sprocket ratios / engine power

[JACK STRAW]

My son is looking for a little more top end. the 6* key did make it rev faster and now his sprockets are shot so he wants to change his gearing.
I have read the diffrent threads on sprockets and ratios and the jist I got out of it is if i go with a 15/38 combo compared to a 13/33 the speed will be a little faster because of less spinning mass but the 13/33 combo will wear out faster. How much faster will it wear 2 to 1 ???. We are going to run an x ring chain. What is the highest ratio that our motor configurations can handle without bogging them down. I am running case savers.thanks

[Mtndew99]

Go 15/36 or 15/37

[odog]

if your stock ratio is 14/39 then 15/39 or 15/38 is what i will try but your bike acceleration wont be the same it will take a little longer to get there but you ll like the top end power differance if you have enough engine to get you therer.

[JOHNDOE83]

I wouldnt go past 15/38, try a 14/36 or if you already have 13/33 just try 14/33 for a mild motor like yours with 20in tires 15/36 would need a lil more HP to fully rev out 5th gear.

14/36 is a Excellent combo for any 400ex motor, 14/33 with a few mods should pull fine.