Going For Gold
FMF and Precision Concepts help us liven-up the little RM-Z and see how far a few basic upgrades can go.
Suzuki’s RM-Z250 may not have been a top contender in our 2018 250F Motocross Shootout. In fact, it came in last place. True, the Zook leaves a little to be desired when ridden back-to-back with the rest of its class, especially in stock form. Still, the 2018 RM-Z250 is a sharp machine with a lot to offer, and we were drawn to its strong points, such as its user-friendliness and excellent handling. We were happy to keep it in our garage for the year, and after spending more time with it we hypothesized that with only a few basic upgrades, it could be much more competitive with the 2018 field. Through the help of FMF and Precision Concepts, we got to work on the yellow bike to see if we could make it shine.
PHOTOGRAPHY BY JEAN TURNER
After getting an overhaul in 2016, the little RM-Z got no more updates for the next model years, sending it into 2018 with little more than BNG treatment (bold new graphics). It made the RM-Z pretty long in the tooth and what we called “one of the heaviest and most dated 250s in the class.” Among our complaints were the soft power, the overall weight and the KYB PSF2 air fork that we couldn’t seem to dial in. But among our praises of the bike were its stable chassis and sharp handling. And that right there is a good foundation to work with.
It’s not always easy to make a powerful bike handle better, but it’s very possible to boost power on a good-handling bike. In this case, it was extremely easy. FMF supplied us a full system for the Suzuki, a PowerBomb pipe and PowerCore4 silencer. It’s difficult to overstate how big of a difference this made in the RM-Z. The freer-flowing power was immediately noticeable, quicker revving and more responsive, with improvements throughout the entire rpm range. “It’s like someone pulled the sock out of the airbox,” one of our testers commented. Why Suzuki feels the need to cork up the stock exhaust so much, we’ll never understand, but know that a substantial power improvement is a mere pipe away. No engine work, no boring out the airbox, no fancy tuning or expensive race fuel—just let her breathe and watch her come to life. We should also note that a slip-on won’t quite do the trick, but the FMF full system is a significant improvement.
The Suzuki’s weight was another factor that held it back against its classmates, and while the FMF exhaust might have moved the needle in the right direction, it obviously doesn’t render the entire difference. That being said, a quicker-revving engine can notably affect how heavy a bike feels. Mellow power can make it seem heavier whereas crisp, responsive power can make it feel much lighter on its feet. The brighter power gives the RM-Z a lot more pep, and any extra weight is suddenly less of a factor.
More power on tap adds quite a bit of appeal to the RM-Z250, but is it enough to boost it to a more competitive level in its class? On its own, not quite. There still stands the greater challenge of the suspension.
It was time to take a look at the Kayaba PSF2 air fork. This is where task got a little more complicated. There is the very tempting option to simply swap out the pneumatic-spring fork with coil-spring components, but our goal was to work with the system at hand and see how much performance we could improve from a standard re-valve.
In our quest to find a suitable shop to perform the task, we looked to the off-road powerhouse Precision Concepts Racing team. Robby Bell and his crew obviously have the expertise to work well with the Kawasaki air fork, with racers Blayne Thompson and Justin Seeds on the podium regularly at GP events such as WORCS and the West Coast Grand Prix. To our delight, Robby and his dad, the renowned Bob Bell, were eager to take on the task of dialing in our little RM-Z to see how manageable we could make it.
As for a specific target for our suspension re-valve, we had Precision Concepts dial it in for me, a women’s expert-level rider. Since I not only enjoy motocross, but also riding and racing off-road, we requested a GP-spec. As we pointed out in our 2018 250F Shootout, the little Suzuki has a docile and confidence-inspiring nature, and that translates to a very versatile machine that is capable of being a well-rounded bike. Since plenty of people (myself included) ride a combination of track and off-road—not strictly one or the other—it made sense to split the difference in this real-world project.
While the suspension spec was dialed in specifically for me, we still had some of our heavier and more advanced test riders put in some laps aboard our “project” RM-Z to get more feedback on our upgrades. The results were unanimous. The power is a stunning improvement, and the suspension is a very positive change, but not what we’d call a miracle fix. The KYB PSF2 air fork has its limits, but a good re-valve, like the one we got from Precision Concepts, can go a long way in creating a good balance between the top-of-the-stroke plushness and the bottom-of-the-stroke support. This was a point of contention in our original tests, but the Precision Concepts re-valve allowed a greater level of rider comfort on the small chatter without sacrificing good hold-up on the front end.
