You correct it is not a 1978 B1 it is a B2. Unfortunately I have a 1977 KZ650 service manual, I thought it was a 1978 manual, the B1 in the manual that look like mine. Now I know why the petcock in this manual is not the same as I used to have on the bike.
Actually, based upon the serial number from my old registration it is a 1978 B2 made in Japan
EngineID KZ650BE076568
SerialNum: KZ650B037186
According to the following link
KZ650 Engine and frame numbershttps://kzrider.com/forum/5-chassis/536286-kz650-frame-and-engine-number-confusions
It was originally blue, but I got took the bike apart and got the frame and the bike painted red (flame). See that attached pictures
As per the attached picture it is a vacuum carb.
The petcock part number I found is 51023-1023, but I couldn't find one.
First step is to replace the oil, MacGyver a fake gas tank, use a boost for battery, just see if I can get the engine running before I spend too much money on it.
Questions:
I got my serial number off my old registration - where is the actual serial number? (I couldn't find it).
Anyone provide any tips on MacGyver'ing a pseudo tank ...? ...
My brake master cylinder likely need to be replaced as well - anyone know what other bike makes/models that would have a master cylinder I could use as a replacement? The existing is in bad shape, and I've never rebuilt one before.
Still would need a replacement petcock is all goes well - I did measure it, center-to-center is 40mm