k, managed to get into the work email system. Details are;
BIKEBIZ (www.bikebiz.com.au)
RK Chain and JT Sprocket Combos PRICES:: 520 XSO RX-Ring Kit (A$218.95)
Please enter bike Make (eg Yamaha):: Make...Honda
Please enter bike Model (eg 'YZF R1'):: Model...MC21
Please enter bike Year (eg '2003'):: Year...
Please enter Front Sprocket size:: # Teeth...15
Please enter Rear Sprocket size:: # Teeth...40
A$218.95

FWIW i have a chaingang front and rear sprocket on the MC16...nothing special and heavy

Andy......I thought a 40 tooth rear was standard not a 42?