I have spent a lot of time testing gearing on each 2020 machine you see below. Going back and forth on several different types of tracks to try and get you a great baseline setting for your new bike. I did my evaluations on tight clay based tracks to flowing sandier based type courses. Since the word “gearing” is still in the subject line in a lot of my emails, I thought I would condense some of the best gearing specs I have come up with for the 2020 MX test machines that I have. A couple of these gearing specs have evolved since 2019 so don’t expect some of these to be the same from last year. I DO NOT however just change the gearing for the sake of changing the gearing like some other media testing outlets, but if a certain bike does need something different, I will most certainly recommend that gearing. These gearing specs are for stock engines or with stock/aftermarket mufflers. If you have engine work done to your bike, chances are you could change gearing on a few of these machines. I also attached a couple links to some ECU maps (to a few bikes) that I liked to compliment the recommended gearing specs. As usual if you have any questions I am here to help you. Email firstname.lastname@example.org and I will be happy to assist you.
YZ250F: Stock/Recommended 13/50 ECU: (Keefer Free Feeling Map)
YZ450F: Stock/Recommended 13/49 or 14/53 ECU: (TP 3.0) The 14/53 gearing will help the chassis settle more on acceleration as well as help calm the bike on de-cel. This also keeps third gear very usable in almost all track conditions.
KX450: Stock 13/50 Recommended 13/51 ECU: (Keefer Map) You can view the KX450 map here: https://www.keeferinctesting.com/motocross-testing/2019/8/25/2020-kawasaki-kx450-reviewbaseline-settings
Going to a 13/51, instead of the stock 13/50 gearing, helps the rider use third gear more through corners. The stock 13/50 will not pull third gear in corners without using a lot of clutch. We ran 13/49 last year to use second gear more, but have transferred over to using third gear, rolling through corners, which makes for less fatigue and a happier KX450 chassis.
KX250: Stock/Recommended 13/50 ECU: (Keefer Map) You can view the KX 250 map here: https://www.keeferinctesting.com/motocross-testing/2020/1/6/2020-kawasaki-kx250-top-5-mods
RM-Z250: Stock/Recommended 13/50 White coupler (Stock)
RM-Z450: Stock 13/50 Recommended 13/51 White coupler (Helps pulling power down low on deep tracks)
CRF250R: Stock 13/48 Recommended 13/49 (Helps rider get into third gear earlier and gives more pulling power without sacrificing second gear roll on). The stock 13/48 makes second and third gear feel super short/close together, but the 13/49 will allow you to just run third gear in corners.)
CRF450R: Stock 13/49 Recommended 14/52 (Helps free up rear end feel on square edge/braking bumps. Will relieve some rigidity near the swingarm.)
This set up on all three bikes will help settle the rear end out of corners/square edge/braking bumps and help 2nd-3rd gear transition.
250 SX-F: Stock 14/51 Recommended 14/53
350 SX-F: Stock 14/51 Recommended 14/53
450 SX-F: Stock 13/49 Recommended 14/52
This set up on all three bikes will help settle the rear end out of corners and help with 2nd-3rd gear transition exiting corners.
FC 250: Stock 14/51 Recommended 14/52
FC350: Stock 14/51 Recommended 14/52
FC450: Stock 13/49 Recommended 14/52