Hi people,after riding jap sports bikes for the last 30 yrs ,ive finally  turned to the dark side and bought a 2009 Sportster.The bike I purchased is plated as a 883 xlc,however,the fella i bought it from reckons it has a 1200 kit .There is nothing that I can see that supports his claim.Is there a way of telling if it is a 1200?It does go like a shower of shit when you give her a good twist of the wrist,exceeded my expectations,even with the wife on the back.So if anyone can give me a bit of input it would be much appreciated.

could put it on a Dyno, would tell you quick enough, one power run.

You can actually measure the diagonal of the cylinder.
Jack up the rear wheel, take out both spark plugs
put the bike in 5th gear. Rotate the rear wheel
until the piston is at bottom dead center, BDC.
Use a wooden dowel or chop stick to feel when the
piston is at the bottom.

Then push the bottom end of the stick to the far side
of the combustion chamber and mark the end of the stick
where it hits the upper lip of the spark plug hole.
This is the diagonal of the chamber and it will be different
for a 1200 vs. a 883. Your measurements might be close to this.

For a 1200 it will be about 5 7/8"
For a 883 it will be about 5 1/2"

Thanks for the info people,im sure I will work it out one way or another,but just another thing ,would anyone be able to give me any preferences on what type of oil to use?

Search the forum.  The "what oil" question has been done to death.

Pop the cutch see how good you can fishy that will tell you, nah but a dyno will work my 1200 conversion got 89hp that was a good tune should be around there.

i did the search a few weeks ago,couldn't really pin it down one brand .type or weight,everyone seems to use something different.I ended up running with Harley Davidson oil for now.was going to use penrite mc4st 20w-50 but couldnt find much on it.

lol exactly.   penrite is ok.   my bike runs quietest on mobil 1 vtwin.

thanks killer,I walked away confused at the end of it none the wiser ,thats why i just went to my local HD dealer and bought their brand

if it has 883 heads on it then it will gain a squish band around the perimeter of the combustion chamber . do a search on conversion  , all good stuff HD should have done to the sporties

https://www.hdherd.com/forum/motorcycle-related-topics/evo-sporties/161-sportster-heads-differences