Facebook Marketplace Finds: Suzuki RM-Z450 DTX Flat-Track Bike

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lot of folks love to customize and tinker. I’m not one of them. So it’s going to be hard for me to buy the motorcycle I want unless it rolls off the assembly line as a production bike. Problem is, no one makes a production flat-track bike. So if you want, you best be ready to roll up your sleeves… Or just check out Facebook Marketplace.

That’s exactly what I did when the flat-track bug bit me. So there I was, browsing the “Flattrack Swap & Shop” a Facebook group devoted to those who want to buy, sell, trade, or swap anything related to going fast (or slow, I guess) and sliding in a counterclockwise circle.

Bam, there it was. A clean 2015 Suzuki RM-Z450—lowered and on 19s—and relatively stock. Perfect. A couple of messages back and forth, some honest haggling, and I had the confidence to send over a bank transfer for five grand, sight unseen…aside from really nice smartphone Facebook photos, that is.

Turns out if you live near a major city, it's not that hard to ship a motorcycle cross-country thanks to Forward Air. The trucking company offers specialized metal containers that protect your machine from damage and erratic forklift drivers. Swing open the doors, roll it inside, and secure it with tie-downs. Fork over a couple hundred dollars and a few days later my shiny new-to-me RM-Z was on hand at Forward Air's location near LAX airport. I drove up in my pickup, freed it from its metal cage, and brought her home. It was that easy.

Thankfully, the guy I bought it from was an honest man and my yellow 450 showed up exactly as advertised. Closer inspection showed that it had a older-generation Showa single fork instead of the Triple-Air Chamber front suspension fitted for MY 2015. However, that’s a good thing as the spring version functioned better that the air setup—at least in motocross configuration.

Durelle Racing Products out of Colorado shortened the suspension and resprung and valved it. Because that's what you do to make a motocross bike flat-track-ready.

“Internal fork and shock spacers are machined to limit travel and set the ride height. That’s specific to the rider,” says Davey Durelle of DRP. “Compression and rebound valving stacks are changed and spring rates are increased over a stock MX setup. You want to have more control over the suspension since the terrain is much more smoother.”

The setup works reasonably well for my 175-pound chassis, despite being a few pounds lighter than the weight of the previous owner. A few clicks plus or minus here, a turn of preload there, and the suspenders work well at any of the local SoCal short tracks. Although with the amount of seat time I’ve recorded over the last couple of months, it wouldn’t be a bad idea to yank off the suspension for a refresh. After all, suspension fluid, like anything else, breaks down after time.

My flat-tracker rolls on a set of black Excel 19s and matching gold hubs, with a 2.15-inch-wide front rim and a 2.5-inch-wide rear. Some opt for a wider rear width, but this setup seems to function well. Durelle says you generally want a wider rim if you’re riding hardpack and a skinnier rim if the surface is more loose.

The bike came outfitted with a decent set of Maxxis DTR-1 rubber in sizes 27 x 7-19 front and a 27 x 7.5-19 rear. After I wore those out I installed a set of Mitas. The Euro rubber offers incredible grip but employs a stiffer sidewall, at least compared to the Maxxis. I prefer the feel of the Maxxis rubber, so I’m going to continue down that path once the Mitas rear wears out. The neat thing about dirt track is that since you only turn left, you can flip the tire and run fresh tread when the tire wears. It’s like getting two tires for the price of one!

The bike came with a stock exhaust, which I ran for a while. Right after my first ride, I installed the supplied “rich” gray fuel plug/map that’s designed to smooth out the powerband. Even with it installed, the RM-Z had a hiccup in terms of on/off throttle response. I rode around the problem by applying constant brake pressure when accelerating off turns.

Eventually, I bolted on a used Yoshimura RS-4 exhaust that I had lying around my garage—titanium remnants of the pipe I ran on my old ’12 RM-Z450 motocross bike before I sold it. And voilà. This pipe dramatically improved initial engine response when the right grip was twisted while also affording a broader and even smoother powerband. Twistgrip response could still be improved, but it’s going to require some ECU mapping to get there. Something I’m keen to explore in the future.

With imagination and the power of the internet, not to mention a bit of patience, getting into a new segment of motorcycling is easier than you think. For a little under six grand I finally had a machine that I could slide around in circles to my heart’s content. Now what other color bikes can I add to the garage…