- Round 12: Twin Ring Motegi, Japan
- Track length: 4801 m
- Opened: 1997
- Fastest Lap Ever: 1' 46.673 (Makato Tamada, 2004)
- MotoGP lap record: 1' 48.524 (Makato Tamada, 2004)
- Last year MotoGP winner: Makato Tamada,
- Circuit tel: +81 285 640001,
- Circuit web site: http://www.twinring.co.jp
2004 race summary;
Last year Valentino Rossi secured a second place result at the Japanese Grand Prix at Motegi after a closely contested battle with that weekends' fastest rider Makoto Tamada (Honda). Rossi led the early stages of the 24-lap race but lost his advantage to the Japanese rider from lap ten onwards. In front of a strong crowd, Rossi made an excellent start from his front row grid position, leading into the first corner and thus escaping a six-rider pile-up that claimed Colin Edwards (Motegi was his only race of the 2004 MotoGP season in which he failed to score points). Rossi and Tamada charged away from the remains of the pack, with the former leading until Tamada made a successful pass along the back straight on lap ten. From that point on Tamada built a gap over Rossi, and ended the race just over six seconds ahead of the Italian.
Set-up report YZR-M1;
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 is far from being a technically challenging circuit. The track can be characterized as a series of 'drag strips', linked together by continual radius second gear corners, a layout that isn't liked by many and disliked by more. Even so it is still technically challenging enough that outright power isn't the be-all and end-all when it comes to winning races.
In fact in some respects too much aggressive power can be a hindrance at this particular venue. As a result this should prove to be of benefit to the 2005 YZR-M1, which beside shear horsepower also has a very predictable powerband with an excellent 'throttle linearity'. This performance trait is essential since most of the +230 horsepower will be driven through to the rear wheel on the exit of second and third gear corners, only moments after completing some rather heavy braking.
This combination of hard braking to hard acceleration complicates things further with the aggressive weight transfer being a catalyst for instability. For this reason a balanced and usable base geometry will be the focus point for those riding the M1.
The main aim in both instances (acceleration and braking) is to cater for the aggressive weight transfer by minimizing the pitching effect. To do this the basic chassis package won't be too far removed from what was run during the Le Mans test 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 damping won't have to cater for any real bumps during the period 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.