Tuned: 2021 YZ450FX Endurance Build

24 Hour Bike Build

A 2021 YZ450FX was the starting point for our 24 Hour build.

Building a bike to continuously run for 24 straight hours is pretty tough to do, especially when you have 4-6 different riders on the bike throughout the race. For 2021, we put all of our chips in on our ‘21 Yamaha YZ450FX. We piloted the bike in stock trim at the 10 Hours of Glen Helen earlier this year and that gave us a better view at what might help come time for the big 24 Hour.

Not much was done to prepare the YZFX for a day-long race.

Quite frankly, this Yamaha didn’t need a whole lot to make it race ready. In stock trim, the bike is very capable and very broad in who it appeals to. The motor, with adjustable mapping on the fly, can be tailored to just about every rider’s preferences. To go with that, Yamaha suspension is known to be very good and versatile across the board and this bike is no different.

TCS Powersports stiffened up the suspension to accomodate the Pro level riders onboard.

Our biggest mechanical change to the 450FX was a suspension revalve. TCS Powersports is a local tuner and has a lot of experience with west coast off-road, with Todd himself racing NGPC, WORCS, and GHR Endurance Races. The 450FX suspension has a good base, but for Pro level off-roaders who generally gravitate towards stiffer moto setups for GP racing, the stock valving is on the softer side. TCS went up a few rates on fork springs, along with valving, and updated the shock valving to match while using the stock rear spring. Todd pieced together some stock YZ450F moto valving to dream up the setup we ran.

GPR Stabilizer provided a Pro Kit to help minimize headshake in fast, choppy areas.

The next biggest change was a steering damper setup from GPR Stabilizer. We’ve run our smaller YZ250FX without a stabilizer setup for a year now and with no complaints. However, as you add power, everything becomes more finicky and the need for a stabilizer was a little greater with a big 450cc powerplant underneath us. The full Triple Clamp and Stabilizer setup was a nice touch for the 24 Hour.

The Modified Machine Works setup is pretty dialed in and we had no issues when racing for 12 straight hours through the night.

Lights are pretty important for a race that spans 12 hours in the dark. Modified Machine Works has a pretty solid setup using some Baja Designs pods and John Kilmartin with Kilmartin Racing was gracious enough to let us borrow an extra set of his lights for the race. Using an XL Pro and XL Sport, the total power draw was ~66W. The stock FX is only capable of powering ~36W, so we had to resort to another option to power the lights. Luckily, the WR450F and YZ450FX parts are mostly interchangeable, so we swapped out a stator and a flywheel for the WR components to get ~100W of output out of our FX race bike. The parts bolted on in a matter of minutes and we had no issue powering the big lights all race long. Support DBT and buy those parts from Rocky Mountain ATV/MC HERE!

IMS’s oversized tank and dry-break were a must for the 21 pitstops and 728 miles raced.

Other than those three changes, the rest were just basics. An IMS 2.7 Gal tank with a dry-break is a must have to let us go the distance and refuel in a timely manner. We were riding ~36 miles and 1:10 minutes at a time (4 laps) before switching riders, and we would generally see the low fuel light come on right as we were pitting, letting us know we had 0.5 gallons of gas left.

This is the map we ran the entire race. It offers a smooth, easy to ride power that never gets away from you but still offers enough power throughout the range.
MX53 Tires will go the distance and still work pretty good in the varied terrain we see at Glen Helen.

Dunlop helped us out with MX53 Tires front and rear for this race. Durability proved to be really good with the tires on the varying Glen Helen circuit. A lot of hard packed dirt, silt, rocks, and some pavement made up the terrain. We ran one MX53 for the entire 24 hours and used three MX53’s out back. We changed our first MX53 at Hour 8 when we put lights on, though it still looked really good. The next MX53 lasted us all night and would’ve stayed on longer but we had a small mousse issue that forced us for a premature wheel change after 12 hours. The last tire went to the finish for the final four hours and still looks great.

We stretched our MX53’s to up to 12 hours of riding time and still had tread left to spare.

Nitromousse kept us flat free throughout the race. We ran 21-220 mousse’s in our 80/100-21 front tires and 18-305 mousse’s in our 110/100-18 rear tires. The front still feels brand new in the tire, showing its durability is as good as any, if not better. The rears mostly lasted pretty good, but we had a hot spot in our mousse that gave out after 12 hours of fast racing and that led to a wheel change.

TM Designworks and Mika Metals freshened up our drivetrain setup.
The TMD Rear Disc Guard is beefier than stock and bolts to the stock caliper hangar.

TM Designworks refreshed our plenty worn Chain Guide and Slider for a beefier setup. We’d feel comfortable running a stock chain slider but it was worn all the way through to the swingarm after 40+ hours. A TMD Chain Guide is something we’d replace anyways for a race like this since they’re stronger and can take more abuse from rocks and debris. Additionally, we got a little better Rear Disc Guard that was stronger than stock as well. 

Mika Metals Sprockets and a Sunstar XTG Chain kept us rolling all race long.

Mika Metals reinvigorated our Sprockets with a stock 13/50 setup and we replaced the worn stock chain with a Mika O-Ring chain. We did have to adjust it once after eight hours, but we didn’t get a chance to stretch it before so it stretched a tad as we started the race. AME Grips kept our hands blister free, though the soft compound was a little worn out by the end of the race. 

MotoSeat updated our seat cover for a grippy yet non-abrasive seat cover.
DT-1 Filters kept our bike breathing fresh air with their triple layer filter.

MotoSeat replaced our worn stock seat cover. The grippy yet less abrasive material was welcomed by all of the riders and kept our rear ends feeling fresh by the end of the race. RAD Custom Graphics gave us the Chad Reed look with some 22 plates! Finally, Acerbis protected our hands with some X-Future handguards.

The complete build wasn’t far off from stock but it proved potent as it won the 2021 24 Hours of Glen Helen outright!

Do You Like DBT Bringing You Fresh Content? Search and Shop Through the Links Below: