99 KX250, more bottom end?

[XRrider62]

I have 99 kx250 with an fmf Gnarly and 13/48 gears. I ride off road mostly and would like a little more grunt down low. Any suggestions? Thanks

 

[Yamadad]

Flywheel weight.

 

[DWreck]

Adding a tooth (49) to the rear sprocket makes a noticable difference.

 

[Britt Boyette]

Yes, it will but, if you ever do any 5th gear flying, you'll wish the KX was a 6 speed. That was me today, trying to find 6th.