This weekend's Grand Prix of Bulgaria marks the mid point of the 2007 Motocross world championship season, in which Josh Coppins has been kept on his toes in MX1, while Antonio Cairoli has dominated MX2 class.

Coppins has built a huge 90 point lead over Suzuki's Steve Ramon by being up front at each and every event, winning eight of the 14 motos. However, the recent French GP saw a breakthrough ride from Ramon, who took a strong race two victory - only his second ever moto win in the premier-class - and will now be seeking his first overall triumph.

But while Ramon's season is in the ascendancy, team-mate Kevin Strijbos was forced to miss race two in France due to a knee injury - and has already been ruled out of this weekend's Bulgarian battle.

Strijbos, along with KTM's David Philippaerts and Kawasaki's Billy Mackenzie, have already proven they can win this season, while Tanel Leok needs to convert his unquestionable one lap speed into a race distance.

Joining Strijbos on the sidelines will be Max Nagl, who broke his collarbone in France, but fellow factory KTM rider Jonathan Barragan hopes the shoulder he injured in Japan will be back to strength.

After winning the MX2 Grand Prix of Japan, GPKR's reigning champion Christophe Pourcel was relegated back to second position in his home grand prix, but will attempt to halt Cairoli again this weekend. The Italian won the opening moto in Bulgaria last season, but fell in moto two for sixth overall.

KTM Red Bull's Tyla Rattray looks the most likely rider to join Cairoli and Pourcel on the 2007 victory list, while Pascal Leuret, Nicolas Aubin and Tommy Searle could spring a surprise.

Practice and qualifying for the Grand Prix of Bulgaria will be held on Saturday, with all four races on Sunday.