Stupid question about petcock

OK, I have a 1980 550 ltd. My stupid question is.... which setting is which for the petcock? There are no markings for on, off, etc.

Feel free to laugh at the total newbie, but I also appreciate any help.


ps- manual is on the way via ebay, but the guy turns out to be gone till Dec 8, so shipping isn't for a while yet, and patience is not one of my virtues.

:woohoo: :woohoo: :woohoo: :woohoo: :woohoo: hell i dont know,but you said to laugh!:laugh: welcome to z-jungle !

it has a vacuam operated petcock so the position to the back is the prime position[fuel will flow freely]

There should be PRI (prime), ON (on:huh: ) and RES (reserve). prime is to fill the bowls on the carbs (occasional use). ON is the position it will mostly be in. RES is for when you run out of gas on ON (it should get thee to a gas station). When not running it should be on ON also.

The following procedure is best done out of doors with NO SMOKING and no lights or open flames nearby when performing this check. Make sure you're wearing the usual personal protective gear when handling gasoline in ANY circumstance. Having a suitable fire extinguisher close to hand is also an excellent idea.
If you yourself have never performed this type of procedure before, I strongly recommend that you have this work performed by a licenced motorcycle mechanic.
Are all the ambulance-chasers happy now ???:laugh:

With most vacuum operated petcocks (and I would assume yours is no different) the normal "Run" position is with the lever handle pointing straight down. "Reserve" is usually with the lever handle pointing toward the front of the bike. "Prime" is usually with the lever handle pointing towards the rear of the bike. A quick check can be made by disconnecting the gas line from the petcock outlet and WITH THE ENGINE STOPPED AND KEY TURNED OFF, rotate the petcock lever to the various positions. Fuel should NOT flow out of the petcock in any position except the "Prime" position. Have a small cup handy to catch any flow of gas in any case.

Do you have the Owner's Manual? -->> pull-down compartment under seat

Per FSM for 77-79KZ1000's, vac petcock positions are

ON - - - lever handle down (run)

RES - - - lever handle up (reserve)

PRI - - - lever hande to rear (prime)

Sorry don't know whether 80KZ550LTD positions might differ.

When testing for fuel flow in the ON or RES position, a vacuum (suction) must be supplied to the petcock.

When testing for fuel flow in the PRI position, no vacuum is required.

Good Luck!

Thanks for the answers, much appreciated!