At 7700 miles my chain started to make a clicking noise. Turns out it was loose at several links. I commute 100 miles per day and clean/lube the chain once per week. I thought the chain would last at least 10k miles.
After doing some research, a friend referred me to sprocket center. DID 520 VX2 gold x-ring chain and both JT sprockets were $131 shipped. If I went with the black chain, it would have been $10 cheaper. Place was cheaper than anyone else I found on the net.
90% of my ride on the ninja is commuting (also have a R6 for weekends), 100 miles per day between 75mph and 85mph. I wanted a little lower cruising rpm, so I chose the 15 front and 40 rear gearing. Stock gearing is a 3.00 ratio and this setup equals a 2.67 ratio.
With the new gearing, cruising in 6th gear the motor is spinning about 900 rpms lower. The speedometer is off by about 10 mph but now the tach is pretty much the speedo. 7000 rpm is right at 72 mph. The bike feels a lot smoother and quiter too. Power wise, when I want to pass a car, just twisting the throttle it doesn't pick up as fast anymore but still ok. If I really need to pass fast, just downshift a gear. Acceleration from gear 1-4 is still just as fast, just doesn't feel as fast as with stock gearing. There's a straight stretch of road near my house, always gun it from 5mph to 80mph. I still get to 80 at the same spot but instead of being in 4th gear, I'm still in 3rd. Top speed is still the same. Both setups I still max out at 105-106 mph, the difference is now I reach it in 5th gear, changing to 6th gear still leaves it at 105, just lower rpms.
What I gained from this change is exactly what I wanted. Lower cruising rpms with a smoother ride while still getting the same acceleration. Also with the longer 1st gear, putting along in traffic when you close the throttle, there is less engine braking now. It's a much smoother on/off throttle response. No more jerky on/off throttle. Lastly the best part of it is the MPG. With the stock setup I was getting around 58mpg. With this new higher gearing, I am now getting right at 62 mpg. Pretty good gains.
Which now leads me to wonder, why haven't any of the motorcycle manufacturers added a 7th gear purely for cruising? All the cars are getting more gears in order to lower cruising speed rpms and increase mpg while maintaining good low speed acceleration. If the 300 came with a 7th speed that say, drops rpm by 2000, that would be perfect. You still have just as much fun shifting all the lower gears while cruising on the highway at low fuel saving rpms.