Famicom disk belt comes out

[Earthshaker]

Hi guys, today i got a Famicom Disk System and as usual I was going to fix it. I realized that it is a less common model (there are some differences about the box's style and some internal parts). However it's quite same.
But there is a problem.. i replaced the belt with a new one, but it always comes out after a couple of spin.. i checked everything and it looks fine, just the drive cog of the motor seems maybe a little bit higher. Have you ever had a similar problem? What can I do?

[zmaster18]

Check to make sure that your belt and white wheel don't have grease on it, and also that the white wheel doesn't have big scratches on it. These are the two main reasons why the belt falls off.

[Earthshaker]

I just checked and cleaned carefully.. But it still falls off.. I really dont understand why..
I read in an old thread of a guy who had a similar problem and he fixed it sanding the white wheel.. I am quite scared to do it, but I don't know what else I can do..

[zmaster18]

Yes, that would be the only other solution. It's very important not to scratch the white wheel when taking off the old rubber belt. If you use sandpaper or a file to smooth the surface of the wheel, it should stay on. I've used a file once to fix a big scratch I made and it worked well.

[Earthshaker]

ok, i will try it.
Thank you!