Converting an CRF450R to an X

MMH

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#1
How small of a front sprocket on a CRF450R

Want to improve low speed/off-road driveability of my CRF450R (yea I know that an X would have been a better choice, but this is what I got). What is the smallest number of teeth on the front sprocket that I can go with? How many teeth front & rear on the stock sprockets?
 

MMH

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#2
Trans Ratios CRF450R vs. X

The following are the ratios I got from my manual for the CRF450R:
Primary Reduction - 2.739
1st gear - 1.800
2nd gear - 1.470
3rd gear - 1.235
4th gear - 1.050
5th gear - 0.909
Final Reduction - 3.846

How do the ratios on the X compare?
 

MMH

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#3
CRF450R Engine Power, Torque & RPM range

What is Engine Power, Torque & RPM Range (i.e. redline) for the CRF450R? All I know is that the idle speed is 1700 RPM. What is the top speed (MPH) of the bike?
 

MMH

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#4
I know that it is not practical to make a 100% conversion, but I am trying to put together a list on getting a CRF450R more off-road worthy. Here is a list I came up with:
- 100W stator & lights - would not want a battery or worry
about electric start - alternator to directly power lights
- Heavier Flywheel (13 oz. ?) or possibly rekluse clutch. Heard
alot about the rekluse, but concerned about excessive
slippage (even if it is automatic) & subsequent cluch wear
- Lower gears (smaller front sprocket) - will live with lower top
speed
- Expansion tank from 250X - would leave radiators alone (even
if they are a little small for off-roading)
- Kickstand from X

Can anyone help with suggestions or part numbers?
 

lwsmithjr

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#5
In '03, stock ratio was 13/50. In later years they changed to 13/48. Personally, I would not go smaller than 13 on the front. The smaller bend radius of a smaller front, along with the torque of the 450 would cause additional stress loads.
 
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MMH

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#6
lwsmithjr said:
In '03, stock ratio was 13/50. In later years they changed to 13/48. Personally, I would go smaller than 13 on the front. The smaller bend radius of a smaller front, along with the torque of the 450 would cause additional stress loads.
Looks like you meant to say that you would not do, not that you would do. Right?
 

XRpredator

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#7
you could probably get away with a 12, but I wouldn't go any less.