Yeah, the 400 and 450 are different up front. I could have just gone out to the garage and looked, duh! I am betting going down I tooth in front is going to be to radical. You could try 1 or 2 teeth bigger in back. Those are standard Honda and are readily available. Usually you have enough chain to go one tooth bigger in back. But 2 theeth, will probably require a longer chain.

 

Thanks to all who posted. The CRF450 stock front sprocket has 13 teeth and the splines match up perfect. Just putting around the yard, I was able to tell a huge difference in the low end and throttle response. I think the change will be just right for the trails. I like going fast but occasionally I will need to slow down and wait on my friends and possibly turn around or slowly climb a hill. [img]i/expressions/face-icon-small-happy.gif[/img]

I saw on another forum that someone used a 400ex front sprocket for their 450R and I am calling BS on that. I compared the two at a dealer today and they don't even look the same and the mounting hardware is totally different. The only thing that appears to be the same between the two are the splines. The back sprockets for a 400ex might work, but I can't really comment on that as I haven't really investigated it and don't want to steer someone in the wrong direction.

Anyways, thanks for all the help- I'll know more after my ride this weekend, but I know this is going to make a huge difference on the trails and hill climbs. [img]i/expressions/face-icon-small-smile.gif[/img]