2015 Yamaha YZ 2-Stroke Models

2015 Yamaha YZ 2-Stroke Models

The 2-stroke is back…
Giving off road riders more choice
Yamaha continues to power ahead in the off road competition world with a line-up of revitalised YZ 2-stroke models that complement the company’s strong motocross model range. Coming just 12 months after Yamaha released the all-new YZ450F and YZ250F 4-strokes, the launch of the new YZ 2-stroke models underlines our total commitment to every sector of the motocross market.

2015 YZ 2-strokes: New looks with new technology For 2015 the Yamaha YZ85, YZ125 and YZ250 2-stroke models benefit from a number of significant changes that are designed to deliver increased performance on the track. In addition to the series of technical improvements, every model features dynamic new bodywork and bold new graphics that echo the modern style of the latest YZ-F models.

Yamaha and 2-strokes: An ongoing relationship
Yamaha and 2-stroke technology go back a very long way. The company’s first ever production bike was a 2-stroke and in 1973 Yamaha won the first of its 26 FIM World MX Championship titles on a YZ250 2-stroke.
The off road world changed dramatically when Yamaha developed the first generation of YZ-F 4-stroke bikes in the late 1990s, but our YZ 2-stroke models continue to be an integral part of the company’s comprehensive dirt bike line up. The current range of YZ models has attracted a devoted following amongst riders who appreciate the light handing as well as the explosive power characteristics and ease of maintenance associated with 2-stroke ownership. This is also underlined by race wins in all of the 2-stroke classes at European level in 2014, with Yamaha victories in EMX85,
EMX125 and the newly established EMX300 class.

Yamaha believe that the YZ 2-stroke models form an integral and important part of the overall off road range. A significant number of off road riders value the special character and specific qualities of the 2- stroke and for these customers the YZ range has been revitalised and refreshed for the 2015 model year.

Yamaha YZ85 – Ready for the new generation
Over the years, countless riders have started out on the YZ85, with many of them going on to achieve off road success at national and international level. Just like the YZ125 and YZ250 2-strokes, the YZ85 offers a combination of highly responsive engine performance with light and agile handling, making it a leading choice among younger riders who are taking the very first steps in their racing career. Currently, Yamaha mounted riders occupy the first two positions in the highly competitive South West region of the European EMX85 Championship.

2015 YZ85
The 2015 YZ85 gets a total body makeover and is equipped with a new front fender, air scoops, side covers and seat cover to give a lean and professional image. The new ‘Speed Block’ graphics and a bold new YZ logo emphasise the contemporary lines of the latest model, and bring the 2015 YZ85’s looks in line with the rest of the YZ and YZ-F family.
In addition to the refreshed YZ-family image, the 2015 YZ85 also benefits from technical changes to the compact and lightweight, liquid-cooled power plant. The proven 85cc 2-stroke engine is already known for its strong yet un-intimidating power characteristics and for 2015 Yamaha’s engineers have made detailed changes to the intake and exhaust port timing.
A modified cylinder gives increased performance together with improved usability, further reinforcing the widely acclaimed characteristics that have helped to make the YZ85 such a successful and popular race bike with new riders. The 2015 model is also equipped with an easy to use clutch adjuster mechanism, allowing riders to set the clutch lever play to suit their own requirements.

YZ85 Technical Highlights

• Newly designed lean and contemporary bodywork
• New graphics with harmonised YZ logo and ‘Speed Block’
• Revised intake and exhaust timing for greater usability and performance
• Handlebar-mounted clutch adjuster

Existing highlights:

• 85cc liquid cooled 2-stroke engine
• 6-speed transmission
• 28mm carburettor with good throttle response
• Upside down front forks with 275mm wheel travel
• Lightweight tubular semi-double cradle frame with excellent rigidity balance
• Detachable subframe
• Long swingarm

