YAMAHA FZ-09 | Doin' Time

Mods: Race Tech fork springs, Maxima fork oil, ZX-6R shock, Suzuki hardware

Yamaha FZ 09

YAMAHA FZ 09 Doin Time

YAMAHA FZ 09 Doin TimeKevin Wing

WRIST: Ari Henning
MSRP (2014): $7,990
Miles: 3,250
MPG: 37
Mods: Race Tech fork springs, Maxima fork oil, ZX-6R shock, Suzuki hardware

With the help of Assistant Editor James Laub, I finally dug into the FZ-09's suspension, and we managed to make strides for not a lot of money. For the fork, we followed the usual formula and replaced the stock 0.75kg/mm springs with 0.90kg/mm Race Tech coils (racetech.com; $110) and poured in 10-weight Maxima fork oil (maximausa.com; $6.50/16 oz.) to increase damping.

Figuring out an affordable fix for the shock proved a little bit harder, but thanks to some resourceful folks on an FZ-09 web forum (yamahafz09.com), I learned that various Kawasaki Ninja shocks would fit. Using info from the forum and parts fiches, I found a lightly used, fully adjustable shock from a 2009 ZX-6R for $65.

Ari Henning
Ari HenningKevin Wing

Be warned, the ZX shock is not a drop-in replacement. It fits, but it takes some finagling. First off, the lower clevis takes a smaller bolt than the stock shock. No problem, "Skooter65" on the aforementioned forum found Suzuki SV650 parts (a bushing, bolt, and nut) to make it fit, and you can pick everything up online for $12. The next hurdle was making room for the shock's piggyback reservoir. Mounting the shock with the reservoir forward and facing up was the only option and required jettisoning the charcoal canister and trimming the plastic tray under the seat. Does that sound like a lot of work? It was, but all told we'd spent just $200 on parts. Not bad considering aftermarket shocks start at $650. Like I said in the beginning, we'll see where cheap fixes get us before going for the big-ticket items.

So how does it work? The 0.90kg/mm fork springs are a big improvement. Sag is where it needs to be with minimal preload, and the fork no longer dives alarmingly when I grab the brakes. Damping is still an issue, though. Initially we tried 7.5-weight oil, but it didn't make much of a difference compared to the stock 5-weight oil. Even with 10-weight fluid, low-speed damping is still too light in both directions, while high-speed compression damping is too severe. Further improvements will have to come by way of revalving the damping piston or, more likely, replacing it entirely. And, possibly, adding a cartridge to the other fork leg.

YAMAHA FZ 09 Doin Time
In place of the FZ-09's under-damped shock, I tried a fully adjustable shock from a 2009 Kawasaki ZX-6R. It did fit, but not without modifying the bike, and making adjustments to the spring preload and compression damping require its removal.Kevin Wing

The shock is a mixed bag. It's longer, so the FZ's sagging rear is elevated 15mm, and I like what that does to the riding position and steering behavior, but gaining access to the compression adjuster and preload collar is a real pain—as in removing the shock, which necessitates removing the seat and tank. Also, the ZX spring is actually softer than the FZ spring, but I figured if the damping was close then re-springing the shock would still be more affordable than an aftermarket option.

I'm happy we're making progress, and this setup might work for some riders—especially DIYers on a budget—but I'm not satisfied. Next I'll begin investigating custom options but still with an eye toward economy.