changing sprocket size affect mph/ odo?

On a te 449?

No- the speedo pickup is on the front wheel. However, on your bike the magnet has been know to jump out of its proper location on the disc brake rotor. If so, you can usually find the magnet stuck somewhere on the rotor.
good luck.

Lol yes I've all ready experienced this bought the bike brand new and the speed magnet was missing

Yeah, my magnet was missing too. Went back to dealer and had them pull one off floor model.

Just out of curiosity where did you buy yours from? Got mine from berts mega mall covina

Yep- on my kid's '12 TE511, that magnet jumped out many times. I found it sticking to the rotor every time but one, and that time I found it (closer to the hub? In the caliper? CRS).

I finally epoxied it in and it's been good for 2 years. And it never has been an issue on my '14 310.

[just thought of something: seems to me that (if you're epoxy-adverse for some reason) you could stake the aluminum holder over the magnet with center punch 3-4x's around the edge. If the holder is a tight enough fit to begin with, that is]

Super-glue works fine as well, 2 years trouble free after gluing mine in.

Bought mine at Bert's also.

No wonder why I saw a 12 for sale with only 200 miles on it haha.

Couldn't beat that sales price from berts got mine for 7360 otd

Will do the tps reset. Definitely going to send my ecu to zip ty. I was told that some 449 ecu s are locked and can't be flashed?