Yamaha YZ125 – For tomorrow’s pro-riders
With its low weight and free-revving 125cc, 2-stroke engine, the Yamaha YZ125 is an ideal race bike for teenage riders who are serious about making a name for themselves. Along with the YZ85 and YZ250 2-strokes and the YZ-F 4-strokes, the YZ125 forms an integral part of the Yamaha motocross line up and the 125 model is aimed primarily at riders between 15 and 19 years of age.
Despite the fact that the spotlight has undoubtedly been focused on the 4- stroke scene in recent years, the YZ125 continues to appeal to the significant number of riders who regard the 125cc 2-stroke as one of the best ways to develop their racing skills before graduating to the pro class on board a YZ250F or YZ450F.
After race wins and a 2nd overall position in the 2013 EMX 125 European Championship, the current YZ125 is once again showing its race winning ability in the 2014 series. After the first 4 (of 7) rounds in this highly competitive championship, Yamaha have two bikes in the top four standings, demonstrating that the YZ125 can race and win at the highest level in one of the world’s most prestigious 2-stroke series.

2015 YZ125
For the 2015 model year the YZ125 2-stroke is completely revitalised with a range of stylistic changes that are designed to deliver a lean and modern new image – while important technical updates deliver refined handling characteristics.
The redesigned bodywork and new graphics project a sharp and lightweight appearance that complements the look of the latest generation  of YZ-F 4-strokes. The new front and rear fenders, number plate, air scoops, airbox/side covers, fork protectors and seat cover give a thoroughly up to the minute ‘factory-bike’ feel – and the bold new ‘Speed Block’ graphics and big YZ logo on the tank and scoops accentuate the dynamic and aggressive design image pioneered by the recent YZs.
Significant improvements have been made to the front and rear suspension for 2015 and the new systems are now the same as those used on the latest YZ-F 4-stroke models. The 48mm upside down front forks and the link-type Monocross rear suspension run with YZ125-specific settings in order to ensure optimum traction and good terrain following characteristics. Both the front and rear systems are fully adjustable to suit varied track conditions and different rider weights and riding styles.

For quick and easy adjustability the 2015 model is equipped with the latest YZ-F 4-stroke type handlebar-mounted clutch adjuster mechanism, and the YZ125 is also fitted with wider YZ-F type footrests that give improved feel and comfort – especially on jumps and whoops. Completing the 2015 package are the latest pattern Dunlop tyres, as well as a YZ-F style rear sprocket, rear disc guard and rear caliper guard.

YRRD Racing Kit
Yamaha offer special kit parts for the YZ125 that have been developed in association with the highly respected Italian company YRRD (Yamaha Rinaldi R&D). Run by former World Champion Michele Rinaldi – who is the manager of the Yamaha Factory Racing motocross team – YRRD has developed a professional quality race kit for the 2015 YZ125 that features a wide range of performance boosting parts.

The kit includes:

• Sand-cast cylinder head
• Special piston assembly
• High performance CDI unit
• High inertia rotor assembly
• Special exhaust pipe
• Carbon fibre reed valve
• Titanium silencer
• Carburettor setting parts
• Optional modified cylinder and YPVS

Full information at www.yamaha-racingparts.com

YZ125 Technical Highlights

• YZ-F type 48mm front forks with separate air/oil system
• YZ-F type link-type Monocross rear suspension
• YZ-F type rear sprocket, rear disc guard and rear caliper
• YZ 2-stroke specific suspension settings
• Newly designed lean and contemporary bodywork
• New graphics with harmonized YZ logo and ‘Speed Block’
• YZ-F type handlebar mounted clutch adjuster
• YZ-F type wide footrests
• Latest pattern Dunlop tyres

Existing highlights:

• 125cc liquid cooled 2-stroke engine
• YPVS (Yamaha Power Valve System)
• Close ratio 6-speed transmission
• 38mm carburettor with good throttle response
• Semi-double cradle aluminium frame
• Special YRRD kit parts available

Yamaha YZ250 – Enduring appeal
Featuring a lightweight aluminium chassis and powered by responsive 2- stroke engine, the Yamaha YZ250 motocross bike has established a reputation for its highly competitive performance that ensures a thrilling and rewarding ride. The YZ250 has recently demonstrated its winning ability in the newly established EMX300 Championship for 2-strokes, showing that this proven design still has what it takes to compete and win at a high level.

This legendary model is very popular with MX racers, fun riders and FMX athletes who appreciate its strong all round performance, as well as its high levels of reliability. In addition to these qualities, the mechanical simplicity of the 250cc 2-stroke liquid-cooled engine ensures easy routine maintenance. It is also relatively straightforward and inexpensive to tune using widely available aftermarket parts.

