[kubas9311]

Hi! I have problem with my crfx, when i bought bike, it has new tires. when i drove, i saw that chain destroyed tire. I bought new chain and sprockets, but
did not help. Tire size is 120/90 Mitas C02. My friend have this same tire and he dont have this problem. Where is the problem? Please help me, i dont have idea. Regards

[JimDirt]

Welcome to the site

It most likely is that you are using a O'Ring chain with a non offset front sprocket , the O'Ring chains are wider and will sometimes hit the chain if the slack is too loose , or if a standard sprocket is used

So first things first

Check that the Axle is adjusted squarely/evenly so as not to make the chain side be shorter than the brake side, this will ensure that the wheel itself is straight

Make sure the chain is not too loose , as this will allow side to side slop (but do not make it too tight)

Make sure that if the front sprocket has a offset , to make sure its sticking out not in

If all is correct and it still hits , then just trim the side of the mud flap so it clears the chain (trim it to or just past the wear/cut marks) , it won't hurt anything and a lot of do it

[Leardriver]

And...although I prefer to run a 120 width tire, they are not all the same width, and the stock 110 width is more predictably narrow enough to avoid this.

[kubas9311]

Yes, I use xring chain and oryginal sprockets. The distance brake and chain side is this same, front sprocket is rotated, all is ok...
Later upload photo, thanks

Edit
The original tire width is 140, in the manual