1981 KZ1000J questions

Lack of cash has kept me from doing much on the bike this Summer, but I've still been looking for inspiration on how I want to really build it back up. I like the street look, but it's just too 'common'. I ran across this picture today and it has me thinking, but there are some questions...

I have a 16" rear wheel, but I see an 18" was available, and I kinda like the look of the same-sized wheels better. Does anyone know if this wheel would be a straight bolt-on, or if I would need to replace the swingarm or brakes or anything else? (Also now I'm curious if this bike actually has the larger rear, or if it's just an illusion of the photo)

I like the look of the duck tail without the fender, but the one from the 70's KZ1000's feels a bit long to me. The tail from the KZ650 has a nice lip at the back and appears shorter. Is it actually shorter? (And yes, I know that frame is different and I will have to make mods to add a tail on mine.)

That seat... I've never seen anything like it. It gives the look of a "badass biker" but it's a double seat. I'm not so sure how that thin of padding would feel on the rear after a couple hours of riding, but it has me considering what it would take to make my own seat pan... Anyone have tips or links on making a custom pan? Anyone seen similar seats for sale that I might buy?

I believe z1 enterprises sells that seat.

as to making your own pan, not hard, did it twice, once on my 81 J and once on a 77 gs750. Just take the part jn pieces, cut bend and weld I used 16ga steel for mine, 18ga would be more appropriate tho.

Really, that thin? I have a bunch of pieces of scrap steel laying around, I might just have to put one together and see if I like it. I've had a bit of practice shaping steel for things such as armor, so a pan ought to be easy.

Can you use a heat gun to help shape the curves of the vinyl? I've made seat covers in the past, but after a few years (even with marine vinyl), it starts tearing apart where the stitches run through, so it would be nice if I could shape it better without having to pull it so tight.

Are sure the bike in the picture is an '81 J? Looks more like a 1977-1980 KZ1000 LTD.

I don't see anything in the picture indicating it's a J model.

Here's what a "J" looks like:

No, the bike in the pic is most certainly NOT a J... but MY bike started out as one. My frame is now a mix of a J and a K, but I'm still at the stage where I can make changes before getting it painted.

Yes that thin, and yup, the bike that shadowdragon is talking about is as much a J model as a cafe'd ELR is an elr.

If you shape the pan well and support it well, thin gauge stuff holds up nicely. The factory pan isnt much more thanmpaper thin really, part of why the hooks that hold the pan rot off so easily

Can anyone tell me if the KZ650 tail cowl (I think it was a 77-79 650B? It's the duck-bill style, not the squared-up type) is shorter that the one from the KZ1000, or if they are the same length? I'm mainly interested in the actual length between the lip where the seat fits and the rear of the tail (basically the length of the part that shows behind the seat).

I've seen references here that some people have fit the 650 cowl to a 1000, but I can't find any pictures of how it turned out.

Screw it, I bit the bullet and grabbed a 650 tail off ebay. I'll play with it when it gets here, and if I don't like it, I'll just resell it. I'll definitely have to make my own seat if I want to use the tail, so we'll see how it goes.

[EDIT]
By the way, in case anyone finds this thread in the future, I did find some pics of one person doing a fitting of the 650 tail on an 80's kz1000. Not a lot of details, but the pictures definitely help see how it fits (which is very well!)... Direct link here...

Received the tail today. The size and shape are just what I expected from the pictures I saw online (sometimes pics can be deceiving though...) so I'm really happy with it. I guess some people will be upset, but the first thing I did was take the angle grinder and start cutting the inside of the front legs so that it would fit around the brackets on my frame. I guess considering the price and the number I see on ebay, there's no shortage of this particular tail though. I got it trimmed up to fit pretty decent, I just need to add some brackets to bolt it in place. Then the big step comes -- I'll have to take the seat apart and chop up the pan to fit into the tail. I'm thinking I may just get all new foam to shape as I like, and I still have enough marine vinyl to make another seat.