All eyes at the Twin Ring Motegi circuit this weekend will probably be on reigning world MotoGP champion Jorge Lorenzo, who is leaving Yamaha to join Ducati next season and is finding it difficult to get permission to test for his future employers. Or fans could focus on this year's championship leader Marc Marquez, who has a chance - mathematically - to wrap up his third title on Sunday. That would please his Honda bosses no end as Motegi is their home track.Standing firmly between the Repsol and that dream is the legendary Valentino Rossi, Lorenzo's soon-to-be-former teammate and Marquez's bitter rival.It got nasty late last season when the Doctor kicked the young Spaniard to the kerb at Sepang, and Marquez has spent much of 2016 kicking sand in the face of the playground bully.It's a contest for the ages, the ageing superstar vs the young pretender, with no love lost between the riders or the marques.Ducati have made great strides this season and, with Lorenzo on board, are sure to be a major factor next year. But it is blue vs orange going down to the wire with four races left in the 2016 calendar.Marquez holds a 52-point lead over Rossi (and 66 over Lorenzo), so he could be crowned champion with a victory and double calamity for the Yamaha squad. Unlikely, but possible.Lorenzo, Marquez and Rossi have dominated the class since the younger Spaniard joined the big boys in 2012, but it could well be the fourth wheel of this sidecar race who ends up on the top step of the podium on Sunday morning.Marquez's teammate, Dani Pedrosa, is the master of Motegi, the sweeping corners and the absence of a truly long straight eliminating the advantage his heavier rivals usually have.A win for Pedrosa would satisfy Honda honour, as well as ensure that this absorbing title race goes down to the wire.Motegi will be the first opportunity for South Africa's KTM boy racer, Brad Binder, to enjoy as Moto3 world champion.He clinched the title at the last outing in Aragon and vowed afterwards to complete the season in style. He won't be taking the final four rounds of the series as victory laps, even though he will be moving up to Moto2 next year.The class is the tightest of the three on the circuit, with Johann Zarco just one point ahead of Alex Rins, but they are 40 points clear of Sam Lowes in third place...