Set-up report Motegi Round 13

Setup

ROUND: 13, PACIFIC GRAND PRIX
October 5, 2003
Circuit: Twin Ring Motegi 
Country: Japan
Track length: 4801 m
Opened: 1997 
Fastest Lap Ever: 1' 49.052 (Daijiro Kato, 2002 - MotoGP) 
MotoGP lap record: 1' 49.947 (Alex Barros, 2002) 
Last year MotoGP winner: Alex Barros
GP250 lap record: 1' 52.253 (Shinya Nakano, 2000)
Last year GP250 winner: Toni Elias 
Circuit tel: +81 285 640001 
Circuit web site: http://www.twinring.co.jp

2002 race summary Alex Barros notched up his first win of the year with a dynamic debut four-stroke performance at the 2002 Motegi MotoGP. The Honda rider produced a strong start to feature well in the opening few laps of the Pacific Grand Prix, with Loris Capirossi (Honda), Daijiro Kato (Honda), Valentino Rossi and Max Biaggi (Yamaha) all making up the leading group. Then, on lap four, the Brazilian took the race lead, closely followed by Kato. With the support of the home crowd the jockey-sized Japanese looked set to chase down the leader until his four-stroke expired. Seven laps later a hard charging Biaggi also became a victim of something unexpected, although his gremlin was tyre related. A risky front tyre choice resulted in a premature end to his fourth place charge. The outcome promoted the trailing Tohru Ukawa (Honda).

The two retirements left Rossi and Capirossi to concentrate on chasing down Barros, the recently crowned MotoGP World Champion making his move on lap 18. Although he held onto the lead for two laps it was clear clutch concerns were hindering Rossi’s progress. Barros took advantage of the situation and went on to win the Motegi MotoGP, his four-stroke debut, by 1.641 seconds, with Capirossi third.

Front row starter Carlos Checa (Yamaha) had a less than ideal beginning to the 24-lap race after entering turn one in tenth place. The Spaniard recovered some of the lost ground, but like his team-mate Biaggi, he was also suffering from a front tyre lacking feel; preventing him bridging the gap to the leaders and eventually forcing him to settle for a safe fifth.

Set-up report YZR-M1
Like many things designed and built in Japan, Motegi is unsurpassed in its design and circuit quality – the surface is seamlessly smooth, offering high levels of grip, and the facilities are exceptional. Yet, despite this high attention to technical detail the Motegi layout looks a bit like a series of drag strips linked together by continual radius second gear corners. Even so it is still technical enough that outright power isn’t the be-all and end-all when it comes to winning races here.

In fact in some respects too much aggressive power can be a hindrance at this particular venue. For this reason Yamaha has increased its efforts to further improve the YZR-M1 in regard to tractability and predictability on the power. These performance characteristics are essential since most of the power will be driven through second and third gears, while exiting slow speed turns, only moments after completing some rather heavy braking.

This combination of hard braking to hard acceleration over a very short distance complicates things further for the riders with aggressive weight transfer being a catalyst for instability. Although circuits such as Le Mans share a similar reputation of a stop-and-go layout, Yamaha’s success is yet to present itself in Motegi. For this reason a balanced and usable base geometry will be the focal point for those riding the M1.

The main aim, in both instances (acceleration and braking), is to cater for the weight transfer, to minimise the pitching effect. To do this the basic chassis package won’t be too far removed from what was run during the Le Mans round earlier in the year. The rear of the bike will be slightly lower and the front set slightly higher, when compared to other circuits, to offer the braking stability needed – reducing the likelihood of the rear wheel leaving the tarmac. The front fork springs will boast a slightly higher spring rate, but unlike Le Mans, the advantage is that the damping won’t have to cater for any real bumps while the front forks are compressed.

The rear shock on the other hand will run a slightly softer spring with a high amount of preload. This will help to offer the feel and consistency under power while preventing the bike from squatting to the point which can cause it to run wide or, in extreme circumstances, wheelie. At the same time suspension technicians will also have to consider the effects of the rear shock pumping through its stroke – a common concern on a track where the bike is driving hard off a slow speed hairpin.