I was going to bump up the front sprocket on my 2000 400EX a tooth, until I was told I would have to remove the case saver when running a 16-tooth sprocket. Any truth to this?

 

Yes. Only if you want to risk not having a crankcase would I do this.I went down to a 14 and didn't like it.(I had the dealer do it) I put my 15 back on and it had little clearance. EVERY TOOTH ADDED INCREASES DIAM. ABOUT 7/16" OR 1/4" ALL AROUND.If you're going for speed, increase youre rear sprocket and open up your wallet too.

 

You decrease the rear sprocket for more speed. I agree keep the case saver.