The MXA wrecking crew has the privilege of working with all different sorts of characters in the course of testing and building bikes. We deal with everyone from factory tuners to backyard mechanics, marketing men, parts changers, duct tapers, cool guys and not so cool guys?all with varied personalities and modus operandi.
One of the most pleasant to work with is Jeremy Wilkey and his crew at MX-Tech. Technically, these guys are incredibly knowledgeable and super-creative. We especially like them because they aren’t salesmen or desk jockeys. They are enthusiasts and tinkerers who love to improve the performance and technology of whatever they ride. Best of all, they are active riders who can’t wait to get on their bikes and try their latest tweaks.
We didn’t approach MX-Tech about building us a high-zoot, full-race 2009/2010 Honda CRF450 because no one else wanted to do it. We chose them because they have a reputation for accepting the most difficult challenges. And make no mistake about it, fixing the new generation of Honda CRF450s is daunting.
MX-Tech may only focus on suspension, but they know that suspension performance, chassis efficiency and even power delivery are all interdependent.
The MX-Tech Sprinter made the journey from Glendale, Arizona, to MXA’s SoCal headquarters with a freshly rebuilt project bike?replete with secret MX-Tech technology hidden inside. Rolling the bike into our photo studio, the CRF450 looked new, but on closer inspection, we noticed that the suspension showed serious use and there were wear marks from wrenches. It turns out that MX-Tech’s CRF had seen over a hundred shock rebuilds and test sessions.
MX-Tech suspension guru Jeremy Wilkey is a perfectionist, and we could tell by the look on his face that he thought he had something special. Finally, he couldn’t keep the secret any longer, and Jeremy told us about MX-Tech’s all-new, speed-sensitive bottoming control that is like nothing else on the market. After he showed us the internals and a couple of early prototypes, we were eager to get to the track and put MX-Tech’s CRF450 to the test.
SHOP TALK: FROM THE SUSPENDERS TO THE FENDERS
The crux of this project bike is MX-Tech’s speed-sensitive bottoming control for the forks. MX-Tech employs an independent internal cylinder, valve, shim stack and piston, similar to the primary damping of the fork, to control the end of the stroke. The advantage of this dual design is the capacity for virtually endless tuning to achieve precise bottoming control. Although they offer a traditional revalve, MX-Tech opted for their E7 gas fork cartridge system to take the speed-sensitive setup even further. This system reduces the compounding forces of the spring, compressed air and inevitable stiction in the forks. Finally, the stock 0.46 kg/mm springs were exchanged for 0.50s (however, the spring rate is effectively 0.48 kg/mm in the gas cartridge fork).
The shock received a rebuild and revalving and a polished shock body to reduce stiction and friction. For the latter, MX-Tech uses a levigated aluminum polisher with a special ball hone (from Kashima) that polishes without removing the coating.
The MXA test riders loved the Hinson six-spring clutch and Injectioneering throttle body mod. We run these mods on our own test bikes. The FMF Factory 4.1 pipe produced a healthy spread of power.
MX-Tech may only focus on suspension, but they know that suspension performance, chassis efficiency and even power delivery are all interdependent. So, they selected a set of 24mm offset Applied triple clamps and an SDI (Suspension Direct Incorporated) shock linkage.
Jeremy felt that before you could fix the suspension on the Honda CRF450, you had to address the nagging chassis issues. The SDI linkage is not so much a suspension mod as a chassis change. By making the initial part of the stroke softer, the linkage helps prevent the transfer of weight to the front end of the bike, which is already burdened on the Honda. By achieving less weight transfer with the shock linkage instead of valving, Jeremy feels he can keep an overall firmer setup.
As for the triple clamps, MX-Tech went for the super-short trail version (brought about by the 4mm offset change). Jeremy’s thought was that in the bumpy, high-angle conditions of motocross, the self-righting tendency of the trail arms becomes more of a self-steering tendency. The swap from 20mm to 24mm (which is the offset Honda used back in 2007) lessened trail.
