02-05 Honda CRF450R Close Ratio 5 Speed Gearbox

This gearset is a direct replacement to the Honda CRF 450 5 speed motocross gearbox with the added advantage of undercut engagement dogs and road racing ratios.

The Nova close ratio gearbox gives a performance gain of up to 1.5 seconds a lap depending on the length of the circuit.  The gear ratios are optimized for road racing to keep the engine working between its peak torque and peak power.  The ratios of the standard box are designed to give tractability off-road, and as such cause the engine revs to drop below peak torque meaning drive from the engine is not optimized.  Over the length of a 3.9km circuit, lap time improved by 1.5 seconds.

This kit includes only the loose gears.

Superfinished in house as standard.

NOTE: The gearbox should be assembled using the standard shafts, bearings, bushes, thrust washers etc.

Honda Moto X Box in Parenthesis

1st 15 – 26 1.733:1
} 22.0% (18.3%)
} 16.5% (16.0%)
} 11.5% (15.0%)
} 8.3% (13.4%)
2nd 17 – 23 1.353:1
3rd 23 – 26 1.130:1
4th 23 – 23 1.000:1
5th 24 – 22 0.917:1
Overall reduction 1st – 5th 47.1% (49.5%)

AN ALTERNATE 1ST GEAR RATIO IS AVAILABLE AT 15 – 28 (1.867:1) TO GIVE A 1ST-2ND PERCENTAGE DROP OF 27.5% AND AN OVERALL OF 50.9%

CRF Primary Drive
CRF Billet Engine Case for RS125

02-05 Honda CRF450R Close Ratio 5 Speed Gearbox

Price £1270.00

+VAT (if applicable) & Carriage.

Nova assembly: 78