2017–2020 · Naked Bike · Buyer's Guide
The Triple That Bites Early
The RN43 is built around the CP3, an 847 cc inline triple with a 120-degree crank that gives the bike its voice. The numbers read 115 hp and 65 lb-ft, but the real story is the fat middle of the rev range that starts shoving from around 3,000 rpm. A compact aluminum frame keeps the whole machine small around you, and the equipment list is more serious than the bike's reputation suggests: adjustable suspension front and rear, a slipper clutch, an up-only quickshifter, ABS, traction control and ride modes. In its class it sits firmly on the wild side of the naked bracket.
On the road it feels smaller and lighter than the 425 lb wet figure, and the 32.3 in seat puts you high enough to read traffic without towering over it. It holds up well mechanically, and the parts supply means a used one can be brought exactly where you want it without much money. The honest caveat: this generation wants an owner who stays on top of it. The throttle bodies drift out of sync, the fueling low down is coarse, and neither problem quietly fixes itself. Keep up with the servicing and it stays charming. Neglect it and the charm turns into irritation.
Spec sheets don't ride bikes, but they set the baseline.
| Power | 115 hp (85 kW) @ 10,000 rpm |
|---|---|
| Torque | 65 lb-ft (88 Nm) @ 8,500 rpm |
| Displacement | 847 cc |
| Engine | Inline-three |
| Cooling | Liquid-cooled |
| Gearbox | 6-speed |
| Final drive | Chain |
| Front tire | 120/70-17 |
| Rear tire | 180/55-17 |
| Wheelbase | 56.7 in (1440 mm) |
| Seat height | 32.3 in (820 mm) |
| Wet weight | 425 lb (193 kg) |
| Fuel capacity | 3.7 gal (14 L) |
| Top speed | 148 mph (238 km/h) |
| Fuel economy | 47 mpg (US) |
Equipment check
Chassis
Drivetrain
Lighting
Safety
Roll away and the first thing that registers is the noise. The triple carries an intake growl over a hard exhaust bark, and there is a light mechanical rattle around 3,000 to 3,500 rpm from the cam chain tensioner that sounds worse than it is. The riding position is upright and roomy, wide bars, knees folded without being cramped, and with nothing in front of you the wind goes straight into your chest. At 60 mph on a back road that pressure is doing you a favor. It makes ordinary speeds feel like an event and keeps your license out of trouble. Stretch it out on the interstate and the grips start buzzing, enough that you go hunting for heavier bar ends. With 3.7 gal and 47 mpg, you are stopping for fuel before you are tired of sitting on it.
This part of the guide is the community talking, not me. It is what two decades of listening adds up to: conversations at rallies and gas stops, owners comparing notes at meets, and the messages riders send in after a season with the bike. Put enough of it side by side and the RN43 crowd lands in a consistent place. The agreement is about how the bike goes and how it turns, and the arguments are about setup rather than about the machine itself.
Ask a group of owners what keeps them on this bike and the answer comes back fast, and it is almost always the same pair. The triple gets described in terms riders do not reach for with anything else in the class. They talk about a pulse rather than a power figure, about drive that is there low in the rev range and stays with them all the way to the top, and about acceleration they call addictive without much embarrassment. Then comes the steering. Owners say it changes direction like a smaller machine, that the bars give them all the leverage they need, and that very little input is required to swap from one side of the road to the other. Riders who came off other bikes in the segment bring this up unprompted.
The riders with the most distance behind them are the calmest voices in the conversation. Owners past 25,000 miles (40,000 km) describe engines that have simply not given them trouble, and the ones who have had the valves inspected at that kind of mileage report the internals looking exactly as they should. When owners rate their own bikes among themselves, this is the area that comes out on top. It generates the least back and forth of anything in the ownership story.
The remaining complaints get discussed as jobs rather than as faults. Heavier riders keep saying the standard suspension runs short of support under their weight, sprung softer than they want even though they acknowledge it moved on from the generation before. The SP, with its Ohlins rear shock and stiffer fork springs, is the version that gets named as the answer. The other running conversation is the fueling low down, where the abruptness is sharp enough that riders point each other toward an ECU flash rather than adapting around it. Both come up as things owners sort out, not things they walk away from.
Lower handlebar holder may loosen due to paint/adhesive defect
The lower handlebar holder was painted improperly during manufacturing, and the stud bolt threads had inadequate thread-locking agent. External impacts can damage paint on the bottom of the holder; over time, paint wears off from vibration, creating clearance that allows the stud bolt to loosen. If the stud fails, loss of vehicle control can result.
