Racing A Nearly Stock YZ450FX
Story by Trevor Hunter, Photos by Trevor Hunter/Jerbal Shots
As we do nearly every year, we use the Glen Helen Endurance Series as a proving grounds for our competition off-road bikes. And here is where the ’25 Yamaha YZ450FX enters the chat. Our go-to bike for the annual 24 Hours of Glen Helen, we received our test unit early this year and figured the best way to test it and break it in is to go racing! With ~7 hours on the bike at the Glen Helen NGPC round earlier in the month, we got a good feel for it in completely stock trim and we wanted to add a couple different mods to get it race ready to compete for the overall win at the 6 Hours of Glen Helen. We were blessed with the best track conditions we could ask for, but in return were faced up against 198 teams on a sub-12 minute laptime for us Pro’s. This led to A LOT of lapped traffic and quite possibly the roughest Glen Helen off-road we’ve ever seen. What started as hero dirt turned to square edge, slightly dry and hard pack with some massive whoops and big breaking bumps littered throughout the course. With that, we got a great test out of the YZ450FX and learned about some tweaks needed to fine tune the stock setup, all of which we’ll post in the coming days!
To start, we’ll cover the bike and some of the mods we made ahead of race time, as well as why we did after putting some time on it completely stock earlier in the month.
The engine on the FX is a monster. We had plenty of power on tap at all times and we could pull any modified 450 at any time up the hills and in the fast straights, as long as we were willing to twist the throttle that hard. The sheer amount of power the Yamaha puts out sounds intimidating, but we really enjoy it simply because if we need or want it, we have it. Also, it allows us to ride the bike smooth, or “lazy”, and roll taller gears at lower RPMs and not work to put the power down. When ridden like that, it is very fun and rewarding and doesn’t tire you out as much as you’d think, so long as you respect the power.
If we were to make some changes, we’d like to smoothen out the jerkyness of the throttle at low RPM, low throttle opening situations. With the good dirt and lack of singletrack on tap, we didn’t feel the need for it at the 6 Hour but in our initial ride, we did feel this could be improved so we’ll play with mapping and see if we can address it through the GYTR app.
As stated earlier, we struggled with some front end grip and feel despite having the added comfort and compliance. In some post-race testing, we found that dropping the forks to 3mm, running compression at 8 clicks out, and slowing the rebound down 1-2 clicks adressed the front end grip issue and helped balance the bike out with a less active and busy front end while running the engine mount mod.
In stock trim, we feel a front end harshness under heavy loads and the motor mount mod addresses this which tells us it’s more of a chassis thing than a suspension setting. Previously, we’d look at softening the fork to find added comfort, but with the small chassis change, we found ourselves using a lot of the stroke and went stiffer up front to compensate. We ran sag at 100mm as that’s the sweet spot on this bike, and we backed out the high speed compression on the shock 1/4 turn for added compliance on decel. We started at 1/2 turn out, but with how good the traction was and how hard on the gas we were, we felt the rear end would squat too much under acceleration and upset the chassis.
