KZ650 CSR/Ltd frame and front fork differences

To be honest there is only 2 degree's difference between the two so with the shorter stock 650 (non Ltd/CSR) front end and an 18" wheel you will get most of that back without the cost of a frame swop and any title hassle that goes with it

Yes if the only difference is the 2 degrees and the headstock is not also placed higher in the frame, then I agree. I can find those 2 degrees elsewhere.

I was just in the garage so I measured and confirmed the 29 degree castor. What I also confirmed was just changing to a 18" rear would get me to 28 degrees so a little bit of extra lowering at the front, or an 18 inch front together with a bit longer shocks in the rear, then I would be "back" at the 27 degrees of the "normal" frame.

Just to add some more to the discussion, here is some data re length of the inner tubes for the 650s. This was posted on the old 659 info site, not by me and I can not speak to its accurateness or not.
It lists the part numb, models used on and length. This was all posted so no info on the H models, but I think they (H models) had the longest.

all are 36 mm diameter
44013-062 (B1/B2 - 588 mm long), 
44013-1005 (C2/C3 - 588 mm long) 
39093-1063 (F2 and SR - 591 mm long)
 

You may be able to fit the shorter tubes into your original leading axle lowers (you would need to shorten the spring spacers by the same amount of difference in the tubes) you could then keep the stock tree's