Front sprocket chain 520 Afam for Yamaha YZ 400 F 98-99

THE PHOTO IS GENERIC AND NOT REPRESENTATIVE OF THE PRODUCT FOR THE DIMENSIONS REFER TO THE TECHNICAL DRAWING

Available in the "normal" version or in the "self-cleaning" version, where available it can be selected in the drop-down menu for selecting the number of teeth
The "self-cleaning" version has inclined milling at the base of the teeth to generate centrifugal self-cleaning when used on muddy terrain, as well as lightening obtained through appropriate drilling.
AFAM uses the best steel alloys to produce its sprockets.
The teeth, with an exclusive AFAM profile, are hardened by induction to ensure maximum durability.

By choosing the ratios, 1 front sprocket cog is equal to about 3 rear sprocket cogs (the exact ratio is given by: number of rear sprocket teeth / number of front sprocket teeth).
The above stated, ratios have to be chosen in a way that a max. difference of 2 cogs is not exceeded. This way, you can always keep the same chain length. The Kawasaki ZX-10R Ninja is an exception: a rear chain with over 1 tooth more than the stock one cannot be used, since length of stock chain will not allow that. Remember that if you want more acceleration you have to mount a rear sprocket with more toothing, or a front sprocket with lower toothing. Ratios have to be necessarily and exclusively chosen by yourself. It is usual to mount a rear sprocket with 2 teeth more than the stock one, but that is however a medium choice which does not mean to be satisfying to everybody.
In a circuit, generally the right final ratio will be that allowing to achieve, at the highest gear, about 200 rpm more than the max power rate, always staying 200 / 300 rpm under the maximum rate the engine can reach. This way, you can take advantage of the trail of the driver who is preceding you.
Choosing the final ratio, remember that the bigger it is, the more the acceleration will be. But if it is too big, you will lose speed. If on the contrary the ratio is too small, you will lose acceleration and will not manage to reach the maximum speed.