Petcock Starting Procedures

[ghostrider]

All,

  Can someone direct me to the proper start up procedure for using the Petcock?  The bikes we used at the safety course all had automatic fuel cutoff valves and as such, I didnt get to practice using a Petcock.

  Please let me know if you have any questions.

Thank you,

Mike

[Jimustanguitar]

The fuel valve on Yamaha's from this era are vacuum operated, so you shouldn't need to mess with it for the most part. It will turn itself on and off automatically.

There are 3 positions:

ON - I think that's what it's called :) Is for everyday use. It will turn on and off with vacuum from the engine if it works properly.

PRI - For prime. This setting will flow all the time without vacuum. If you drained your carbs, or are having trouble starting the bike and you think it's due to lack of fuel or vacuum, you can turn it to this setting and know that you're flowing fuel.

RES - Reserve, for when you're running out of gas on the normal setting, and need a few more miles to get to the station. This setting is also vacuum operated.

[don_vanecek]

And I'm sure you all know that "reserve" is not some seperate tank somewhere, only that the petcock is now taking gas out of a lower part of the gas tank.   

[Jimustanguitar]

Nobody showed you the other gas cap to fill your reserve tank back up?

:)

[The Prophet of Doom]

Good responses guys.  I'd have just told him to read the manual.

[ghostrider]

Jimustanguitar - very much appreciate your feedback.  You clearly explained how the valve is to be used and I am very appreciative. 

don_vanecek - thank you for the clarification on the reserve setting and tank. 

ProphetOfDoom - thanks for the negative attitude.  Very happy to hear that new riders and their questions aren't welcome in your eyes.

[QBS]

Ghost...highly recommend that any time you're starting your bike after it has set for more than two days, you put the petcock in the "pri" position and wait a minute or so to give the float bowls time to fill.  After the bike has started, move the petcock to the "run" position.  This helps save wear and tear on your battery and starter motor.

If the petcock is left in the "Pri" position and the bike is ridden, the reserve function is defeated and you'll get no warning of impending fuel shortage.  Also, if left in the "pri" position with the bike not running, you'll be exposing yourself to the vagaries of potentially leaking float needle valves.  This could lead to draining your gas tank onto the floor of your garage or, worse, filling your engine crankcase with gasoline if your float bowl overflow drains lines are blocked.  I haven't trusted my float bowl needle valves in many years.  Long ago, I installed in line fuel cut off valves to and from my '83's petcock.  This gives me a complete defense against both leaky float valves....And....internally leaking petcocks.  Both were problems I've discovered and defeated during 29 years of ownership.

A related tid bit: Fuel flow in the "pri" position with less than approx. a half gallon of fuel in the tank is problematic.  It has been my experience that it doesn't happen.  This means that the float bowl filling procedure outlined above is ineffective.  This can lead to difficult starting after the bike has been sitting for a week or more.  The fix is to always have at least a half a tank of gas on board when starting from those conditions.

[ghostrider]

QBS - thank you for the tips on the Prime setting.  I will be picking the bike up from the shop in a couple of days.  Rather than fiddle around with the petcock there, I want to be mentally prepared to start it up and ride off.

[The Prophet of Doom]

ProphetOfDoom - thanks for the negative attitude.  Very happy to hear that new riders and their questions aren't welcome in your eyes.

Yamaha put a lot of effort in producing the owners and workshop manuals so that you can be familiar with basic operations of the motorcycle.  If you don't read them, then you will be missing all the handy life saving tips that you might not know to ask.

You will find if you go through my posts that I'm more than welcoming to new riders.

[iain]

hey prophet
maybe ghost is illiterate and cant read the manual, he could be from one of the southern states..

Iain
NZ

[Re-Vision]

He lives near the city of "Brotherly Love" in Pennsylvania. Southern Americans read as well as anyone else Iain. Ghostrider, everyone here can assure you that the Kiwi's support newcomers as well as any national group here and this is what makes this a good site for Vision owners from all over the world. Your retorts might be better appreciated if you wait until you know the folks here a little better. Reading the manuals and researching your problems make for better discussions and prevents wasted effort on well-documented subjects that have already been thrashed over and we are all glad that you are here.     BDC

[QBS]

iain, is that your best thinking?

[iain]

Boys, you gotta love the kiwi's

Iain
NZ

[Rick G]

Not everyone has , or has access to an owners manual or shop manual . Hence the reason for the ROV forum!

[The Prophet of Doom]

Not everyone has , or has access to an owners manual or shop manual . Hence the reason for the ROV forum!

and the reason for sharing resources
Haynes is still available in bookstores, though probably out of print now.
Links to genuine Yamaha documents and others can be found here http://ridersofvision.net/rovforum/index.php?topic=12221.0