What size are the standard front and rear sprockets for the 2KR? I can't seem to find it using search... <!-- s:alcoholic: --><img src="{SMILIES_PATH}/icon_all_coholic.gif" alt=":alcoholic:" title="Alcoholic" /><!-- s:alcoholic: -->
Yep, 17/55 is stock. You can quite happily go up to 17/57 if your intending on keeping the bike around town or below 160km/h. It gives it a bit more zip off the line.
On the topic of giving it more "zip," are there any differences between going less on the front rather than more on the back?
Yes, yes there is. Dropping 1 tooth from the front is about the equivalent of adding 3 to the rear. However in dropping a tooth from the front your reducing the turning radius of the chain around the front sprocket, which will reduce chain life. Adding a few teeth on the rear (anywhere up to 6-8 is fine) will increase the turning radius of the rear, which will have no adverse influence on chain life. The only downside to running a bigger rear sprocket is the increased weight from both potentially a longer chain (only a couple of links at most) and the larger and therefore heavier sprocket.
With the lack of power of the 250's, an alum. sprocket shoud be fine. On the larger/higher HP bikes stick with steel.
Usually about $70-90 for the pair (front and rear). Some are cheaper, some are more expensive... usually depends on if you get bling colour ones or just boring steel ones.
