stock chain?

I'm looking at upgrading my stock 43 tooth to a 48 tooth sprocket. I haven't decided on a brand of sprocket or material I'm going with but I"m curious to know if I will be safe with the stock chain or if I need a new one. If I do need a new one how many pins will I need to cut it to? Thanks.

You will certainly need a longer chain.
Not sure of how many links it will have to be.
You can always buy a 120 link chain and shorten it yourself.

Looks like you need a 112 Link chain

https://wr250rforum.forumotion.com/t5-chains-and-sprockets

The stock chain is a DID 520V, if its fairly new you can add a few links to it so the bigger sprocket will fit.
Theres a few different pin sizes used on DID chains make sure you get the right sized links. The 520V has the smallest pin diamater of all the 520 DID chains.
I had a piece of kmc chain that was the exact same size left over from another bike and added 6 links to the stock chain with two DID 520V rivet links. I have 13-50 gearing with a 114 link chain now.