In this test we also learned how sensitive this bike is to triple-clamp torque specs. It’s tricky finding the sweet spot on this fork and once you’re there, it’s easy to throw it off balance again by simply over-torqueing one bolt.
We had Precision Concepts dial in the shock, as well (even though we didn’t have any specific gripes about it in stock form), and the result was a polished and well-balanced suspension package. As we mentioned before, the fork fix wasn’t a cure-all, but a satisfying improvement. My hands/wrists are always my weakest link, so a harsh fork will spell an early end to my day on the bike, and that was often the case on the stock RM-Z. Flat landings or slap-downs were particularly punishing, sending a spike to my wrists that I could only endure for so long. After the Precision Concepts re-valve, that harshness in the initial stroke was largely worked out. It was particularly noticeable on bigger hits—the kind where you have time in the air to think, “This is going to sting.” A few times I braced myself for the harsh re-entry, but was very pleased to find a much smoother landing.
The more forgiving nature of the suspension is a welcome (necessary) upgrade on a bike like this. The precise handling and stable chassis of the RM-Z dare you to push harder, and with improved suspenders, you can do so without the fear of taking a wrong step and wrecking your wrists.
Even with the PC-tuned suspension, the PSF2 still isn’t as capable through the chatter and braking bumps as we know coil-spring forks can be. But the action is consistent and predictable, keeping a good front-to-rear balance, and yes, smoother overall.
The RM-Z is also a blast off-road, especially on single-track where its razor-sharp agility can really shine. I know, this is a motocross bike and not designed for trail riding. But there are few things in life quite as grin inducing as scurrying through bushes on a 250F like a scared rabbit. Guilty, your honor.
If the RM-Z250 was your only bike, you could very well get along with this suspension package just fine, but when you know how good today’s suspension can be, it’s hard to accept anything less.
Like the rest of the Japanese brands, Suzuki appears moving back toward the coil-spring fork design, and we’re glad. It already did so with its 2018 RM-Z450, and the 250 has followed suit in 2019. Hopefully it will help elevate the yellow bike to a more competitive status, but until then, we can say with confidence that there is room for performance improvement on the Kayaba PSF2 air fork with a proper re-valve.
In The End
With our simple upgrades—FMF full-system exhaust and Precision Concepts suspension re-valve—we found ourselves with a much more appealing machine. The Cycle News RM-Z250 has a lot more spark and offers a smoother ride, and those upgrades could well have placed it a lot closer among its competitors in our 250F comparison.
But whether or not it’s the fastest or the fanciest of the bunch, for a rider of my particular skillset, the RM-Z250 has a lot to offer. It’s a versatile, dependable, easy-to-ride bike that I feel confident taking just about anywhere, like the golden retriever of the 250F class. Some might prefer a pit bull on the track over a golden retriever, but here’s the thing about pit bulls—they might be faster in the hands of a pro, but they’re not going to boost your skill level. There’s a lot to love about a bike you can do more with.
While it may not have bells and whistles like electric start, map switches or traction control, it also doesn’t have the price tag to match. The basic elements are there, with decent fit and finish that won’t have you immediately shopping for a new handlebar and footpegs.
Speaking of price, that’s also where this bike gets interesting. The “official” MSRP of the 2018 Suzuki RM-Z250 is $7749, but a quick search on CycleTrader.com will show you how little that number actually means. Considering there is an all-new RM-Z250 in the queue for 2019, that means big discounts on the remaining 2018 models. Eyes akimbo for some smoking deals, kids. And a fat factory discount could more than pay for the exhaust and suspension re-valve that you’re probably going to get no matter what brand you buy, right?
The Suzuki suffered in our 2018 250F comparison, but just as we suspected, a few turnkey upgrades will quickly elevate the RM-Z250 to a much more competitive level. Add to that the dependable, well-rounded nature of the Suzuki and you could have a great bike for the right rider. CN