CRF250R/X similarities

[W00TsP0P]

How similar are these engines? And what parts are or are not interchangeable?
I am always thinking of how I can improve my F250R for the trails (besides buying a 30# heavier F250X). Would the X trans be a no mod direct drop in for the R model? Does anyone have the ratio specs on both of these transmisions? Honda specs. just say wide or close ratio trans depending on the model.

 

[MikeS]

I will upload a spreadsheet I did later on today.

3rd gear on both bikes become almost identical with stock gearing, the X is spread out before and after 3rd. Primary ratios differ. You can change the gears between them but it is a pain. adding 4,5th from the X to an R may help. I would like to add 1st and 2nd from the R to my X if the 1st gear main shaft will fit.

 

[W00TsP0P]

Thanks let me know where I can look for that spread sheet

 

[W00TsP0P]

I got a hold of an X model parts manual and was able to view the microfiche for the R to make comparisons. It was interesting to see that the part numbers for the two models were very similar but different. I was able to calculate the ratios from the parts manuals.