TOPIC:

Those forks are used only 2 years. 1981-82 on the “K” LTD and “M” CSR.    

Well sure, they *look* the same in ever aspect I can tell from the pictures, but that's not really a criteria I ever trust?

@Mikaw -- That sounds promising then.  I was pretty sure I had also only seen them on the K and CSR, so that's a good verification.  And the two I am specifically looking at on ebay are both labeled as coming from a 1981 (one from a CSR, the other just says kz1000) so it sounds like I should be in good shape.  The ones listed from the CSR have a little higher price on them, I'm assuming this seller saw something on the cheaper ones that justified the price difference so I'll just go for those.

Look at the last page of the manual I posted. It’s the rear cover. It will help you identify your frame. If it is a J1 I’d get forks for a J. The steering head angle is different between the J and m,k. A “j” with leading forks will not handle well. You have a shallower tube angle and the leading forks more trail, it will go straight but not turn well.  Think of a chopper. 

Oh I don't need to look at the cover, I already know all of this.  The original frame I got was a J1 (was verified by the VIN, along with multiple differences in the rest of the bike).  Previous owner had horribly chopped all the brackets off the back of the frame.  I happened to find a cheap listing for the rear majority of an LTD frame so I cut and welded the two together to make a whole frame again (but the front yoke is still from the J1).  This also gave me enough pieces to work with so I could upgrade every other part of the bike to the LTD bits, including the whole electrical system.

But this is also what SWest and I were discussing on the first page -- the change in the forks (which the previous owner did, not me, I just identified it as something that wasn't stock when rebuilding the bike) has not caused any issues handling out on the highway, and apparently this should actually make it handle better at speed.

So yes, this frame SHOULD have the type of forks with the axle at the bottom.  Instead I got a bike with the leading axle mount used on the LTD and CSR.  So I already know that style rides just fine even on the interstate, no wobble or shimmy or anything that ever worried me, so it seems like it would be best to stick with the style that I know works?

Yes it will go straight very well. The cornering will lacking. 

I'd like to know more about the original forks and the ones in question. Do they fit the J triple trees or was the whole front end swapped? On my bike 1 1/2" longer swing arm made the bike more stable but the steering is as it always has been. 
Steve

Hmm that's something I hadn't thought of.  I have no idea if the triple trees on my bike are the original ones or not.  However because of the frankenstein nature of my bike, I of course have the parts diagrams for both models. And lo and behold, the triple tree uppers and lowers DO have different part numbers, although there is visually no difference that I can see.  If you know of a way to tell them apart I can check tomorrow.

Just to clarify, with regards to the chassis, on my bike everything from the engine forward is from what I received as the original J bike (although of course I learned along the way that there were already mis-matched parts).  The frames were split just behind the engine cage as I thought that was a good way to keep less road-stress off my weld joints.  The engine itself is all from the J, the wiring harness was all from the K, and everything else was a mix to try and get it to the condition of an original K with all the amenities.  For everything where the part numbers matched, I just chose the one that was in better condition.

So yeah, there's a lot on the bike still which I have no idea where they originated from, but they appeared to be correct from the information I could find.

I am not sure how much of the geometry difference between the K and J is in the frame. The K forks are 30mm longer than the J which will influence the "rake" and "trail". I do know that the 750 ltd with "leading" forks has less "offset" in the trees than the J equivalent. Worth checking the manual to see if the same is true of the 1000. If required you could probably sharpen the steering by pushing the forks through the trees a little

J = rake 27.5, Trail 99mm
K = rake 29, Trail 105mm

Mikaw wrote:

J = rake 27.5, Trail 99mm
K = rake 29, Trail 105mm

Appreciate that but won't the "shorter J forks" and possibly different "offset" in the trees contribute to at least some of the difference ?

That’s all the FSM discloses. I don’t know personally if there is offset in the trees and if it’s different between the J and K.