Throttle body de-synchronization causing rough idle
The three throttle bodies go out of sync within a few thousand miles (a few thousand km), leading to rough idle, stalling (especially at low speeds), and poor low-RPM response. Idle Speed Control (ISC) may need resetting after synchronization. Some cases traced to Throttle Position Sensor (TPS) degradation or Acceleration Position Sensor (APS) issues.
Quick Shifter System intermittent failure
The OEM quickshifter can stop working intermittently. Common cause is an internal Alps Alpine micro-switch failure. Symptoms include QS light on but no function, intermittent ignition cut during shifts, and hard/stuck upshifts. Cold engine operation worsens symptoms. Yamaha dealers have confirmed replacing multiple faulty units under warranty.
Front brake disc pulsation / warping
Front brake discs develop pulsation felt through the lever during braking. The floating disc design may not fully prevent warping under hard or normal use. Disc replacement or aftermarket rotors are the definitive cure.
Snatchy ride-by-wire throttle response at low RPM
The electronic throttle is abrupt and jerky between 2,500–4,000 RPM, creating a push/pull sensation when rolling on from idle or cruising at low speeds. This is an ECU mapping issue inherent to the CP3 engine across all generations, though the 2017 D-Mode B setting helps. The mixture is set lean for Euro 4 compliance, and deceleration fuel cut causes jerkiness when reaccelerating. An ECU flash or tune (e.g., 2WheelDynoWorks, Woolich Racing) is the common fix.
Cam chain tensioner rattle at low RPM
The non-hydraulic "half nut" ratchet-type cam chain tensioner can produce a rattling/ticking noise, most noticeable at 3,000–3,500 RPM. Yamaha released a revised part number (S1 vs. S2 versions). The rattle can return after dealer adjustment. Some owners upgrade to a manual cam chain tensioner (e.g., APE brand). Primarily documented on RN29 models but also confirmed on 2017–2018 RN43 models with the same engine.
Excessive handlebar vibration during sustained high-speed riding
Noticeable buzzing/micro-vibration through the handlebars, particularly during sustained highway riding. Causes hand numbness within 5–10 minutes at certain RPM ranges. OEM bar-end weights are light (~1 oz (~30 g)); heavier aftermarket bar ends (~8 oz (~230 g) per side) help but don't fully eliminate. Engine mount and handlebar mount bolt torque should be checked.
Seat seams leak water during rain riding
Seat seams allow water to seep in during rain. The seat foam absorbs water, making it uncomfortable and slow to dry.
Premature corrosion on multiple components
Multiple components prone to premature corrosion: bar-end Allen key holes rust quickly, rear shock spring corrodes, front disc bolts rust, exhaust headers show surface corrosion and discoloration, general bolt corrosion. Matte paint finish is very thin, scratches easily. Some bolts showed rust at less than 1,000 miles on new bikes. Pressure washing and salt exposure accelerate corrosion significantly.
Where this Yamaha MT-09 pulls ahead of — or falls behind — its rivals on the numbers, and the typical bike in its class on character.
Power
Torque
Displacement
Wet weight
Seat height
Forget spec-sheet bragging. Here's who the MT-09 is actually built for.
Angeles Crest is exactly this bike's habitat. Light steering, deep lean angle and a triple that punches out of second-gear corners make it a serious Sunday tool, once you learn its low-rpm throttle.
Made for Angeles Crest Highway · Coronado Trail / US 191 · Highway 1 / Big Sur
For Dragon and Cherohala work, the low-end drive and easy handling let you concentrate on lines instead of wrestling the bike. The wind pressure also keeps your speeds honest on patrolled roads.
Made for Back of the Dragon · Blue Ridge Parkway · Cherohala Skyway
It rewards clean inputs and gives you plenty of lean angle, but the suspension and brakes are set up for the road. Take it as a fast, playful backroad machine rather than a dedicated hard-use one.
Made for Barber Motorsports Park · WeatherTech Raceway Laguna Seca · Circuit of the Americas
If you're cross-shopping the older generation, here's what changed.
Previous generation · 2014–2016
Hooligan Engine, Japanese Precision
Compare to the previous model →If this one isn't quite the fit, these are the bikes worth riding back-to-back against it.
Any price note compares both bikes at the same age — the youngest age both have on the used market — against this Yamaha MT-09. “cheaper/pricier” is what that bike costs second-hand, not how worn it is.
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Italian Fire, Limited Edition
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Competitor · 2018–2021
Race Engine, Zero Drama
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Competitor · 2017–2019
Triple Soul, Corner Ready
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Same Platform · 2018–2020
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~$200 cheaper used than this bike at 6 yr