2016 Yamaha WR450F: Suspension Set-Up

After living with our 2016-model WR450F project bike for six months, we’ve deduced that it’s pretty easy to improve the new-gen Yamaha’s chassis balance and handing without spending a bomb on suspension mods. Here’s how:

FRONT-TO-REAR BALANCE

Like the WR250F, Yamaha’s 2016 WR450F runs the same KYB suspension componentry as the YZ-F it’s based on, albeit with substantially softer spring rates in its twin-cartridge AOS-type fork (4.5N/mm, compared to the YZ450F’s 4.9N/mm coils), and revised valving in both the fork and shock to suit off-road terrain. On the rear-end, however, the enduro and MX models both run the same 56N/mm shock spring.

So it’s clear that Yamaha’s designers have 1) intentionally rocked the enduro model’s chassis forward to ensure it turns well in tight terrain, and 2) given the fork’s compression valving enough grunt to resist bottoming. And make no bones about it; the WR450F does turn well and it does boast excellent bottoming resistance. That said, the fork tends to ride low in its stroke when you’re standing up (which puts extra weight over the front of the bike), and as a result, I found the front-end is inclined to knife-under when pushed hard on singletrail. Which suggests the 2016 WR450F would benefit from firmer fork springs, right?

Well, the answer to that depends on your weight and speed and the terrain you predominantly ride. For casual ‘sit-down’ trailriders up to 85-90kg, the standard suspension package is super-forgiving and hard to fault. But for 90kg-plus riders who like to get aggressive and tend to ride more of the time in the standing position, a firmer set of fork springs is likely to create a better front-to-rear chassis balance. That’s exactly why Yamaha’s top off-road racers have gone several rates firmer with their WR450F race bike’s fork springs, while only beefing up their shock settings slightly, if at all.

Because I didn’t want to give up the fork’s plush ride in snotty terrain, I initially resisted a move to firmer fork springs. But after sampling a few of these Pro racers’ bikes, it’s finally convinced me of the need for change (I’m 86kg plus gear). So long as the compression valving is backed off (remembering that clickers tend to make a larger difference on MX-bike forks), the firmer fork springs definitely give the entire chassis a more balanced and predictable feel, without making the front-end harsh or inclined to deflect.

GEOMETRY & SAG

Before paying a workshop to dial your suspension’s internal settings, be aware that it is possible to markedly improve the WR450F’s ride with a few simple external tweaks. Here’s what has paid handling dividends on our project bike:

• I’ve shifted weight off the bike’s front-end by dropping the fork legs down through triple clamps (so that the fork caps are flush with the top clamp), while retaining 120mm of race sag in the rear-end.
• I’ve moved the handlebars into the forward mounting hole (with rearward offset bar mounts) to open up the cockpit and give me a stronger standing position on the bike.

Together, these changes have given the chassis balance a more neutral feel, without noticeably affecting steering feel and accuracy – thanks largely to the larger 25mm triple clamp offset, which makes the 2016 model’s steering more direct and responsive.

Stay tuned for a subsequent online instalment on this Transmoto WR450F project bike, once I’ve sent the bike to a professional suspension tuner to fine-tune the spring rates and valving in the KYB fork and shock.

In the meantime, check out our take on the top-10 bolt-on mods for the WR450F, and some video-assisted advice on how to use the Yamaha Power Tuner to modify the bike’s ECU mapping.