650 head or 750 head?

does it matter what year 750 cylinders i use?

i havent seen that it makes a differance. Did all 750 4's come with a hivo style came chain?

You could probably look around mykawasaki; the diagrahms might help you decide if there is any differance worth worrying about!

The early heads (80-82 I think) had a combustion chamber that was around 1 cc smaller, and KZ750 heads have provision for a tach drive and the GPz750 heads don't.
Other than that it don't make much difference.

IMHO even with an 810 kit you won't be in the same ballpark with a newer 600cc crotch rocket :evil: (well mabe with a turbo ....)

if Kawasaki put bigger valves in the head you can bet they opened up the ports too (they did on the J model)
I think 1980 is when Kawasaki went to the hi-vo camchain in the 650-750 bikes.

that being said I have a 79 kz650 and a 84 kz700(same as a gpz750) head that needs a new home. (less retainers and buckets)

I wont give a price on here but u2u me for my e-mail addy.

p.s. if this is against the rules I will Edit the postB)

I think with an 810 kit and properly tuned you would have about the same hp as the 600cc crotch rockets, but unfortunately your bike will still weigh about a 100 lbs more, and that makes a "Lot" of difference
All the 750 fours used a HyVo cam chain, and the 650's started using them in 81 (some models).

Not against the rules IMHO

sooo are the cams/heads off other kaw 4's interchangeable? I wonder just how much choice there is?

any hotter factory cams than the gpz?

i got poking around ebay; is the zr7 zeyphr motor the same as the kz's? I spotted a head for one that looks identical to a KZ head (i know looks can be decieving, but its intresting none the less!)

Post edited by: hardr0ck68, at: 2006/03/05 14:35

If you can afford aftermarket cams, this will make a huge improvement in the stock 650 head. It's the best "Sleeper" modification you can get imho. Go over to Web Cams website and order their hot street cams and dual valvesprings.

I got 78HP with a Wiseco 700cc kit and these cams. I'm currently going to an 810 kit. I can keep up with most modern 600cc bikes in the tight twisties around here dragging the pegs all the way. In a straight line the bike pulls 120 easily and can be coaxed to 130 indicated w/ stock gearing.

Once cornering speeds hit 80mph the 600s are gone and if they use their top end they leave me on the freeway!

Still I've suprised a few ducati monsters at stoplights w/ my sleeper. It's a pretty even contest which suprises the hell out of them!