Just reading an article on the new 2015 WR250F.
It shows some specs in it for the little engine, one which raised a smile is the throttle body size (44mm).
I remember being told after removing the butterfly in my original post that the 449 engine wouldn't take full throttle as the 46mm port would be too big.
Obviously the bikes run fine without the second flap & the little WR250 is running a 44mm body, only 2mm less dia, but 200cc smaller engine.
(Very keen to try this bike btw)
Gotta love EFI if it is well sorted.
PRODUCT CENTRE
17 OCT 2014
Bike: 2015 Yamaha WR250F
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Section: Bikes
Post: Alex Gobert
Complete 2015 model Yamaha WR250F information.
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Source: Yamaha.
The 2015 Yamaha WR250F, officially unveiled locally on Friday, 17 October, during a presentation at the Australian Motorcycle Grand Prix, is heavily-based upon the championship-winning YZ250F motocross model.
It features the latest revolutionary rearward-slanted, fuel injected, 249cc, DOHC four-stroke engine with four titanium valves, bilateral beam frame, industry-leading KYB SSS suspension, electric starter, aluminum side stand, 18-inch wheel, wide ratio transmission and a sixth gear.
The 2015 WR250F is the perfect bike to tackle the toughest enduros on the planet; the suspension, fuel injection, clutch and engine character have all been carefully chosen to provide the best experience when the riding gets tight and twisty.
The WR250F comes with all the standard features needed to compete and win in enduro events, including a headlight, taillight, skid plate electric radiator fan and enduro computer.
Feature overview:
– All-New for 2015 with a revolutionary rearward-slanted 250cc, liquid-cooled, DOHC four-stroke with four titanium valves based on the 2015 YZ250F, with an added sixth gear and wide ratio transmission, among other modifications, make it perfect for enduro competition.
– Nearly the same bilateral beam frame that is found on the championship winning YZ250F is used on the WR250F. It places the engine and fuel tank close to the center mass of the bike for extremely light and nimble handling character.
– A Keihin 44mm throttle body fuel injection system is tuned for enduro riding ensures smooth throttle response and easy starting in nearly all conditions. Plus the electric start button reduces rider fatigue.