Breaking cover at Round 8 of the Japanese Motocross Championship in Sago on October 23, MX1 Honda World Motocross riders Rui Goncalves and Evgeny Bobryshev were riding aboard what looks like a 2013 prototype Honda CRF450R.

While official details are scarce, the prototype model looks to have a modified exhaust header, which now exits from the right side of the cylinder instead of the left. It wraps around the left side of the frame with the mid-pipe crossing back over the rear of the cylinder to join the muffler in its standard position - on the right side.

Also pricking our interest is what looks to be a factory-mounted hydraulic clutch - something we've already seen this year on both Chad Reed's and the GEICO Honda team rider's CRF450Rs. The bike also comes with an aluminium fuel tank.

Goncalves took first and Bobryshev finished up third in the 450 class (IA1) at the Japanese round.

Expect the Honda World Motocross team to refine a 2013 model during the 2012 World Motocross Championship.

Take a look at more shots of the 2013 prototype model from the Japanese round.