petcock positions for 1978 KZ400

Hi Guys....

i was working on that KZ400 (1978) a little today (picked it up from a friend... needs LOTS of work!)...

anyway, the petcock has three positions:

On
Res
Pri

when i turned it to "Pri" gas started flowing out a bottom tube...

?

is that right?

i took the oppurtunity to drain the tank (which i wanted to do anyway)....

does this type of petcock have an

OFF position?

thanks...
- prime

Yes, it is right. What you have is a vacuum operated petcock. The prime position will always flow fuel.

The ON position only flows when there is a vacuum from a running engine, the RES position acts the same.

Use PRI to fill the carb bowls, then switch to ON. Don't leave it on PRI if the bike isn't running.

thanks!

so, there is then no way to take off tank unless it is emptied???

or would the "on" position (or "res") be ok (i.e., no vacuum, no flow?)...

Use the on position

thanks....

just sounds SO WRONG to use "on" for "off"!

but i do understand whay....

- prime