[redyaris]

The basic problem is that in stock configuration in 6th gear at 100 km/h [60 mph] the throatle is between 50% and 80% open, and running on the carb main fuel circuit, after streamlining the bike the throatle is only 10% open and running on the slow speed and the main fuel circuits. in stock configuration this part of the fuel schedule is only used for a few second at a time as the bike is accelerting. the slow speed fuel circuit in the carb is there to deal with fuel management from idle to up to the point when the flow of air through the carb is enough to keep the main fuel circuit happy. The streamlining doesn't change this condition. The streamlining changes the throatle position required to maintain 100 km/h thus putting the carb into a part of the fuel schedule that is very poor in that the fuel/air ratio is maybe 9 or 10:1 rather than 14:1. the best solutions if you have the money are fuel injection or smaller carb or a single carb. reducing the jet size will work up to a point, after which the carb will provide a overly lean mixture that will cause engine damage and poor performance... but changing jet size is easy and cheep and it may be enough. [?]
So long as the leaning out occures at a speed high enough it won't matter I only need the speed range up to 150 km/h, not 210 km/h.