How do you Square up the axle on a 2006 Harley Davidson sportster it has no data marks

Hi Marco. Put the exact words you used into google and you'll get dozens of results including videos. Oh and welcome to the forum

Yeah, welcome to the forum.

https://www.youtube.com/watch?v=vuwGM0Xx378

You need a gas welding rod and the instructiosn on the Internet.

loosen the wheel nuts so the point is at the top/bottom, I measure from the inner of the adjuster (closest to front wheel) to the midpoint of the wheelnut (the point of the nut)

Has worked well for me, there are probably a dozen ways you can do it.

One trick I learned from dirtbikes is slide the wheel in, then jam a spanner or screwdriver in the chain/sprocket join and it centres the wheel nearly every time.

Not the best idea with a powdercoated pulley wheel.