When the MXA wrecking crew needs insight into how to get the most out of a Yamaha YZ450F, we call Doug Dubach. Doug is an encyclopedia of all things YZ. Not only was he a Team Yamaha factory rider, AMA Supercross winner, the first rider to win an important race on the production YZ450F, owner of DR.D Racing and a 26-time World Vet Champion, he was also the head test rider for Yamaha during the development of every YZ450F. And Doug didn’t just test the YZ450Fs for the factory—he raced them, winning 22 of his World Vet Championships on a YZ450F (the other four were on YZ250 two-strokes).
So, when the MXA wrecking crew set out to build a better 2018 Yamaha YZ450F (the mods apply to both 2017 and 2019 YZ450Fs), we decided that the best plan would be to borrow Doug’s personal YZ450F (the one he took his 26th World Vet crown on). After we had ridden it, photographed it and raced it, we had Doug tell us everything he did to his Dubya World Vet Champion YZ450F. You’ll be surprised how simple it is to make a Championship-winning bike
THE SUSPENSION. Enzo has done the work on Doug’s race bikes for decades, and even though Kayaba SSS suspension has been top-ranked since 2006, Doug has some special needs that Enzo addresses.
Forks. Doug is on the light side for a 450 rider, so he exchanges the stock 0.50 N/m fork springs for lighter 0.49 N/m springs ($110). Enzo adds its proprietary spring tubes ($250) and re-valves ($180) the forks for more compression damping at the end of the stroke. Doug wants his forks to slow down deep in the stroke and feels that the stock forks are way too quick near the bottom.
Shock. Doug runs the stock 56 N/m shock spring but has Enzo work on the compression damper so that the clicker settings have more pronounced differences from click to click (on the high-speed adjuster). The re-valve is $180 (with $15 for the fresh oil).
THE ENGINE. With the exception of the DR.D exhaust system ($670), the hard parts of Doug’s engine are bone stock. Hard to believe that a guy who was a Yamaha factory rider doesn’t ask his old buddies in the race shop to slip him some works parts, but Doug says he doesn’t need more power—or want more power. Instead, he likes a smooth, strong, filled-in powerband with no burps or giggles in the curve. Even with his exhaust system, Doug wants no frills. He doesn’t run fancy titanium tubes or a carbon fiber muffler; he sticks to the durability of stainless steel tubes, an aluminum muffler and the standard DR.D magnesium end cap.
Although there are no internal changes to the engine package, Doug does move the complete powerplant forward 1.5mm to get a little extra bite on the front wheel. DR.D sells a kit that makes it a snap to move the engine forward. Be aware that Doug does not rotate the engine downward but keeps the cylinder at the stock angle. The DR.D part is a simple, eccentric swingarm pivot bushing, which has the hole for the swingarm pivot bolt drilled to one side so that the engine can be moved forward with very little modification. The stock front motor mount plates don’t need to be modified, as they can be wiggled to line up, but the bottom motor mounts (under the engine) might need a little file work for clearance.
MAPPING. Doug used his cell phone to install the Travis Preston map in his black box. Doug tried many different maps, making them with his phone, but he always returned to the Preston map. As you can tell by looking at the Preston map, it is richer on fuel below half throttle in every rpm, and the ignition is advanced in seven of the eight boxes below half throttle (the only twist is that it is slightly retarded at 30-percent throttle at 5000 rpm). Every MXA test rider thought the Preston map was appreciably better than Yamaha’s stock or suggested map. The remapped YZ450F made more horsepower and torque at every spot on the curve. In the meat of the YZ450F’s powerband, horsepower was up by as much as 2 horsepower (torque was up 0.90 pounds-foot). Best of all, peak horsepower was moved down from 9700 rpm to 9200 rpm. That 500-rpm difference allowed Doug to use the existing power more efficiently (without having to keep revving the YZ450F past the bravery limit).
GEARING. Although the gear ratios were unchanged from 2017 (although second, third and fourth gears are 1mm wider in 2018), Doug went up one tooth on the rear (from a 48- to 49-tooth sprocket) to lessen the workload on second gear by getting to third gear sooner. By going lower on the gearing, Doug was able to stop revving second gear and get the YZ450F to pull longer in third.
