Tech Help

Hello all,
I have a 1978 KZ650D (SR) and I am trying to get it back up and running. The cam chain broke on it and the head wasn't looking to great. I ended up getting a low mileage KZ750 head complete with cams. I am swapping the 650 cam sprockets onto the 750 cams so that I may use the 650 cam chain (since I already bought a new one) and also so my 650 valve cover will go on. I was told though that the 650 head gasket will not work with the 750 head on the 650 jugs? Can anyone confirm this and let me know which gasket to use. once i get the head situated the only thing I will need to get it going is piston rings, which I recently found out are incredibly hard to find and if you do they are outrageously expensive. Has anyone found a way around paying the $200+ dollars for oem rings? I know I just wrote a novel but any help on any of these things would be great. THANKS

Anyone?

Curious as to why at this stage a ring job is deemed necessary. And whether oversize rings are being considered along with boring the 650 block. Or whether stock size rings absent re-bore are being considered.

Does 650 head gasket look as if it would seal okay when mated against the 750 head?

Good Luck!

I just recently picked up the bike and it was not running and has been sitting for some years. The bike has 44,000 miles on it and the motor is out and taken apart right now so I figured new rings would be a good idea. I havnt really thought about using oversized rings, but any suggestions on what I should do would be great. The head hasnt arrived yet so I cant hold te gasket up to it at this time.

Might also be concerned about possible damage in lower end.

Lower end looks pretty good, gears look clean, crank spins freely, primary chain looks good. I think I got lucky on that. From what I saw when i took apart the motor it looks like the cam chain made a clean break and the chain skipped a tooth and got stuck against the side of the head and cam sprocket. It wasnt budging from that spot, so I think the previous guy thought the motor seized and just parked the bike. I am however still concerned about getting the top end and jugs put together correctly. so keep the good advice coming please

measure the bores to see how far out they are before buying rings incase it needs to be bored oversize

KafeZ650 wrote:

I will need to get it going is piston rings, which I recently found out are incredibly hard to find and if you do they are outrageously expensive. Has anyone found a way around paying the $200+ dollars for oem rings?

650 Rings actually do appear on eBay from time-to-time but not with any amount of regularity. I am pretty sure they are still available from Mother Kaw...if you do go OEM, then order them through www.z1Enterprises.com as you will get the best available deal and most likely cheaper than through a Kawasaki dealer.

Thank you for all the help everyone! z1 was the first place I checked with the rings but the didnt have them for my app. Also if I do go with the oversized rings won't i need oversized pistons? or will I be able to just run oversized rings on the standard pistons?