set provide better longevity and strength in the chain slider and guide departments.
Using stock gearing
In initial testing, each rider has stuck with the stock 13/50 gearing. The team uses Mika’s hybrid rear sprocket for the extra life and better chain wear, without adding too much weight. The RK MXU chain balances longevity with less weight and rolling resistance than most standard o-rings. Lastly, ZipTy’s axle blocks make adjusting chain tension and wheel changes much easier.
Blayne and Zach use Mika’s STV bend Pro series handlebar (the equivalent to a 996), while Clay likes the RC (997). Zach’s bars are cut to be a little narrower than standard. The ARC “textured” levers give a little more comfort and control, plus adjustability at the lever for each rider’s preference.
Ride Engineering’s billet kill-switch attaches to the front brake handlebar mount, clearing a little clutter on the bars. Zach and Clay like A’ME’s half-waffle grips, while Blayne is partial to their “Tri” version.
GPR’s V4 stabilizer adds damping to the steering, allowing the riders to loosen their grip a bit. The guys typically keep the stabilizer on setting one or two, for just that little bit of extra control.
The IMS tank gives the bike a little more width, but with the OEM tank being so slim, the riders have reported that the IMS actually adds comfort and gives them something to push their knees into.
IMS also makes the team’s foot pegs. Their SX sharp CORE pegs give greatly improved grip over stock.
Devil in the details
The Motoseat cover is adds a little grip and traction to the seat, a must with the powerful four-strokes like these.
The team build wheels in-house with Excel’s A60 rims and spokes and Talon hubs. Dubya is the main man in the team for wheel-building services and the only one they trust going to the start line with fresh-built wheels.
Acerbis plastics furnish the bike. Two notable pieces are the Raptor front number plate with extra material protecting the lower triple clamps and their plastic skid plate, which stands up to the demands of off-road racing, but is light and fits the OEM mounts.
Profilter handles the team’s oil and air filter needs. For the siltiest of races, the team will add an outerwear to the air filter for the added protection.
The team uses VP Racing Fuels’ MS98 on race weekends. No fancy power-producing fuel needed, the team is after the increased octane and consistent, cool burning of the MS98.
RAD Custom Graphics provides the graphics kit, keeping the consistent “Team Green” look to match Kawasaki’s supported teams. RAD also handles the wrap on the team transporter rig, along with other graphic and sticker needs, including some of the team’s apparel needs as well.
The Precision Concepts bikes are built 100% in-house by lead mechanic Phil Valdez. Owner Bob Bell is the mastermind behind the valving specifications, working with John Snyder (lead in the suspension department at Precision) to build the suspension for the riders, test with the riders to dial in their personal preferences from ergonomics, handling and power.
They sure are sweet bikes and we look forward to seeing how they perform during the 2019 season.
More information: precisionconceptsracing.com
Photo Credit: Spencer Owens Jon PearsonEnduro21 Editor and Bike Testerjon.email@example.com