Your engine any engine has a span of RPMs it runs it best. But there are times the more RPMs out side your best curve are useful. Once the bike is moving at speed some of those RMPs outside the range will still allow more top end speed.
Example My big sidecar rig. Factory engine no exhaust or intake changes . it has a power vision with a stock improved tune. Factory redline is 5,400 rpms. With the tune it is now 6,200. The M8 engine has plenty of power to move the rig. It will do so fairly fast . There are times when you may wish for a bit more range in a gear. Coming on a ramp in the mountains up the grade. Those extra RPMs allow you to run the gear out a bit more and pick up more speed. That happens because the gearing is low enough you still have the torque to pull it even if it is not in the best range.
Your Street will act the same way. The Street 750 was a pretty wide operating range in the higher gears . 6th for 45 mph up is no problem. It is a light bike and with a light rider the extra RPMs may produce more top end speed in any gear.
But running high RPMs with no load on the engine like in 1 and 2nd gear will be hard on it over time. As I said just because you does not mean you should. Most people will not control the use of the extra RPMs over time and will be running a lot of unneeded RPM's. That will cause early wear. Long as you are ok with it and know it going in , have a blast.
My Street 750 with No changes to the engine or drive line tugs the sidecar very well, even with passenger in it. Solo750 will tell you the same thing. He is a good size man and with the sidecar his move
Last edited by smitty901; 09-12-2019 at 02:51 PM.