upgrading to a j model head

so thanks to the kzrider classifieds, I have purchased a new head for my KZ1000 police bike. It's off a j model and includes the necessary cam conversion tower and ended up being less than I expected to pay to get new valves. The guy I bought it from said that from there all I would need is a new valve cover gasket, cam plugs and valve reed covers. Can anybody else think of something I might need? Will the installation of the cams be similar? Meaning, will there still be the little ">" mark?
Is there anything else I should know about this upgrade? I just don't want to foul this up this time! :laugh:

a set of 10.25:1 pistons would be a good start since your compression is fixing to drop abot 1.5 points!:laugh:

PLUMMEN wrote:

a set of 10.25:1 pistons would be a good start since your compression is fixing to drop abot 1.5 points!:laugh:

OOOH...thats doesnt sound good!...

i think it is 2 points. 2.5 with a gpz head.

Cylinder head.. J model head has larger valves and ports. This head can be used on earlier style cylinder and lower end by installing APE #CCIA cam chain sprocket adapter in head . How to tell which head you have.. Early style heads have four factory drilled and tapped 6mm holes in the center to bolt in cam chain idler gear. Z1 900 heads have 6 mm exhaust studs, KZ1000 8 mm. On the J model head, the four cam plugs at the ends of the camshaft areas are bolted in, on the early style head, they just push in and the valve cover holds them in. The J model / '81-'82 GPZ1100 cylinder head has a larger combustion chamber than the early style head. When these heads are used on the early style motor, a compression ratio drop of about 2 full points can be expected.

More info on the differences between the two motors can be found at www.aperaceparts.com/tech/techkz1000.html

I noticed that Z1 has a nice set of reed covers, without the hose nipple, in their catalog. Seems there is something new in the catalog every time I look.....chris3

so I'm looking on APE at pistons... which part number am I gonna need?

id say a 1075 10.25:1 kit would work fine;)

I think APE has a piston kit (probably more than one) specifically for the J model head on a early 1000. If you can't find it PM APE Jay, or give APE a call.

So I've decided to just keep the pistons stock for now... I'd rather just get the damn thing running before I throw another 5 or 600 dollars at it
Now I want to ask about jetting.
Does this j-model upgrade change my jetting at all?
I have pods and a stock exhaust on it.
Anyone?

I'm not sure it will run at all with 6-6.5:1 compression, and if you put a J head on a stock 1015cc motor, that's what you'll have.

I'd like to know about it if you do get it to start.

From the link I posted earlier:

The J model / '81-'82 GPZ1100 cylinder head has a larger combustion chamber than the early style head. When these heads are used on the early style motor, a compression ratio drop of about 2 full points can be expected.

Stock is what, 8.5:1?

Just looked, Zedder says it 8.7:1, so your compression ratio after installing the J head should be 6.7:1.

I'm still curious about whether it will even start.

.

why not fix the original head?