CLUTCH. Doug’s YZ450F uses a Hinson clutch basket, inner hub and pressure plate, but he insists on running the stock Yamaha clutch plates (steel and fiber).
BRAKES. Doug put a lot of thought into his front brake. Instead of the stock 2018 Nissan master cylinder, caliper and rotor, Doug has a mix-and-match setup that he has been running for the last eight years. The master cylinder is a Brembo unit from a 2012 KTM. The stock Yamaha brake hose connects the Brembo unit to a 2007 Yamaha YZ450F front caliper, which grips on a 270mm works brake rotor (a part that his buddies n the race shop gave him). It is a non-wave-style rotor because Doug feels that the round rotor performs better when the heat builds up.
HANDLEBARS. Doug likes the stock Yamaha handlebar bend and alternates between the stock bars and Pro Taper’s matching bend. What he doesn’t like is the 2018 YZ450F bar mounts. The 2018 bar mounts are 5mm taller than the 2017 mounts, and when you combine that with the 9mm-lower seat height of the 2018 chassis, the bars feel way too high for Doug. So, he puts the 5mm-lower 2017 bar mounts on the 2018 triple clamps.
WHEELS. Doug runs the stock Yamaha wheels—blue rims and all.
MISCELLANEOUS. The graphics are custom DeCal Works designs. The air filter is by DT-1. The chain is a GYTR gold chain, which Doug claims will last forever. The seat cover is from Seat Concepts; it is the Super Grip model with rubber-octopus suction cups on the sides. Oil is by Maxima, and the 49-tooth rear sprocket is an optional Yamaha sprocket.
WHAT WAS IT LIKE TO RIDE?
Although we’ve known Doug since 1980, the last time we tested one of his race bikes was back in 2010. So, we were interested in how he would approached the vastly improved 2018 model. And, in truth, it didn’t need as much trickery as Doug used in 2010. That bike had a radiator lowering kit (24mm), triple clamps with 2mm less offset (from 22mm to 20mm), a softer-than-stock shock spring, the stock fork springs and a DR.D stainless steel exhaust system that cost only $620 ($50 less than the 2018 exhaust). But, all in all, it had all of the Dubach details of a conservative approach (stock bars, bigger rear sprocket, DeCal Works graphics, Enzo suspension and the same filled-in powerband—achieved with stock engine components).
With little more than an exhaust pipe, one tooth on the rear sprocket and a phone call to get the Preston map, Dubach’s 2018 YZ450F powerband was infinitely usable. Yamaha’s engineers worked hard to fill in 2017’s dead spot at 6000 rpm, and Doug’s setup was even better on the climb up the front of the curve. The old jolt after 6000 rpm was replaced with a long, steady, metronome-style of power. Lots of power without a lot of drama. The boost in ponies in the middle and on over-rev was a delight. Best of all, we didn’t have to spend $5000 to get this kind of power. It cost us $730 for the DR.D exhaust and rear sprocket (the map is free—after you pay your cell phone bill).
What were the things we loved? The gearing change made the bike much easier to ride. It could scare you if you hammered it in second gear, but why would you do that when it pulled so strong in third? Plus, full throttle in second gear isn’t half as fast as half throttle in third gear. The Travis Preston map is worth the time to download—or simply have a friend with an iPhone do it for you. Doug’s Brembo front-brake combo was much stronger than the stocker, plus it didn’t have the grabby feel that Nissin calipers deliver with 270mm rotors.
As for the Enzo suspension, we were afraid that it would be Supercross-stiff. It wasn’t. That’s because our test riders weighed about 30 pounds more than Doug, and the settings were super tunable. We changed a few clicks, set the sag at 105mm and had no issues. Great stuff. We liked that this was really a stock motorcycle tuned to the erudite tastes of a talented rider. Doug knows what he wants, but even more significant, he knows what he doesn’t want. Thus, no fluff.
As we stated in our 2010 test of Doug’s YZ450F: “There used to be a Packard car commercial in the 1940s that said, ‘Ask the man who owns one.’” The implication was that a Packard owner would know if the car were good or bad. That is how the MXA wrecking crew feels about Doug Dubach and the YZ450F, except we’d change it to: “Ask the man who built the bike.” Doug Dubach knows the YZ450F better than anyone on the planet.
For more information go to www.dubachracing.com