altering sproket sizes

hey guys thinking of changing my sproket sizes on my zxr250 front sproket is 14 and rear is 48 teeth stock
on ebay there is a chain and sproket set available with these choices of sproket sizes
Gear Ratio
13 14 15 16 <front
48 3.69 3.43 3.20 3.00
41 3.15 2.93 2.73 2.56
40 3.08 2.86 2.67 2.50
^rear

what combination do u reckon would be best and what are the advantages/disadvantages of dong this modificaton
cheers

also any places you guys reccommend so i can see some prices as these are hard to find for this bike

i wouldnt go any smaller than 48 on the rear as your bike prolly accelerates slow enough as it is you could try going to a 13 on the front to make it a little more zippy

changing sizes means you either

a- lose acceleration and gain top speed

or

b- gain acceleration and lose top speed

On a bike that does not really have enough of either top speed or acceleration to start with, I wouldn't be prepared to lose either one. Leave it stock!

hahaha funny if i want to go fast i jump on my 600 this is my track/race bike and am using this to nail corner speeds not really worried bout goin 250klms+ down eastern creeks straight then slamming on the anchors (like some) so funnys aside if i want more acceleration what sprocket should i change n by how much also how much top speed do u loose roughly?

hahaha funny if i want to go fast i jump on my 600 this is my track/race bike and am using this to nail corner speeds not really worried bout goin 250klms+ down eastern creeks straight then slamming on the anchors (like some) so funnys aside if i want more acceleration what sprocket should i change n by how much also how much top speed do u loose roughly?

Tim, key the stock setting in at http://www.gearingcommander.com/ and then have a look at the effects of modifying the gear ratios.

Just a heads up, the majority of the acceleration gain is in 1st gear, which isn't that useful at most tracks on a 250. In the higher gears it's pretty much equivalent to shifting down a gear, whereas in first you do get an increase in thrust proportional to the gearing ratio. The only benefit in gears 2+ is that speed wise they become spaced a bit closer.

quick answer...

more acceleration = Up on the back... or down on the front...