Larger rear sprocket

[17-CB-002]

I've done it both ends. One down on the front and two up on the rear.
With my engin mods making just shy of 100bhp it could pull more but I like to be able to use all the engine has. I can rev it out in 4th and still keep my licence... just!
I find 5k rpm + a great and harmonious place to be and usually keep the engine moving.
If I went back a tooth or so then I'd probably be able to get a few more tenths of a second on my 1/4 mile times, but it feels great and that's what it's all about for me.
6th still feels like an overdrive to me but now pulls more keenly when I do need to zip past something.

I like your idea, just to reconfirm:
Do you have the part number for the front pinion & rear sprocket is 206909.
Do you need to replace the original chain?
Will that fit a 2017?
Thanks