Specifications
The following shows the key specifications issues for each class. It was also introduced for the 2005 year, that under rule 2.10.5: 'No fuel on the motorcycle may be more than 15 K below ambient temperature. The use of any device on the motorcycle to artificially decrease the temperature of the fuel below ambient temperature is forbidden. No motorcycle may include such a device.' This stops an artificial "boost" gained from increasing fuel density by cooling it.
Read more about this topic: Grand Prix Motorcycle Racing