KZ650 to 750 question

If I have a 1977 KZ650, and I happen to get a complete 1977 KZ750 upper, cylinder, pistons, head.... other than I guess opening up the case for the cylinders to fit..... am I looking at any other "problems" or issues?

If your 750 parts are from a 4 cylinder, they are 1980 and above model years.

I understand this is doable, but I have never done it. I know the cam sprockets and chains are different.
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Apeman, check this link Ebay Link same year as the KZ650, so I wasn't sure. Thanks for the reply though, let me know!

Post edited by: steell, at: 2006/08/16 19:13

If you swap to the 750 top end, you will need to swap cam sprockets with your 650. the early 650s use a roller chain, while the 750s use a hyvo. using the 650 "roller" sprockets on the 750 cams is how you make your crank work with the 750 stuff. and yes you will need to enlarge the holes in the case to fit the larger sleeves, its not hard.

Its pretty easy to just drop the whole 750 into the 77 650 frame. I happen to have one sitting here just like your looking to do 77 650B frame with a 80 750LTD motor that Im in the process of parting.

I saw that on eBay and had a good chuckle, and the same for the 81 KZ750 twin auction

KZ750 four cylinder was first introduced as a 1980 model, and the 750 twins were made from 76-80, and 82-83, there was no 81 model 750 twin.

It's eBay, so "Buyer Beware"

77KZ650 wrote:

If you swap to the 750 top end, you will need to swap cam sprockets with your 650. the early 650s use a roller chain, while the 750s use a hyvo. using the 650 "roller" sprockets on the 750 cams is how you make your crank work with the 750 stuff. and yes you will need to enlarge the holes in the case to fit the larger sleeves, its not hard.

Hey medic24.
77kz650 is correct on the swap as I just did this and it is pretty much a bolt on.

If you retain the 650 roller cam chain after swapping 650 sprockets onto the 750 cams, you should also keep the 650 cam chain adjuster that is mounted on the back of the cylinders under the carbs.

You might want to also look at the carb issue. If you are keeping the stock 650 carbs you may have to rejet the 650 carbs to compensate for the extra displacement. Of course, then you will want to bore the 750 to 810, mill, port and polish the 750 head etc....

Cheers-Colin Firth-Ontario Canada
1977 Kz 650 Custom with 14,000 miles. Wiseco 810, WG Mikuni 28's and lottsa go-fast goodies.

OK... I realize I will have to enlarge the case, so.... switching the cam chain sprockets, and maybe a carb issue.... should do it then? AND... Thank you all for the input!
Dave

Sorry... should I just drop in an entire KZ750 engine?
If so, any expected "issues"?
Dave

There really arent many issues to putting the 750 in. The biggest is the charging system, you can either use the 650s generator or the 750s alternator. I used the alternator on mine. If you get enough parts with the 750 you will also get Kawasakis stock electronic ignition (unless you already have an aftermarket)

I used the 650s Mikuni VM24 carbs and they were fine for me. I was never out there racing, but the bike moved me around good enough

del

dan what year is the engine, and how much are you asking for it?