Twenty-seventh in a series of helpful pointers written by MotoAmerica’s technical manager
If you ride a late-model sportbike on a racetrack with stock final-drive sprockets, you will generally find that you are in first gear quite a bit and rarely need to grab fifth or sixth. That’s fine for a track day, but if you want to get a little more out of the bike and use more of the available ratios, it’s a good idea to replace the chain and sprockets.
Here are a few simple rules: Use a high-quality 520 O-ring chain for 600 to 1000cc motorcycles (expect to spend $150 to $250 on the chain alone). The reduced-size chain will save rotational mass and improve acceleration. If you expect to change sprockets throughout the year for different track setups, use an aluminum rear sprocket. This will allow the sprocket to “wear” to the chain each time you change the sprocket rather than the chain wearing to the sprocket. If you don’t plan to change gearing, use a steel rear sprocket and replace everything as a set when necessary. By doing this, you will get maximum life out of the final-drive system.
As for which ratio to use, it’s common for motorcycle shops to sell one-down, two-up kits (one tooth down on the countershaft sprocket and two up on the driven sprocket) but that isn’t always the best choice. Really, the best thing to do is ask around. Go to your local track and find out what racers are running. Most riders love to talk about gearing and why you have to be really fast to use what they are using. Plus, it’s a good excuse to watch a motorcycle race.
If you would like me to answer a tech-related question about the MotoAmerica Series or if you just have general motorcycle question, please email me at email@example.com.