Ok so as the title states, my 2010 sportster Iron 883 ended up with a bad crank. The piston connecting rod has play, I can lift it up about an 1/8 inch and also moves side to side plus the piston scored the cylinder wall pretty deep, so I figured before spending the money on the 883 I'd just swap it out with a 1200.
so that said I found a 2010 1200 with 10k miles for a great deal.
my question is (1) do I need to swap out the main harness or will mine be the same.
And (2) do I need to change out the computer or is the 883 the same?
can you think off any thing else I need to swap?

 

Should bolt right in. No need to swap anything else. You will need to reprogram the ECM for the 1200, preferably with a tuner like TTS or Powervision.

 

Ok so I have the ecm from the doner bike so I should be able to just swap that out then correct?

 

Your questions can probably be answered by simply checking a parts website, where you can look at part numbers for both 883 and 1200 models.