WANTED! 83 GPZ 750 ZX750-A HEAD & VALVE COVER

Anyone know where I can get a nice complete 83 gpz head with cover?

Depends on what you mean by "complete" and "nice".

"Complete" as in with cams"?
"Nice" as in not needing to have the valves lapped in, or possibly new valves guides (which requires grinding the valves and cutting the seats)?

I have a spare 83-85 GPz750 head or two, but I haven't disassembled them to check the valves or guides, and I have a couple of cam covers. "But", there are only three things different about the 83-85 GPz750 heads vs the KZ750 heads (I have a couple of those as well, but I won't sell them).

(1) Minor porting on the GP head, but you can easily port the KZ head to match.

(2) No provision for tach drive on the GPz head.

(3) the fins are shaped a little differently on the GPz head.

I'm building a hot rod 750/810 motor (waiting on pistons to arrive), and it will have a ported KZ750 head on it.

Oh yeah, one other possible difference, I have read that the 80 KZ750E and the KZ750H models have slightly smaller combustion chambers, which means slightly higher compression, but I haven't measured any myself so I can neither confirm or deny.

Post edited by: steell, at: 2008/03/01 11:47

steell wrote:

I'm building a hot rod 750/810 motor (waiting on pistons to arrive), and it will have a ported KZ750 head on it.

Who is doing your head work Mr Steell? I'd be interested in the results

Post edited by: Lorcan, at: 2008/03/01 12:37

steell wrote:

I have read that the 80 KZ750E and the KZ750H models have slightly smaller combustion chambers, which means slightly higher compression, but I haven't measured any myself so I can neither confirm or deny.

If you have the means, I wish you would. It'd be nice to finally shed some light on this particular topic...

So, should I just port my stock head? I already have the 810 kit, what do you recommend for camshafts? I still want to have a reliable streetable bike, maybe stage 2 cams?

For $388 plus shipping Megacycle will regrind your stock cams.

#471-00 is real close to the stock GPz750 cams (354 lift 254 duration at .040" for Megacycle, 354 lift 250 duration for GPz cams according to Megacycle)

#471-70 would be the next step up at .380 lift and 256/261 duration (intake/exhaust).

#471-90 is probably the max that could "possibly" work as a street cam, .428 lift 264 duration, requires cylinder head clearancing. Megacycle calls it their "Superbike Racing Cam", so it's probably pushing the envelope to call it "streetable"

Web Cams will also regrind your cams, and I'm sure they have compatible grinds.

GPz750 cams are a lot cheaper, but you have to use an electronic tach as they don't have a tach drive, and some have a smaller base circle (which may help if you have to grind the valves anyway).


And of course there's always oversize valves, professional porting by APE, FBG, Larry Cavanaugh, and others.
How Fa$t do you want to go??
All it takes is bushel baskets of money

Did I mention EFI? :evil:

Post edited by: steell, at: 2008/03/01 14:16

guitargeek wrote:

steell wrote:

I have read that the 80 KZ750E and the KZ750H models have slightly smaller combustion chambers, which means slightly higher compression, but I haven't measured any myself so I can neither confirm or deny.

If you have the means, I wish you would. It'd be nice to finally shed some light on this particular topic...

Doubtful that I will get around to it for awhile (if ever), I have three bikes, four motors, two (at least) EFI conversions, and a bunch of metalworking projects to get done

And I need to do something about income, since I am currently unemployed (need the "bushel baskets" of money)

Post edited by: steell, at: 2008/03/01 14:42

There is a GPz750 head with cams on eBay right now.