Part was screening to front frame under gas tank. Two wires red and green. Melted one side nowmlighta don’t work. I’ve searched but electrically and schematically ignorant. Any help very appreciated in Identifying part. 

1984 xt250

thanks!

It's the rectifier. Changes AC to DC for charging battery. Just fit a new one & she'll be good. Likely a white wire in & a red wire out with spade connectors so can't get it wrong. I'll find ya one.

Yes, rectifier.

Insert the number only into the link search bar. I'm hopeless at direct linking ebay, they stop me somehow.
eBay item number:125326993068
www.ebay.com/sch/ebayadvsearch

I see my link is a slightly different shape so be sure you have room above the screw hole or it might hit the frame. Or step the mount down. Should be plenty out there to fit.

1984 XT250 in US has regulator/rectifier... so might be from another country or an earlier model?

Earlier model used this rectifier, still available from Yamaha or from aftermarket suppliers: www.partzilla.com/product/yamaha/1M1-81970-60-00

I missed the fact that it's "84 [thinking about "80] but she's sure melted!!
Looks like the rectifier type finished with the K model in "83--but don't matter. Yours should have a single wire regulator as well hidden somewhere. Doubt that's why the rectifier got fried & likely just a corroded connection on the in or the out--likely red & just gave up. Might be wrong.
#12 www.partzilla.com/catalog/yamaha/motorcy.../xt250k/electrical-1

Thanks so much! That’s close as I got for the part and I appreciate your follow up and the links! Will
let ya know how it goes