2018 Yamaha YZ250F | Review

By Jeff McConkey

The 2018 Yamaha YZ250F.

I first rode the 2018 Yamaha YZ250F at the YZ450F media launch at Motopark in Chatsworth, Ontario. My first impression, it was very easy to ride and go fast on right away. I didn’t adjust the bars or levers and I still felt right at home. The YZ had great power all of the way through the gears and never seemed to fall off.

I had the opportunity to race this same bike on the motocross track as well as an enduro. As much as I loved it on the moto track, I was equally impressed at how well it performed in the woods. I was able to lug the bike a gear high through the woods and it still had enough ‘grunt’ to get me out of trouble and get the front end up when needed. I found that the bike turned really well in all situations and it never really tried to spike me or stand me up in the tight corners.

Jeff rode the 2018 Yamaha YZ250F at the OCMC 6-Hour Enduro. | Steve Mohr photo

The suspension was top notch right out of the box. It handled the chop and rough breaking bumps with ease and really sat in the rut through the corners. I never really felt like it wanted to buck or load up on me and I actually looked forward to the rough stuff, instead of avoiding it like normal.

The 2018 model felt thinner to me in the rad shrouds, and the seat and tank allowed me to move wherever I needed to be without any restriction. I enjoyed the fit and finish of the machine, and thought it looked great.

Final Impression: This is a great bike right out of the box. I was very impressed with how fast it was, and how well it handled all types of terrain with ease. The 2018 YZ250F could be a force on the local track and enduro track by just throwing on a set of numbers and going a few clicks in either direction with the suspension. We all know that these 250f  Yamahas are bulletproof, so do yourself a favour and head to your local Yamaha dealership and get yourself one.

Key Features

  • Revolutionary reversed engine design with front mounted FI system & rear exiting exhaust
  • Mass centralizing rearward-slanted-cylinder helps keeps weight centred in the chassis
  • “Battery-less” 44mm throttle body FI & easy access air box
  • Compact aluminum Bilateral Beam frame & aluminum swingarm
  • Industry-leading, fully adjustable KYB® “SSS” fork & Monocross rear suspension
  • 270 mm front & 245 mm rear disc brakes
  • Adjustable, tapered aluminum handlebar
  • GYTR® Power Tuner Ready

ENGINE

  • Design goals for the fuel injected YZ250F are a balance of easy cornering & a lightweight feeling, thanks to excellent mass centralization. The fuel injected engine features a wide, controllable power band that sets the standard in the 250 class.
  • “Reversed” liquid-cooled, 250cc, DOHC, 4-valve (titanium), single with fuel injection.
    • excellent “ride ability & controllability”
    • broad power from low rpms right through to high rpm with excellent power characteristics
  • Rearward slanted, reversed cylinder design.
    • rearward slant moves a significant amount of rotating weight toward the centre of the chassis, centralizing mass for light, agile handling
  • “Reversed” engine design (FI system is front mounted, exhaust exits from rear of cylinder).
    • FI throttle body & air box are front mounted, providing a straight intake path
    • straight shot intake path provides optimum fuel / air / exhaust flow for excellent power
    • front mounted intake keeps fuel cooler since engine heat has less effect on incoming fuel (cooler fuel is more dense & increases power)
    • design also helps centralize mass for light, agile handling
  • 4-valve cylinder head features a 13.5:1 compression ratio.
    • 4-valve design offers optimum flow & excellent power
    • compact combustion chamber provides optimum combustion speed while also reducing heat & power losses
  • Lightweight titanium valves.
    • 31 mm titanium intake & 25 mm titanium exhaust valves with load reduced valve springs
    • load reduced valve springs reduce internal power losses
    • titanium valves reduce weight & improve performance… titanium valves are 40 to 45 % lighter than steel valves
    • reduced valve weight improves valve train reliability & longevity
    • reduced reciprocating weight allows for a higher rpm limit & better control of the valve
  • 5-speed transmission utilizes a 2-bar, floating shift guide system & a 14 mm shift shaft.
    • gears ratios are matched to engine power
    • floating shift guide system provides smooth, positive shifts
    • 14 mm shift shaft provides good durability in the event of a crash
    •  44mm Keihin throttle body fuel injection system.
    • 10-hole injector maximizes fuel atomization for more complete combustion
    • FI benefits include automatic adjustments to insure the optimum fuel — air ratio regardless of outside air temperature & altitude
    • other benefits include excellent starting & instant throttle response
    • cold start knob also doubles as an idle adjuster

John Bayliss gives the “purplish white” 250F some love at the end of the day. | Bigwave photo

CHASSIS/SUSPENSION

  • Compact “Bilateral Beam” aluminum frame.
    • frame & engine designs centralize mass for exceptional handling & maneuverability
    • frame offers an optimum rigidity balance between strength, rigidity & tuned flex, plus excellent shock absorbing qualities
    • frame design provides excellent “rider — machine communication” (a.k.a. feedback)
    • key goal of this chassis design is faster & easier cornering … one of the keys to winning races
  • Lightweight, tapered aluminum swingarm.
    • lightweight design reduces unsprung weight for excellent suspension performance
    • excellent rear wheel traction & control
    • large 25 mm rear axle

  • 48mm, adjustable, inverted, Kayaba “SSS” cartridge fork offers 310mm (12.2″) of wheel travel.
    • front fork adjustments include: 20-way compression damping & 20-way rebound damping
    • inner tubes feature a special friction reducing coating for reduced stiction
    • 22 mm front axle
    • optional fork springs are available through Genuine Yamaha parts
  • Monocross link rear suspension with 315 mm (12.4″) of wheel travel.
    • features a fully adjustable KYB piggyback shock
    • separate adjusters for high- and low-speed compression damping
    • shock is in-line with the center axis of the frame for excellent control
    • shock adjustments include: threaded spring preload, low-speed compression damping, high speed compression damping & rebound damping
  • 270 mm floating front “wave-style” disc & compact Nissin twin piston caliper.
    • wave disc design reduces weight & improves cooling (wave design offer more surface area for better cooling)
    • “shorty style” adjustable front brake lever can be adjusted to fit various hand sizes
    • high friction brake pads
    • excellent braking performance
  • 245 mm rear disc brake uses a “wave-style” disc & single piston Nissin caliper & master cylinder.
    • wave disc design reduces weight & improves cooling (wave design offer more surface area for better cooling)
    • rear caliper & lower portion of the wave style disc are protected by heavy duty plastic protectors