I have a D413 buggy I bought used and got a Hobbywing V2 Blue ESC and a 6.5 Hobbywing V10 motor Futaba PX4 with a R304SB reviecer along with a digital Savox servo, about 1 minute in the negative wire on the ESC melted, borrowed a Tekin RSX and no issues the rest of the day. Replace the ESC With a Reedy 1000Z same issue same result with the RSX, put a Reedy 510R in same issue any ideas or thoughts would be greatly appreciated.

Loose or partial connection somewhere? Seems weird didn't happen on the Tekin though. Maybe wire is almost busted inside and being bumped around its making/breaking contact internally?

change the 6.5 to a larger motor as in 8.5

The biggest thing in my opinion would be the size of wire used, on my losi scte I would melt that wire off of the rx8 esc, went to a different 12 gauge wire brand and the problem went away, I had been using the viper stuff, then tried some tekin and Novak, finally settled on deans wire