Below are the base ratios for both motor programs. The gear selections are based on an average track and may not fit all situations. You can help. If you have a base setup for either motor on a track not listed, share it. ANY track that you have turned laps on is welcome. Just send an email to webmaster@xcelchassis.net
TIP: XCEL MODIFIED CHAIN TENSION ADVICE Since you are changing gears, you may want to see how to tension that chain. Link is a 2-minute video on that topic.
If you have a different size front gear, the ratio chart will help you convert to the correct rear gear recommendation to your front gear size.
Look up the gear that is listed on the first chart. Use it to find the closest match to your front gear and what the rear gear would be.
Let’s use Lindas Speedway for an example:
Lindas Speedway on the chart shows a 13-46 configuration in 3rd gear, which if you look up on the ratio chart is: 11.91 (3rd gear)
If you have a 12-tooth sprocket on the front, you will look for the 12-XX gear by comparing the chart for the closest thing to an 11.91 ratio.
For the 12’s sprocket chart, 11.84 is the closest and it appears twice.
First is an 12-42 in third gear and a 12-48 in forth gear. What you choose is based on what you have.
In addition to using this for changing the front gear, you could also use it to tweak your gearing for a specific track.
FYI: The Yamaha motor has been demonstration more pull (vs. more rpm on the Suzuki) and it is recommended that you use larger gear combinations, if possible, to handle the strain.