Crankshaft Q

Aloha guys.

I was checking through Partzilla website and came across something I didn't know.

Going through their website, it seems as Kawasaki changed the crankshaft for KZ750 four some time in 83. Part # changed from 13031-1028 to 1314. Does anyone know what did they change? How can you tell the difference?

Reason why I'm asking is that I got a used crank from evilbay and want to find out if mine is old one or new. According to the seller, it came from 82 GPz, which should be from older part # 1028.

Anyone?

Many times the oems will change part numbers for something as simple as an updated heat treat process and it would not be something you can tell.

83 is when they changed to the hyvo cam chain so the gear on the crank changed.

The 750/4 bikes used the hyvo chain from the start.

Comparing the part numbers it seems the ignition side oil seal grew 3mm on the later crank. That would be a deal breaker unless you have the later crankcases.

The 1980 KZ750 uses the regular chain and not the hyvo ........ why you need that block for a 810 or 831cc kit for your 650.

KZB2 650 wrote: The 1980 KZ750 uses the regular chain and not the hyvo ........ why you need that block for a 810 or 831cc kit for your 650.

Incorrect. ALL 750/4's use the link plate hyvo type chain.

Nessism wrote: .............. ALL 750/4's use the link plate hyvo type chain.

Correct! If there's any doubt just look at pages 54 & 55 of the Kawasaki Service Manual provided by KZRider (link below). Ed

www.kzrider.com/modules/ServiceManuals/KZ750E1&H1.pdf

I stand corrected I was thinking they where like the KZ650's which changed in 81 not 83 like I posted.

No eBay APP ID and/or Cert ID defined in Kunena configurationAlso, there could be some confusion with the twins. They used roller chains, at least up to 1980 according to Kawasaki.
www.kawasaki.com/Parts/PartsDiagram/144037/1980/KZ750-G1

Here's one on ebay, clearly a roller chain (for the 750 twins).

Thanks guys. Oil seal, huh? I never had a thought to check that one!

As of now, things are working out OK. I have early case with early crank, so seals should be OK. I mean I have them installed on the case and don't seem to have any problem. 3mm will be rather large gap, so I should be able to tell.

Always remembered reading you needed a 1980 750 block to have the right cutouts for the reg chain set up used on the 77-78 KZ650s to go with the 810 cc kit so I always thought it used the reg chain too but was wrong. I see the # is 1054 for the 1980 block and 1062 for the 81-82 but the picture shows the cutouts being the same so maybe that info was wrong too.

KZB2 650 wrote: Always remembered reading you needed a 1980 750 block to have the right cutouts for the reg chain set up used on the 77-78 KZ650s to go with the 810 cc kit so I always thought it used the reg chain too but was wrong. I see the # is 1054 for the 1980 block and 1062 for the 81-82 but the picture shows the cutouts being the same so maybe that info was wrong too.

I don't think it's "only" the 1980 cylinder that had the cutouts, at least some 1981 and maybe even later engines had them too. If you think that's confusing try studying head gasket part numbers some time. In theory the 650 and at least some 750's share the same gasket, but you won't find a clear supercession chain anywhere.