Hey guys, have a non Harley bike related question on a project I am working on a Kawasaki KZ 650, it runs stock with a 16T sprocket up front and a 42T in the back, I plan on running a 14 up front and keeping the rear the same, can anyone tell me the change is RPM to speed this will be? Anyone have a good web site to run different ratios? Thanks for the help.

 

Here's a good website to mess around with gearing. It will show you speed vs. rpm and let you compare different sprockets. http://www.gearingcommander.com/

For a quick reference, just know that you are increasing your ratio (meaning it will be slower at a higher RPM than stock). Multiply your speed at a given RPM by (14/16) to get your new speed at that RPM.

You can reverse the factor (16/14) to determine your new RPM at a given speed.

Example: at 50mph and 5000 rpm, you would now run 50*(14/16)=43.75mph at the same 5000rpm. You can reverse it get 5000*(16/14)=5714RPM at 50mph.