Recently the YZ250 has come under the spotlight as a number of leading dirt bike magazines have ‘re-discovered’ its enduring appeal. Many riders appreciate the low weight and explosive power of the YZ250, which – together with the bike’s easy to maintain engine technology – make it popular with a broad spectrum of competitors. In addition, the YZ250 is also highly appreciated by the many riders who grew up on 2-strokes, and who love everything about them.

2015 YZ250
The 2015 YZ250 2-stroke has undergone the same visual transformation and technical upgrades as the YZ125, including the fitment of the latest YZ-F 4-stroke front and rear suspension systems, as well as contemporary new bodywork and bold new graphics. The new YZ250 is also equipped with a handlebar mounted clutch adjuster, as well as wider footrests and the latest pattern Dunlop tyres.

Please refer to the YZ125 section for detailed information about the new suspension and bodywork.

YZ250 Technical Highlights

• YZ-F type 48mm front forks with separate air/oil system
• YZ-F type link-type Monocross rear suspension
• YZ 2-stroke specific suspension settings
• YZ-F type rear sprocket, rear disc guard and rear caliper
• Newly designed lean and contemporary bodywork
• New graphics with harmonised YZ logo and ‘Speed Block’
• YZ-F type handlebar mounted clutch adjuster
• YZ-F type wide footrests
• Latest pattern Dunlop tyres

Existing highlights:

• 250cc liquid cooled 2-stroke engine
• YPVS (Yamaha Power Valve System)
• Close ratio 5-speed transmission
• 38mm Keihin carburettor with good throttle response
• Semi-double cradle aluminium frame

Availability
YZ125 and YZ250 from September onwards
YZ85 from December onwards

Yamaha YZ450F and YZ250F
During their debut season the YZ450F and YZ250F have made their mark and shown their potential on both sides of the Atlantic. In the hands of rising star Jeremy Van Horebeek, the YZ450F has raced to 8 consecutive podiums in the MXGP class to give Yamaha 3rd overall in the current World Championship standings.

Over in the USA the YZ250F has had a dominant start in the AMA Nationals, while in Europe the bike has been on the podium in the MX2 World Championship, and currently leads the Women’s Motocross World Championship including two GP race victories.

For 2015 these innovative 4-strokes have undergone a number of important changes that are designed to enhance performance and rideability, while a number of stylistic changes give an even sharper image.

Changes have been made to the fuel injection and ignition settings in order to further improve power characteristics, and these revised settings are designed to smooth out the power delivery on the YZ450F, and to give stronger mid-range power on the YZ250F.

For easier maintenance the air cleaner cover is equipped with quickrelease fasteners that replace the bolts on the current bikes. Both models also receive some detail changes to the engine internals.
The 2015 models also benefit from the fitment of new black rims, which – together with the latest graphics – add to the professional ‘factory-bike’ appearance.

YRRD (Yamaha Rinaldi R&D) will once again be offering a professional quality race kit for the 2015 YZ250F that features a wide range of performance boosting parts.

The YZ250F kit includes:

• Lightweight forged high compression piston assembly
• ECU with special YRRD mapping and rev limiter raised by 500 rpm
• Modified cylinder head assembly with optimum gas flow
• Intake camshaft assembly with higher lift and revised profile
• Cylinder gasket
• High pressure radiator cap up to maximum 2.0 bar
• Machined crankcase cover for higher rigidity and factory appearance
• Optional lightweight con rod

Full information at www.yamaha-racingparts.com

YZ450F Technical Upgrades

• Revised FI and ignition settings for smoother delivery
• Revised throttle body components for lighter throttle action
• New quick-release fasteners on the air cleaner cover
• New black wheel rims
• New factory-style graphics
• New lower engine brackets

YZ250F Technical Upgrades

• Revised FI and ignition settings for stronger mid range power
• Revised throttle body components for lighter throttle action
• New quick-release fasteners on the air cleaner cover
• New black wheel rims
• New factory-style graphics
• Modified piston design
• Revised decompression angle on exhaust camshaft for easier starting
• Special YRRD kit parts available

Availability
YZ250F and YZ450F are available from July onwards.