In 2010 the Yamaha engineers re-invented their 450cc four stroke motocross engine.
They started off by turning the cylinder around so the inlet was at the front of the bike and the exhaust came out the rear of the cylinder head.
Next they changed the entire engine placement and lifted the front of the motor so the motor sits in a downward slope to the centre pivot point of the bike, improving mass centralisation.

Squeezing in a new EFI system was next and the Fuel Injection system was moved to the front of the bike along with the airbox. The tornado style exhaust finished off the motor department as it weaves its way from the rear of the cylinder, through the centre of the bike and out into the atmosphere.

So when Yamaha released the details of their 2011 YZ450 and there were no major changes, we weren’t exactly surprised.
The push rod that activates the clutch has seen some slight modifications, but apart from that the blue empire stayed with what they know for season 2011.

Suspension & Chassis

KYB have been taking care of the suspenders under the big bore YZ thumper since it was first introduced as the YZ400F back in 1998.
Suspension has come a very long way since those days; the 2011 YZ450 comes with Twin Chamber KYB speed sensitive forks and a KYB shock which is very specifically designed for the YZ450. A 22mm triple clamp offset comes standard and is designed to maximise the cornering performance without compromising too much stability in the front end. 

The top triple clamp also features extra an extra mounting position for the handlebar clamp, a handy inclusion for those of us who would like to move their ’bars that bit further forward and open up the cockpit. The lightweight aluminium frame is crafted from 16 individual components welded together to come up with the most balanced YZ450 to date.

The bilateral beam frame design promotes nimble handling with a focus on cornering and an aggressive rider feel.
The sub-frame is designed to suit the rest of the Yamaha’s characteristics and is once again constructed from the highest quality aluminium.
The rest Yamaha’s are renowned for an exceptional build quality, from front to back, and bottom to top the YZ450 is a quality product.

Excel rims and Dunlop tyres do the hard yards in the dirt, the D756 rear tyre is great and has been seen on many race bikes over the years, the D742 front tyre is a good across the board tyre but doesn’t stand out from the crowd in any one type or terrain. Pro Taper handlebars have been supplied standard on the Yamaha four-strokes for a few years now and seem to be doing the job just fine. The front and rear disc brakes do a good job of pulling up the big YZ, no problems there.

It would be nice too see some of the Japanese manufacturers look at an oversize 270mm front disc as a standard production item, most of their European competition are running larger front discs and the changes are especially loved by the big bore riders on the larger, heavier bikes. Air filter maintenance requires a bit more time on the new Yamaha. Once you take off the seat, undo the tank and flip it up out of the way using the hinge system on the rear of the tank and the wire tank holder which comes in the YZ450 spares kit.

Then it is time to take off the air filter cover and now you have access. Once you have the air boot open it is easy to clean and service the airbox and put that clean new filter into. The two tone colour scheme looks cool, with either the Blue and White, or the White and Red to choose from. It’s a nice touch from Yamaha which allows the customer that little bit more option when buying their spankin' new bike.

The dirt

Riding the YZ450 is different to riding any other Japanese 450 on today’s market. Its not a massive leap away from the traditional feeling of a 450cc four stroke, but it's noticeably different to the general competition. 

From the moment you open the throttle things are a little bit different, with the powerful sound of air being sucked in through the inlet at the front of the bike right beneath your legs. The power begins to come on strong off the bottom and continues on pulling hard through the mid range. The bottom to mid range gets the power to the ground very quickly and the YZ pulls very well out of the tight turns.

Once you keep pushing the revs past the mid-range, the power curve begins to mellow out and continue onto the rev limiter. The top end is not where all the power is on the big bore YZ, but for the majority of riders out there, including us here at Cycle Torque, the abundance of bottom end power makes riding the fun and enjoyable to ride and doesn’t leave us having to looking for power.
The standard gearing on the YZ works well, it’s a 13-49 combination and after testing the Yamaha at a number of different tracks we never came away from a ride looking to change the sprockets. The standard KYB suspension settings work well across the track in most situations.

Taking on the rough stuff was a dream, the suspension has a plush and forgiving action on the track and makes the rider feel comfortable all around the track. We made some clicker adjustments and we gained the most improvement from stiffening up the compression setting on the forks and setting the rider sag on the shock at 105mm.

The Final Say

Its hard to say a bad word about the YZ450, Yamaha has created one of the most innovative and creative bikes on today's motocross market. The YZ450 turns heads wherever you go and has the crowds talking about what the funky design is all about.

It works well on the track and even took Aussie boy Jay Marmont to his third successive Australian MX Nations championship in 2010.