As the other members have already stated, you do not want to run such a high amp device through the stock wiring. Something somewhere will most likely fry, and that would suck. Do the job right and install the relay. You want the power drawn directly from the battery (fused, of course, either inline or through a fuse block), try to avoid running any electrical farkles through the stock wiring.
2008 DL650 a.k.a. Road Warrior, member #16 of the Flat Black Club
2009 Aprilia Tuono 1000R a.k.a. Silver Thunder