YZ400/450F Top Gear Ratios?

3 replies to this topic
  • flowrider

Posted April 09, 2007 - 09:32 PM


Does anyone know what the ratio of top gear is for both the 400 and the 450?

The reason I need to know is I have an 89 TZ250 chassis and both engines available to me. The 450 engine is on a shelf in my garage and the 400 engine is in my dirt bike. I got the 450 engine for the TZ chassis before I realized it only has a 4 spd tranny, which has me wondering if I should put the 450 engine in my dirt bike and use the 400 engine in the TZ. Any help would be greatly appreciated.

  • grayracer513

Posted April 09, 2007 - 10:06 PM


What year 450?

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  • flowrider

Posted April 11, 2007 - 05:22 PM


2003 450F vs 99 400F

  • grayracer513

Posted April 11, 2007 - 05:45 PM


The '03 has a Primary Ratio of 2.818, and a top gear of 1.050, for an overall top of 2.96 at the output shaft.

The '99 has a Primary Ratio of 2.952, and a top gear of 0.952, for an overall top of 2.81 at the output shaft, making it about 5% higher geared. Taking two teeth off of the rear or an equivalent, would even things up.

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