48t rear sprocket
 

Has anybody changed their rear sprocket to 48t?
What is the expected performance like?

Nope..because a 14 front gives about the same ratio...
1 tooth on the front = 3 on the rear...

As above. 14/45 is the same final drive ratio as 15/48.

However, the front sprocket and chain will last longer if you stick with a 15 and go 48 on the rear, but then on the other hand you'll need to buy a longer chain - you win some you lose some!

You do need an extra link or two with a 48 even if you go down to 14t on the front

Thanks for all the food for thought. As i have had problems with yamahas weak stock chains before i am going to upgrade the sprocket and chain in one swoop. What i am concerned about is the bikes performance. Are at low speed. Not worried about high speeds as i live in the worlds slowest country (the frustration kills me though)