Well lots of folks have told you how and why your Iron can't do the trip... Not everyone feels that way. Take a chance, prepare as best you can and then get out there and do it...

ADVRider forum has a road report from a couple riding a '93 Sportster from Wisconsin to Puerto Toro southernmost town in South America. there's also one from a guy from LA who rode an 08 Road King to the end of the Alaska Highway and then turned around and rode the same bike from the US completely through Mexico, Central and South America to Patagonia. By himself much of the way with no map and no support vehicle...

 

Go for it. The OL and I did 217 miles from Johannesburg to Cape Town (to the southern most tip of Africa) in the winter on the Nightster. We froze our asses off and packed the bike like a mule...but we did it and it was the experience of a lifetime. I want to do East to West (Mozambique to Namibia West Coast) next. It CAN be done...just take it easy and the Iron should be fine.