For 2015 the host of engine changes witnessed for the 2014 model, which included a new connecting-rod material and design matched to a new piston, featuring 'bridged box' construction with altered material densities in high stress areas giving less deflection at high rpm's for greater performance and durability, matched to a revised DLC coated gudgeon pin, a new clutch basket with a friction reducing coating and new clutch plates, a new oil pump with modifications to the oil galleries, revised ECU settings with mapping changes to suit the new engine characteristics and a new wiring loom, continue on to the 2015 model but with some alterations in key areas. After having another 12 months of testing at the highest levels of competition in the MX and Enduro World Championships the latest updates to the 250Fi engines come from development of the TM Factory Racing Teams. The 2015 engine will continue with the well proven 2014 alterations but now receives a new inlet ducting system, throttle body and air funnel into the venturi to improve air feed for power maximisation, a new oil filter arrangement for greater oil flow, a new exhaust system allowing for greater performance and smoother power delivery all matched to revised ECU settings. These changes maximise power output and efficiency increasing power and torque for a large part of the rev range and these profiles are different for both MX and Enduro variants too. Both the MX and Enduro engines have unique pistons and head profile variants to give the performance required for each discipline, on the MX engine the engine 'profile' is designed to suit the 'harsher' nature of Motocross, whilst the Enduro engine retains a more 'relaxed' profile to give a smother, broader power output better suited to the required conditions found in Enduro competition events.
Chassis changes include new chassis geometry with modified front fork rake for increase turn-in, stability and all round 'lighter' handling characteristics a longer swing-arm for better bike balance and weight distribution, a new rear shock length (8mm) and revised linkage for better progression and traction in all conditions working with revised suspension settings. The big change in the chassis department is the adoption of the new component layout designed to optimise weight balance, handling and engine performance, this features an intake system over the engine and the positioning of the fuel tank under the seat for a much more balanced machine and lower centre of gravity. Also featuring is a new rear wheel spindle diameter for greater strength and less deflection of the swing-arm, a new triple clamp arrangement with less offset to improve rideabilty of the new chassis layout and weight transferal system, a new air filter for better efficiency of the new intake system and a new plastic design in a fresh and aggressive style featuring a new seat arrangement and fresh graphics in an Italian theme.
TM Racing 'Factory' rear shock absorber, Kayaba 48mm forks, billet machined aluminium hubs laced to anodised Excel rims, billet machined aluminium triple clamp with damped handlebar mountings, oversize taper bars, oversize 'wave' braking discs and a switchable twin map ignition system.
Single cylinder 4 stroke water cooled engine with twin camshafts driving 4 independant finger followers operating titanium valves, dry sump with twin rotor oil pump for recovery and distribution, downdraught ''baterry-less'' electronic fuel injection with 44mm throttle body, billet connecting rod with bridged-box forged piston and DLC coated gudgeon pin, Centre drip feed clutch plate system and a HGS 'bomb' type exhaust system, electric starter with conventional kick.
Bore and Stroke: 77X53,6 Displacement: 249,46 Compression ratio: N.A. Horse power: N.A. Timing system: DOHC with finger follower and 4 Titanium Valves Lubrification: Dry sump with double rotor pump Fuelling: Battery-less Electronic Fuel Injection with 44mm throttle body Fuel: Super-unleaded Ignition: Kokusan generator, Microtec Electronic Clutch: Multiuple-disk in oil-bath with hydaulic control Gear: 6 gears Cooler System: Coolant liquid with pump Starting: Electric start and kick start Frame: Perimetral aluminium section Front fork: Marzocchi USD/Kayaba USD Rear shock: TM Racing Front tyre: 90/90X21 Rear tyre: 120/90X18 Front brake: Braking wave disk 270 mm, with Nissin pump and Brembo caliper Rear brake: Braking wave disk 245 mm. With Nissin pump and caliper Tank: Plastic 8,2 litres