It’s Here: The All-New 2018 Yamaha YZ450F
There have been a few bikes for 2018 released thus far and it’s kind of been a buzzkill, especially in the 450F department and Suzuki has yet to release official info on their new mount. Honda might have a radical 250F but that is still speculation.
The big news for Yamaha is the all-new YZ450F. From our understanding, there are very few parts that cross over from the previous model, except for some components such as brakes—even the handlebar is new.
First off, you will never have to kick your YZ450F over ever again, unless it pisses you off. Yes, KTM finally made the big four start to fold and now offer full-time electric start 450cc motocross bikes. And since the YZ450F is such a popular ride for local track riders and vets, they are going to be elated, we are! The old adage of if you can start it you can ride it no longer holds water, even granny can hit the magic little button and fire this beast.
That is only one of the highlights to this machine. The chassis and the engine are all new as well. The 2018 looks similar with its reverse cylinder design but that is pretty much where it stops. However, it does not appear the Yamaha engineers tossed the baby out with the bath water, yet rather took an already solid motocrosser and did a pretty extensive renovation and only left a few small walls standing.
The chassis has always been known for being a little wide and big feeling so that was addressed by narrowing the chassis by 16mm in the tank area and 18mm in the seat. The handlebar position is now 5mm higher and the seat pocket is 8mm lower and in the rear it’s 19mm lower. Foot peg position in relation to the frame remains the same.
The frame is a new design and gone are the hydro-formed tank rails/twin-spars and now there are less complex extruded aluminum units. Yamaha said they did a lot of testing with the tension pipe location (or cross member from the down tube to the twin-spar). It’s also now an extrusion over forging. The steering head is actually 6mm longer with an overall wheelbase increase of 5mm over 2017. The triple clamp offset is now 22mm compared to 25mm, this also changes the overall trail from 118mm to 121mm. Yamaha also says the overall frame has increased rigidity of 25% vertically, 9% horizontally, and 15% torsional. The stiffer chassis is said to help overall handling and turning but because of the new frame design, tension pipe location, and rearward engine mount location, the changes have actually created more impact absorption because overall flex is now spread over a greater distance giving you the best of both worlds.
Because of the new bodywork, the YZ450F also has a new, very easy-to-access tool-less air filter. The cover now only uses one Dzus fastener compared to three. There is also more volume in the airbox itself under the filter by 29%.
The engine looks very similar but is very much new. The cases were redesigned to house a very compact electric start motor that draws less power and has more cranking performance than the current setup on the YZ and WR450s. A 1.5-pound lithium-ion battery under the seat powers the starter.
The cylinder head has a straighter intake track and the cam profiles have been altered to increase the lift on the intake side by .5mm and .4mm in the exhaust. The intake cam also opens earlier than before.
The piston is a new bridge box design and is now 6 grams lighter with a DLC-coated piston pin. The spark plug is longer for a better burn and the ECU has new settings. The actual cylinder is also 2 degrees more vertical compared to 2017. Engine mount material has also gone from steel to aluminum as well.
The crank has been redesigned with more inertia with a new balance ratio. The overall inertia remains the same as 2017 because they were able to decrease the inertia on the flywheel since power generation is less of a factor due to the battery and now there is less rotational resistance.
The transmission has the same gear ratios yet the gears themselves (2nd, 3rd, 4th) have been beefed up and are now 1mm wider. The clutch pressure plate has been redesigned to offer a tad more flex in the center for more feel, and the steel clutch plates now have surface grinding process on both sides compared to only one side.
Another big change is the throttle body. Yamaha has made the switch to a 44mm Mikuni unit with a 12-hole injector. A nice new feature is that the cold start plunger will automatically close by 
shutting the throttle all the way off or blipping the throttle. The exhaust system has been altered with a longer header pipe, smaller diameter mid pipe, and now the muffler lower mount is rubber mounted. Other changes include radiator angle and position. Fenders have a new style as do the number plates. Rims now come in blue on the standard model and black on the option model and are lighter than before. Overall fuel capacity has also been decreased from 1.9 to 1.6 gallons, yet Yamaha says the bike will do a 40-minute moto. Grand Prix riders will have to seek other solutions.
Yamaha has also broken ground with a wireless tuner app. This means that you can tune your bike at the track with your smartphone using onboard WiFi. Each sender/receiver has its own specific code to log in to a specific motorcycle. The app is actually more detailed than the current GYTR handheld tuner. The tuning grid is now 4 rows up and 4 rows down for both ignition and fuel. The grids can also be configured to isolate areas as well. Fuel has a 14% plus or minus range and ignition -9% regarding and 4% advance. There is also a race log for specific tracks or conditions, monitor mode, and maintenance mode with diagnostic code reader. This system is included with every 2018 YZ450F.
Yamaha is now calling the SSS Kayaba suspension Next Generation. The fork changes include a larger piston from 24 to 25mm, mid-speed valve has a new leaf-spring design, and the pressure piston has a new shape and an added hole for better feel. The shock has a 30cc increase in the sub-tank volume and the rear spring is lighter with fewer coils with a new material. The spring rate has also been increased to 58 N/mm from 56.
Overall weight was not openly discussed during the press launch yet Yamaha R&D guys said the overall weight should be the same or slightly lighter on the full production bikes. The 2018 YZ450F will be offered in two colors for a retail price of $9,199 and should be available late July or early August.
So what does this all mean? It means we can’t wait to ride one. The 2018 is a new motorcycle but it appears Yamaha continued down the same road that made the current YZ450F very popular. There are a lot of changes but nothing too radical or in a different direction. The electric start is awesome. It does not appear to have gained any weight and the chassis has been slimmed down (one of the biggest complaints to the current model). If Yamaha puts more power to the ground it will only be another win-win. We have always sworn by the GYTR tuner as a must-have and now Yamaha offers a smartphone app tuner for every customer. Kudos to Yamaha for being the first to break this barrier.
And we imagine that this new chassis will be the base for models in the future like the YZ250F and the off-road line in years to come. Look for a DBT first-impression and full test when the bikes are released.
