Differences between 79 and 81

Hey guys.

Wondering what the differences are between the 79 and the 81 KZ1300.

I have an opportunity to buy a running 79 for $1200. The best part of the deal is it comes with a big bore kit that the owner didn't bother to install. Still in the box.

I know the ignition system is different but I'm wondering how viable it would be to keep my 81 as a parts bike and part out a few things that I don't need.

Are the head and most of the motor parts cross compatible? Drive train? I'm fair certain most of the cosmetic parts will cross over.

The major differences between the big KZ motors was the location of the ignition pickups, but I'm unsure when they switched. The A1s and A2s had the pickups right behind the cylinder block on the right side, ran off the water pump secondary shaft. The A3s moved the pickups to the crank, but I'm not sure what side- right, maybe?

Problem is, I don't know when the switchover was. '81 is right there in the ballpark as to when it started happening. The '81 may have been when it happened.

As far as I know, everything else can be swapped between the bikes no problem. A vast majority of your '81 parts will bolt right up to the '79, and vice-versa. There are a couple differences in gas tanks, airbox covers, and grab rails, but all are pretty much cosmetic.

My only advice is to keep the correct carb set with the correct engine. Again, I don't think the top end changed much, if at all, but if you have the right sets already, there's no reason to temp fate and mix them up.

Thank you for getting back to me as fast as you did. I'm due to go look at this bike as soon as the wife comes home from work.

The owner says it smokes and this is why he bought the big bore kit that he never installed before he lost interest. I'll let you know how this turns out in a few hours

Well... I went and bought it. From a purely cosmetic perspective it is much better shape than my 81. The seat is mint so that saves me $300 right away to have it cut down and re-covered. It has a couple of other pieces I was looking for such as the front fork brace and chrome rad cover. The front forks are in far better shape and the fork seals don't leak. Stainless lines in front is another plus.

It started right up and I drove it home. As he indicated, it does smoke so good thing it came with a big bore kit and all the gaskets. The pistons are labeled 64mm.

One crappy thing... the starter switch is baked like my 81 so it will need to be rebuilt or replaced. The rear brake don't work so it is a good thing mine are great.



Here she is

OOooooo.... looks pretty sweet!

Not sure if they're included (looks like they might be), but while you got the motor tore apart to big-bore it out, be sure the valve stem seals get changed as well. If the motor smokes all the time bad valve stem seals probably AREN'T the reason why, but you can only change them by pulling the head. May as well get it done while it's apart.

(You'll also find that certain big bore piston parts (rings in particular) are actually SUBSTANTIALLY cheaper than standard size ones. For whatever reason. While rebuilding mine, I actually seriously considered popping a big bore kit on it, if only to save me a bit of cash.... O_o )

Absolutely! When this comes apart I'm going to do it all right so it stays done. I'll have the head checked while its off etc.

I'm feeling pretty good about this. I got a nice deal today which really offsets my initial disappointment. Saves me a ton of cosmetic work.

Of course I also have my brand new DG header which I wouldn't dream of putting on until I finish with this over the winter.