We get the low down from Shop Yamaha’s AJ Roberts on what it takes to mount a competitive charge at the Hattah Desert Race.The Hattah race is Australia’s most popular dirt bike event. The combination of off road and motocross make it the most sought after race in the country with 600 riders filling the start line each year and selling out in record time. In June, the rolling sand paddocks just outside of Mildura in Victoria, are consumed by riders from all over the country wanting a piece of the Hattah magic.
Many of the riders just roll up on the current bikes and give it a shake, with the fun factor high on the agenda, but if you are serious about winning Hattah, then there are a few steps you need to take to get to the top step.
Its unique in the way the course is designed. Yes, you can drive it in a car. You wouldn’t want to- but you can before the 600 bikes tear it to shreds. It’s essentially a 30-minute sand motocross track with some off-road flavour. The tight wooded and technical sections are joined by wide open fence line sprints up to a few kilometres long and what starts out as a smooth blast in the sand can end up a minefield of bike swallowing sand whoops that can see lap times blow out by two minutes at a pro level and double figures for the weekend warrior.
It is a mental test, a physical test, and a real test of preparation for riders and teams. The riders will tell you it’s the most demanding weekend of the year. A four-hour sprint on a degenerating track that leaves you exhausted, sore and with hands full of blisters. For the motorcycle, it’s a torture test. Sand, whoops, constant riding at race pace only stopping for fuel that pushes the motor to the brink.
One man who has experienced the highs and lows that Hattah evokes, is Shop Yamaha Off Road Racing Team Manager, AJ Roberts. Roberts has been a regular at Hattah for many years and worked with his team and riders to acquire a healthy bank of knowledge of what it takes to be competitive at such a unique event so we tapped into his data for a rundown of what he and his team do to prepare for an event like Hattah.
“Hattah isn’t like any other event and as a result, setting up a bike for it takes a few years of experience to understand what’s required and what works best at a race like this. It’s not like an AORC round as the average speed at Hattah is around 80ks per hour. That is a fast racetrack. If you compare that to an MXGP where they shoot for an average speed of around 55-60ks an hour, you understand just how fast the riders go.
“It’s not like Finke which is more of a straight-line shootout. Hattah has slow sections, tight sections, fast sections, and technical sections so a bike set up that you would use at Finke where straight line stability is the number 1 priority simply doesn’t work here.
“Add to that fuel stops, bike durability, rider fitness and a four-hour race strategy and you have a race that isn’t easy to win.”
1. Oversized fuel tank
On a conventional off road or motocross bike, you would only get one lap before having to refuel. That means you have at least seven stops during the race and that adds time the rider needs to find out on the course to make that back. By reducing the number of stops means the less time wasted in the pits and more racing. We fit a 12.5 litre safari tank to our bikes which means we can go two full laps before refuelling.
The Safari tank bolts up easily to the YZ or WR with only one small modification to the sub frame and is available over the counter at dealerships. By running that oversized tank, we have halved our fuel stops.
2. Steering Stabiliser
Riding a dirt bike at speeds close to 170ks an hour across a shifting surface like sand can make for a very busy front end, so the team fit a steering stabiliser to their race bikes to settle the bike more to get it a more predictable feel in the sand and reduce rider fatigue.
A few things need to be considered here. As mentioned, a regular Finke or AORC set up won’t work well here as conditions are so different from those style of events. We tend to work with a more traditional motocross style setting but take in a couple of considerations. The weight of the bike is increased when the over-sized tank, especially when full of fuel, so that must come into calculations with spring rates and valving.
We also need to make the bike as versatile as possible as it must work well at speed but also be able to steer accurately in the tight bush sections. And that also works in line with rider fatigue, it’s a four – hour race so we can’t go too hard, or we simply pound the rider into the ground. So, we generally end up with motocross style valving – maybe a little softer- with firmer springs and then try and keep a conventional bike balance with ride height around the 105-108mm area.
There are several things to think about here. We clearly need speed, but we also need to maintain it for four hours. We need to keep it cool as overheating is your worst enemy. Being sand, we need to be aware of the clutch and more abuse it can take and work with the rider to ensure it doesn’t destroy the bike in the first two laps.
The simplest way to get more top end is increase the size of the counter shaft sprocket. We run a 15 on the front and while that does take away bottom end, it does give us a significant increase in breath of power and over rev. It’s a cheap and simple thing to do that has an effect on the track.
Also, any mods you do to the motor must be durable as bolting up a performance part that can’t handle four hours of abuse with no maintenance isn’t going to cut it. We have flowed heads and altered cams but steer away from increasing compression or increasing rev limits on the ECU as that only adds strain to the motor. In fact, we have decreased rev limits on some riders over the time to protect the motor has they are riders who always ride the bike high in the rpm range.
The overall concept of the bike is for it to be comfortable to ride at speed for a long period of time. Things like grips can destroy hands so make sure the grips are not overly hard. Ergonomics of the bike play a factor. The bars, levers and even the density of the seat foam plays a part, especially late in the race as imagine having to sprint the last hour with a next level case of monkey butt, or blisters. The riders like Stegpegz as they take some of the pressure from their shoulders and arms and move it to bigger muscle groups in the legs.
If you combine an aggressive engine package and a firm suspension package, you might have the lap record for the first lap, but you might also be fatigued out of the race just passed halfway – so the overall package must be racy, yet comfortable.
Then just add some of the details to the bike. Protection in a race like this in important. Skid plates, hand guards, chain guides and runners all offer protection against the course or the elements. Being predominantly sand, a scoop or paddle style tyre is used on the rear. These offer amazing straight-line traction and simply get you up on the sand and moving. Mousse tubes to stop the risk of flats, a good X-Ring chain to handle the abuse, a 2.0kg radiator cap with a high-performance coolant to reduce over-heating and a hundred litres of fuel should all add up to a good way to start your day at Hattah.