Base Gasket Replacement

Hello Fellow KZ Friends,
I am going to be tearing down my 1977 KZ 650 B1 to repair a leaking base gasket. I am going to be ordering my gaskets and O-rings from Z1. The top end kit has the two 92055-111(oval) in the kit and I am also getting the two 92055-101 (10mm) and two 92055-099 (8.8mm) and the one I need for the tachometer drive. I see in my one manuals that there are four large what I am going to call O-rings that look like they go around the bottom of the cylinders to the top of the block…what are these…will I need to get them and if so what are the part numbers? I also would like to know if there is anything else I am missing. I want to order everything all at once so I can do this whole thing at one time so it will have the least impact on riding time. Just getting into good riding season and I can’t stand to be down waiting to order parts that I missed or forgot.

Excellent question about the o-rings! They are a mystery part that was included in all the original KZ650-B1 and KZ650-C1 parts diagrams and then (here's the mystery part) they disappeared from later parts diagrams. They are part number 92055-089 - O-ring 67mm (see parts diagram below). I guess later bikes didn't have them, but here's my suggestion - buy 4 of them and if your engine has them replace them with the 4 new ones. (At least that's my plan if I ever rebuild mine, so I now have 4 in my parts bin.) Here's a place that has them in New Old Stock for $1 each (see link). Ed

www.nwvintagecycleparts.com/search-resul...arch.x=7&search.y=12

Thanks Ed...I could not find out what they were. Great help. Thanks.

I now have these O-rings. I test fitted them last night and I and not sure what the O-rings are supposed to seal. If I slide the O-rings over the cylinders and let them rest on the surface; there is an interference with the base gasket and O-rings. There seems to be a groove that the O-rings can fit into between the sleeves and the aluminum but it is going to be a very tight fit. If they do fit into this groove…what are they sealing, because after they are in the groove they are below the sealing surface?

They don't do anything, I always leave them out.