I was thinking of getting some new tires for my 400ex and was wondering if I switched to 23" front xct's and a 22" rear. What would I need to do woth the sprockets to keep it close to stock.
Also, I hear guys saying they switched to a 14 tooth front sprocket, What is stock size, and what does this do (speed or grunt).

 

With the taller tires, going to a 14 tooth front sprocket will be about the same gearing. With stock tires, the 14 tooth change would be more umph and less top speed.

 

I have XCT'S in my 400EX and i'm running 13/39, perfect for trail riding. This gearing combination is not heavy on the motor.

 

Woodrider, good question, I just ordered XCT's (23in fronts and 22in rears) from rockymountainatv.com. I guess I could count the teeth, but I'm at work, goofing off, what's stock 15? First gear seems kinda tall to me. Plenty of power for low end, but it will run up pretty good.

 

I have the XCTs on my 400, and I have changed to the 14 tooth front sprocket. With the stock gearing and the taller tires, I was having to slip the clutch a lot if I had to creep over something.