The specific size of the space between the two forks of a Suzuki Gixxer can vary depending on the model and year of production. However, for the latest generation Gixxer SF 250, the space between the two forks is typically around 200-205mm (approximately 7.87-8.07 inches). It's important to note that this measurement may differ slightly for different model years or variations of the Gixxer, so it's always recommended to consult the official specifications or contact a Suzuki dealership for the most accurate information regarding a specific model.