83 KZ750 Spectre - Possible interchangable head

Hey all, I need some expertise please! I've searched the forum and not finding what I need.

The question (short story below): For my 83 KZ750 Spectre, what are ALL my options for full head & valve cover replacement as a straight bolt on (or minimal work)?

Here is a quick story on the bike I just acquired. Bought a 1983 Kawasaki KZ750 Spectre with a hole in the head for dirt cheap. Upon taking the motor apart, I have found that one of the exhaust cam bolts likely started to come off, started grinding on the head/valve cover, then blew out the front of the head and left a big hole (picture attached).

So I am now in the hunt for a head/valve cover. As you can imagine, finding a Spectre specific head locally is not very easy. So because of this, I'm trying to find out if I have more options. I have read that the compression is different between the Spectre and the regular KZ750, so I'm assuming I can't just bolt a regular KZ750 head on my Spectre Cylinder engine...if wrong, please correct me!

So in summary again, I have a good bottom end & good cylinders. Can I bolt any other heads on my Spectre? Any info will be helpful.

I have seen a few on ebay and parts engines on craigslist. I would keep your eyes open is all they are out there.

Hold onto those camshafts. I understand that the Specter and GPz cams from that year have good lift and duration. In fact, could you please measure the lobe height, from the back side or base circle of the cam, to the very top of the lobe? I am considering changing cams in my 650, and would like to know what to expect. Thanks. Sorry to divert the topic.

If you have an electrical tach, then use the 83-85 GPz750 head, if mechanical tach then use any KZ750 head.
Compression ratio changes are due to pistons used, may be slight difference in chamber cc's, but not enough to notice.

I just checked kawasaki.com parts diagrams and it says the 83 Spectre uses the same cams as the other KZ750's, but the same pistons as the 83-85 GPz750. Cylinder head appears to me to be the same as the 83-85 GPz750.

I have a 83-85 GPz750 head, PM me for info.

Edit:

The following models all use the same exhaust cam (again, according to kawasaki.com parts diagrams)

KZ700-A1 (1984)
KZ750-F1 (LTD Shaft) (1983)
KZ750-L3 (1983)
KZ750-N1 (Spectre) (1982)
KZ750-N2 (Spectre) (1983)
KZ750-R1 (GPz) (1982)
ZR750-C1 (Zephyr 750) (1991)
ZR750-C2 (Zephyr 750) (1992)
ZR750-C3 (Zephyr 750) (1993)

And the following models all use the same intake cam.

KZ700-A1 (1984)
KZ750-E1 (1980)
KZ750-E2 (1981)
KZ750-E3 (1982)
KZ750-F1 (LTD Shaft) (1983)
KZ750-H1 (LTD) (1980)
KZ750-H2 (LTD) (1981)
KZ750-H3 (LTD) (1982)
KZ750-H4 (LTD) (1983)
KZ750-L3 (1983)
KZ750-N1 (Spectre) (1982)
KZ750-N2 (Spectre) (1983)
KZ750-R1 (GPz) (1982)
ZR750-C1 (Zephyr 750) (1991)
ZR750-C2 (Zephyr 750) (1992)
ZR750-C3 (Zephyr 750) (1993)

,

I would do a cross reference of head gaskets to see what part numbers line up.


sent 5 minutes ago via hand held

donthaveakawman wrote: I would do a cross reference of head gaskets to see what part numbers line up.


sent 5 minutes ago via hand held

Then it's a good thing you're not the one doing it. :whistle:

steell wrote:

donthaveakawman wrote: I would do a cross reference of head gaskets to see what part numbers line up.


sent 5 minutes ago via hand held

Then it's a good thing you're not the one doing it. :whistle:

ditto, I agree it is a good thing I am not the one that has to do the dirty work.

donthaveakawman wrote: I would do a cross reference of head gaskets to see what part numbers line up.

I see a heap full of matching head gaskets, but I can't imagine all would work. Has anyone ever successfully swapped the head onto a Spectre from say the standard kz750? As much as I want to just try, I don't want to put money into and then have some clearance problem that does more damage.

At this point I guess I'm just in the hunt for a 82/83 Spectre head...or a full motor depending on what I find first and the cost.

I would think a regular 750 head would work. a 650 head might even work. there are the small fours 550,650,750 and the big fours are the 900 and 1000 (1100?) a 550 head would definitely not work and the big four head would not work.

SpectreCafe wrote:

donthaveakawman wrote: I would do a cross reference of head gaskets to see what part numbers line up.

I see a heap full of matching head gaskets, but I can't imagine all would work. Has anyone ever successfully swapped the head onto a Spectre from say the standard kz750? As much as I want to just try, I don't want to put money into and then have some clearance problem that does more damage.

At this point I guess I'm just in the hunt for a 82/83 Spectre head...or a full motor depending on what I find first and the cost.

You have a reading problem or something? I just told you what to use in my previous post.

Want me to lie to you and say I have a 83 Spectre head then send you a GPz750 head? You couldn't tell the difference anyway.

According to kawasaki.com parts diagrams, all the following models use the exact same head gasket, that should tell you something.

KZ650-B1 (1977)
KZ650-B2 (1978)
KZ650-B2A (1978)
KZ650-B3 (1979)
KZ650-C1 (Custom) (1977)
KZ650-C2 (Custom) (1978)
KZ650-C3 (Custom) (1979)
KZ650-D1 (SR) (1978)
KZ650-D1A (SR) (1978)
KZ650-D2 (SR) (1979)
KZ650-E1 (LTD) (1980)
KZ650-F1 (1980)
KZ650-H1 (CSR) (1981)
KZ650-H2 (CSR) (1982)
KZ650-H3 (CSR) (1983)
KZ750-E1 (1980)
KZ750-E2 (1981)
KZ750-E3 (1982)
KZ750-F1 (LTD Shaft) (1983)
KZ750-H1 (LTD) (1980)
KZ750-H2 (LTD) (1981)
KZ750-H3 (LTD) (1982)
KZ750-H4 (LTD) (1983)
KZ750-L3 (1983)
KZ750-N1 (Spectre) (1982)
KZ750-N2 (Spectre) (1983)
KZ750-R1 (GPz) (1982)
ZX750-A1 (GPz 750) (1983)
ZX750-A2 (GPz 750) (1984)
ZX750-A3 (GPz 750) (1985)

That list is accurate as far as it goes, but the later ZR750 head gasket works and is the one recommended for the 750 Turbo motors (MLS gasket).




.

If Steell has the cam's also buy it from him.
The GPz cam's have a smaller base circle then
standard KZ750 cam's.

Plus the gain it power you'll really like.

I did catch the GPZ head option, and I'm looking for that as well...just failed to mention it in my last post.

Secondly I'm trying to avoid a sight/unseen purchase if at all possible. I see options on ebay and other sources, but at this point in time I want to avoid that. There may be a day that I open up to the idea depending on my success for a local option.

Thirdly, matching head gaskets may give me an indication that it will bolt up, but doesn't guarantee I won't have any other issues right? Clearance with my Spectre pistons with another top end? Compression change...good or bad shift in performance? Am I crazy to think that? I suppose I'm just paranoid given I haven't heard from anyone who has done this yet...regardless of the probability of it being done before (which I would assume is high). I guess I just wanted piece of mind going into this journey.

BTW, I'm headed down to a place called Bent Bike in the Seattle area today. They had a KZ750 head (full...had cams/cover/valves/etc) last time I was there for $125. If it's still there and I don't see any Spectre/GPZ head, I'm going to give her a go!