For most of their project bike mods, MX-Tech sort of cheated. They studied every test of the 2009 and 2010 CRF450 in MXA and tried to implement as many of the successful changes as possible into their CRF450. The most obvious of these changes were Injectioneering’s throttle body modification and Hinson’s six-spring clutch. The throttle body mod consists of reconfiguring the EFI throttle body’s butterfly valve so it can open sooner for a more controlled burst of low-end power (plus it lessens flame-out). The result is a better flow and transition of flow for that first quarter turn. As for the six-spring Hinson clutch, it simply replaces Honda’s barely adequate four-spring stocker (and is exactly what Team Honda runs in their race bikes).
MX-Tech didn’t just revalve the forks and shock and throw them on a stocker. No. Instead they analyzed all of the handling factors that affected the performance of the CRF450’s Kayaba components and attacked them one at a time.
Other upgraded features included an HDR engine rebuild (to basically stock specs), FMF Factory 4.1 exhaust with MegaBomb header, Sanco coolant hoses, EBC 280mm oversized front brake rotor, Prographix decals, SDG gripper seat, and Pro Taper bars, grips, sprockets and chain.
TEST RIDE: HANDLING THE ROUGH AND TUMBLE
The first thing we noticed about the suspension was its firm setup. Many aftermarket suspension companies have a tendency to set up their suspension on the firm side, so don’t exaggerate your skill level when discussing your weight and speed. When MXA‘s faster test riders jumped on the freshly prepared MX-Tech CRF450 and pushed hard during hot laps, the suspension felt great. When the hot laps stretched into motos, we wanted to go softer. After backing out on the compression clickers, we achieved a much friendlier ride with very little sacrifice in performance.
To make sure that we were on the right track with the suspension, we went really soft. This was an effort to test the bottoming resistance of the hydraulic bottoming control in the forks. The softer settings enabled testers to really feel the entire stroke, and they came away impressed (especially after hitting fast bumps and big landings that would normally send a jolt of electricity through their wrists). The very last part of the stroke had phenomenal resistance to bottoming. The fast test riders thought that they could actually get away with running softer settings in a race (and, of course, the slower test riders were ecstatic that the MX-Tech suspension could be set up as soft as they wanted without fear of harsh bottoming). Overall, the
MX-Tech CRF450 project bike handled obstacles better and behaved in a more stable manner than our stocker, and it responded better to more aggressive riding.
The FMF Factory 4.1 and MegaBomb header with a stock engine produces plenty of horsepower in a very steady and metered manner. The Injectioneering throttle body modification perked up power for the first quarter turn of the throttle and helped get the engine revving quicker. Better yet, it cured the flameout problem. The package was deceptively fast.
Akin to the metered personality of the powerband was the EBC front brake rotor and pads. There was plenty of overall power, but it was slow in coming. Test riders enjoyed the control in slick situations, but wanted more response at first touch. The red carbon EBC pads are too mellow. We vastly prefer the sintered brake pads. We are careful about what we wish for, though, because a 280mm rotor with grabby pads is something to respect.
CONCLUSION: WHAT’S THE STONE-COLD REALITY?
Jeremy Wilkey and MX-Tech did their motocross homework, logged tons of development hours, and burned through prototypes that didn’t pass muster. The result? A totally unique, speed-sensitive bottoming control system that works like a charm. With its E7 gas cartridge system, shock tuning, chassis and power mods, the MX-Tech Honda CRF450 is a completely different beast from the stocker. The bike worked with the rider, whereas the stocker worked against him. MX-Tech’s R&D time paid off, and you can take advantage of MX-Tech’s high-quality and versatile upgrades.
Jeremy stayed on the West Coast for as long as it took for us to run his bike through the wringer (and when we weren’t using it, he logged some major track time). In fact, after we completed our test session and loaded up to head back to the palatial MXA Towers, the MX-Tech guys put on their gear and went out to try our suspension settings.
For more information, go to www.mx-tech.com