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I think they're all larger. A member sent me a roller for the clutch sprocket and it was too big. I ordered one from a bearing supply that came out of France. Good price and cured me of buying cheap CHINESE Caltric R/R's. Destroyed everything. 
The center pin is what they call the big pin. More teeth. 
Steve

Mikaw wrote:

Is the 25mm taper crank the one that is commonly referred to as “big pin” I’ve heard the term but never knew 100% sure what exactly what was being described 

Yes! The MK2/ST crank is known as the big pin crank and is the strongest stock roller chain crank..( all cranks after this are J type with HYVO camchains)..
As well as the extra tooth on the center sprocket they also have larger crank pins and larger needle roller bearings.
They still fit all the earlier crankcases as the outer races for the roller bearings remain the same diameter.
 

Injected wrote:

The 650/750 engine crank ends do not have a key, its really not an issue if you tighten the end bolt to FSM specs. The difference here is the starter clutch is bundled on that end. Kawasaki must have found that they could eliminate the key on later model cranks.

The early 22mm 900 cranks ( and 1st model 1000)  had an 8mm rotor bolt which couldn't be tightened enough to prevent the rotor from slipping without the presence of the key.
The later 1000 22mm cranks had the rotor bolt increased to 10mm which allowed enough torque to be applied to secure the rotor without a key.
keyed and non keyed rotors for the 22mm cranks are the same taper and dimensions and a keyed rotor can be used on a non keyed crank but not the other way round.
The MK2/ST cranks and beyond changed the alt rotor to the larger dished design so the diameter of the crank pins and taper were increased along with larger 12mm bolt etc.

The 650/750 engines have always used a 10mm rotor bolt starting back in 1977.

Thanks again to all for the help and great info. You guys really know your Kaws. Anyway the cam sprockets are 32 teeth so I'm quite certain it's a MK 2 crank. But after another look at the original starter assembly that I still have,  the three bolts that hold the starter clutch to the rotor are sheared off. I think they tried to use that assembly with the larger motor (1327cc) and crankshaft. and it failed. I was then given the option of an outboard starter, or to kick start it. Anyway hopefully a MK 2 starter assembly can be fitted. Also a pic of a heavy duty starter that Pogue Racing used to sell from there catalog back then, maybe there's some still around ??

urankjj wrote:

Anyway hopefully a MK 2 starter assembly can be fitted. Also a pic of a heavy duty starter that Pogue Racing used to sell from there catalog back then, maybe there's some still around ?? 

Yes!  You will need the MK2/ST starter clutch.
For the starter motor you either need the stronger four brush one from the later Z1000J/GPZ's or one of the HD ones that Ricks Motorsport sell.
 

The "super starter" in the add picture you posted was offered by Paul Cashio Engineering out of Belle Chasse Louisiana. The last I heard was that Paul passed away in 2021, and I don't know if anybody picked up that business.

He exclusively rewound starter motors for big CC drag bikes, he was all over the DragBike.com forums till they shut that down. Most guys spun the starters on 24V using two on board batteries.

Besides the 4 brush GPZ1100 or the Ricks you could also use the Honda CB900 0.8KW Mitsuba SM-220 starter. With the Honda starter you have to relocate the ground wire lead to get it to mount properly (not a big deal)

I see you have a big block so guessing its 1327cc, depending on the compression (street) you should be OK with the above options. A stock KZ1000 starter would be too weak but some of those other options may be OK if you ran lower compression using a thick base gasket or milling piston tops if it is a 13:1 kit. I suspect Pro Street engines running big CC's are probably running 10:1 or lower.





 

Thank you, thats more great information.  Yes it's a 1327. Wiseco street kit, 10.5:1, and I'll probably go with the "Ricks" starter once I get the starter clutch and rotor fitted.