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I have spent a lot of time testing on the 2023 MX machines you see below. I have went back and forth on several bikes to see which gearing would be good for the average rider. I did the evaluations on tight clay based tracks to flowing sandier based type desert 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 2023 MX test machines so far. A couple of these gearing specs have evolved since 2022 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. However, if a certain bike does need an engine character change or maybe the transmission spacing needs help, we will try different gearing. These gearing specs are for stock engines or with 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 preferred, to compliment the recommended gearing specs. As usual if you have any questions I am here to help you. Email kris@keeferinctesting.com and I will be happy to assist you.
Yamaha:
YZ250F: Stock 13/50 Recommended: 13/50 Recommended ECU Setting: (Keefer Free Feeling Map)
YZ450F: Stock 13/49 Recommended: East coast/deep dirt conditions we have been running 13/50 gearing as it helps 2nd gear recovery and shifting into third gear sooner than the stock 13/49. West coast, 13/50 can provide better third gear rolling speed through corners. 14/52 is also an option if you want a smoother roll on with a better shock acceleration feel/comfort as it doesn’t bind the chain as much as the stock gearing (when rear end is loaded).
Kawasaki:
KX250: Stock 13/50 Recommended: 13/51 Going to a 13/51 helps with third gear roll on power out of corners. The added tooth doesn’t negatively affect the second gear stretch as much as originally thought so sticking to this 13/51 gearing has been a mainstay at most tracks.
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 get into third gear quicker on flowy/rough tracks where getting into third gear is needed for chassis comfort.
Suzuki:
2023 RM-Z250: Stock/Recommended 13/50 White coupler (Stock)
2023 RM-Z450: Stock 13/50 Recommended 13/51 White coupler (Helps pulling power down low on deep tracks).
Honda:
CRF250R: Stock 13/50 Recommended: 13/51 (Helps rider get into third gear earlier and gives more pulling power without sacrificing too much second gear roll on). The stock 13/50 is decent for flower tracks since the transmission spacing is much better in 2022, but the 13/51 will allow you to just run third gear in corners similar to the YZ250F.)
CRF450R: Stock 13/49 Recommended: 13/49-50 I would rather go to a 14/52 on the CRF450R but the slave cylinder is too close with a 14T installed. Going up a tooth can help you with lugabiity because the Honda isn’t that great as the other 450s when riding a gear high.
KTM:
250 SX-F: Stock 14/51 Recommended 14/52 This will help third gear roll on response through corner exits in soft dirt conditions without sacrificing much 2nd gear pulling power. If riding hard pack dirt, leave gearing stock.
350 SX-F: Stock 14/52 Recommended 14/52
450 SX-F: Stock 14/51 Recommended 14/50 I have tried going to a 13/52 but it didn’t help my third gear roll response on as much as I would like so I settled on a 14/50 in order to be able to use send gear more/longer.
Husqvarna:
FC 250: Stock 14/51 Recommended 14/52 This will help third gear roll on response in soft dirt conditions without sacrificing much 2nd gear pulling power. If riding hard pack dirt, leave stock.
FC350: Stock 14/52 Recommended 14/52
FC450: Stock 13/51 Recommended 13/50 I have tried going to a 13/52 but it didn’t help my third gear roll on (response) through corner exits as much as I would like so I settled on a 13/50 in order to be able to use send gear more/longer.
Gas Gas:
This set up on both bikes will help settle the rear end out of corners and help with 2nd-3rd gear transition exiting corners.
MC 250: Stock 14/51 Recommended 14/52
MC 350: Stock 14/51 Recommended 14/52
MC 450: Stock 13/49 Recommended 14/52
