Suzuki RM-Z250 2016
Suzuki has cooked up a completely new 250F for 2016 – it has a new frame, new motor, and new suspension – yet the bike retains the old plastic. It’s like Suzuki didn’t want to flaunt the changes, they just wanted to deliver the performance.
The biggest change is the motor. It has 80 new parts when compared to the previous model. In short, the motor is designed to be more efficient and have broader power with a quieter sound output; the engineer’s spec’d a 94 dB sound limit, then took the challenge not to lose any thrust with the quieter exhaust. To boost the horsepower, they built a new piston, rod, bottom end, intake and exhaust cams, intake valves, and piston compression ring, among other things; the compression ratio increased slightly from 13.5:1 up to 13.75:1. The previously mentioned quieter muffler is mated to a 40mm longer header.
Also a top priority was to reduce engine braking, and that means smaller diameter crank wheels (for less drag through the oil in the bottom end) and an enlarged oil passage out from the bottom end to reduce crankcase pressure. Even the angle of the throttle body was changed in an effort to minimize compression braking. The bike still comes with two optional EFI couplers to make a +4% or -4% jetting change, literally a snap.
The engine has Suzuki’s Holeshot Assist Control (S-HAC), which has two start programs that each have three stages – launch, getting over the gate, then a transition back to the normal map. It works mostly with the ignition, not jetting, and retards the ignition for the first two stages then uses the third stage to transition back to the normal map. The mode is selected by a button on the bar, and once activated stays active until the throttle is closed, the bike is shifted into fourth gear, or after six seconds. Basically, the bike knows when you launch, and times out the right power for a holeshot. One map is set for slick conditions, one for good traction starts.
Like its big brother, the RM-Z250 has gone to an air fork, but the 250 gets Kayaba’s PSF2, the second generation of the original air fork. The fork’s air spring is simple to adjust – each fork leg has one adjustable air chamber, and each air chamber should be set to the same pressure (stock is 34.1 psi). Not to be outdone by the adjustability of the three-chamber air forks on the market, the Kayaba fork offers four clickers – rebound and compression, both with a high speed and low speed circuit. We’ll cover the fork’s performance shortly, but as for set up, this fork is nicely simple – check the pressure in each leg (Suzuki will give customers a fork pump/gauge with the purchase of the bike until the end of the year) and set the clickers. If dual clickers for each setting seem too much, just use the low speed clickers until you really want to spend some time dialing in, then incorporate the high speed clickers into your settings adjustments.
And the frame is also new. It now uses the RM-Z450’s head tube and has its own new pieces that connect the main frame spars to the bottom of the frame/swingarm pivot, and new lower frame rails/engine cradle. Suzuki tells us the frame is designed for better rigidity and balance, and also dropped in weight by 2.5% compared to the 2015 250’s frame.
Engine: Immediately the first thing that jumped out to us was the free feeling engine. The RM-Z250 revs more freely than last year’s bike, also you can definitely feel less engine braking on de-cel, especially when you let off on jump faces. While we didn’t get to ride the 2015 RM-Z250 back to back (as we have tons of time on the older model) we did recognized less throttle response and slightly less bottom end pulling power on the new 2016 version. It’s not a dog by any means, but it feels like Suzuki took the edge off the initial hit some. But, don’t let that get you down on the Suzuki, because the mid range to top end pull is lengthened and better than ever. You can feel more meat through the mid range when you are transitioning from second to third gears. Little “Suzi” pulls harder through deep loam and can hold second and third gear longer down long straights. Pala Raceway had tons of fast straights to test the top end out and it’s confirmed that the short shifting nature of the 2015 RM-Z250 is gone. The 2016 Suzuki can be revved out farther in each gear and is a much easier bike to ride. We tried all of the couplers provided by Suzuki and we preferred the standard ignition coupler. The “lean” coupler gave us some of that throttle response/bottom end back (similar to the 2015), but lacked some of the “meat” in the middle part of the power that we liked so much with the standard coupler setting (that comes with the 2016 model). The trade off simply wasn’t worth it for us on this day. The “rich” coupler mellowed the bottom end too much, but pulled extremely well on top end. We could see the “rich” coupler being good for a really fast moto track or an off-road type setting.
Suspension: The new KYB suspension feels more balanced out on the track. For those who have never been to Pala Raceway it’s a sandy-based soil with huge jumps. Although the track didn’t get beat up that much (due to only having eight riders on the track), we did get a feel for the action of the suspension. The KYB air fork actually moves (unlike most air forks today)! The few bumps that were on the track were a good indicator of how well the fork moves on the top of the stroke (or light bump). Accelerating out of corners, deflection was minimal and the action of the fork was progressive through the mid stroke as well. For our faster, slightly heavier tester (Associate Editor Kris Keefer, 170 pounds), one to two pounds of air adjustment were played with in the fork. This helped keep the fork up in its stroke on steeper jump faces around the track. We played with high and low speed compression (on the fork) before we tried messing around with air pressures but in the end going up in air did the trick. We were timid at first to try this because we didn’t want to lose the front-end grip in corners (due to the fork being higher in the stroke) but it didn’t take away from Suzuki’s great front-end feeling. The shock sag was ran at 105mm and felt firm, but had comfort on the small chop that was available for us to test on. On slap down landings the rear of the bike didn’t bottom violently as we fell out of the sky on some of the bigger jumps at Pala. Overall, the 2016 RM-Z250 is more balanced (than the 2015), once we added a couple pounds of air in the front fork, for the jump filled track that we tested on.
Chassis: The new RM-Z250 frame definitely has added comfort built in compared to its older sibling. While the 2015 seemed to have more of a rigid feeling frame character the 2016 flexes underneath you and provides better traction when the track dries out. You can feel the flexing characteristics especially when landing from jumps. There is more of a “cushiony” feeling versus a solid hard feeling to your feet. What is even better about the updated frame on the Suzuki is that it still can corner very easily. The 2016 RM-Z250 lays into a rut incredibly well and will stick around the whole corner. There is no vague front end feeling through mid corner and even with the sub par feeling of the Dunlop MX52 front tire, the yellow machine sticks when you ask it to. The RM-Z is still a front-end biased chassis as it is sometimes hard to rear end steer the machine through flat, blown out corners. Although we don’t know if the frame is more narrow than last year’s, it feels that way around the track. Quick line changes are extremely easy to make whether on or off the throttle.
Extras: We played with the standard, A, and B modes of Suzuki’s Holeshot Assist Control (S-HAC). In “A” mode we could get out of the hard packed starting area slightly smoother without wheeling 10-15 feet out of the gate. If your starting technique is good you will want “B” mode on every dirt gate drop you take. Four out of five times we tested in “B” mode, we got out of the gate a half a bike length better than when we tested it against another rider that was in the standard mode.
It’s nice to see not a few, but several changes to the Suzuki RM-Z250, as the model has been lacking in development for quite some time. The 2016 Suzuki RM-Z250 is a better handling and faster machine, and that is what it exactly needs if wants to keep up with Yamaha’s 250F. How will it stack up? We don’t know yet, but you can count on seeing more in depth test updates on the 2016 RM-Z250 at dirtrider.com. Also don’t forget to be on the lookout for the 2016 250 MX Shootout coming in the pages of the Feb/Mar issue!