My question is concerning the petcock(i think that is what it is called). When I put it in the "run" position no gas comes out. I'm curious, shouldn't the gas be coming out the bottom, or is a vacuum needed. I know this may seem like a stupid question, however I have taken apart the peacock and all looks good. The bike that is concerned here is 94 250 ninja. Thanks for any help. and laughs for this dumb question.

In reserve or run it doesn't let any gas out. I took the petcock apart, and I think I may know what is wrong with it. On the back of the petcock there is a gasket with a little spring pushing on a little plug. I think the gasket has lost it's flexablility, resulting in no gas able to pass through the petcock. That is the only thing I can think of, because I removed the filter on the end of the small pipes, and still no gas passes through.

My main question is: Is gas going to drip/flow out of the petcock when put in the run/reserve position. Noone has been able to answer this question.

 

dont worry its normal. My lol petcock lol sorry, has run prime and res. it only "leaks" in prime. Its normal.

 

So your saying it should leak in run. However mine is not leaking at all. Not a drop. That is with it in run for over an hour, and it is dry as a bone.

I got it working. I had to tweak the diaphragm, but it is working now.

 

I hyave a 85 ninja 600 and its normal when it doesnt leak in anythign but prime. It only leaks in prime.
Remember if it leaks out even during all 3 settings then you wont be able to take off your gas tank with out losing fuel

 

The vacuum operated petcock should NOT flow any fuel in 'on' or 'res' mode unless there IS vacuum. If the bike has a prime selection on the petcock, this bypasses the vacuum diaphragm, and allows fuel to flow without any vacuum.

 

What he said. Look at your petcock. There are 2 tubes coming off it. The larger one is the main feed to the bottom of the carbs, the smaller one hooks to one of the vacume inlet on the carbs, usually the #2. Start your bike in neutral. Take the vacuum hose and unhook it from the petcock or kink it. The motor will die once the bowls empty. You will then need to put the petcock on "prime" to start the bike.

They made the petcock a vacuum feed so you don't have to turn the gas off when you aren't riding. Some of us around here are old enough to remember having to turn the gas off on bikes. They would flood if you didn't. Gravity feed will do that.

On vacuum feed petcocks, the 0-rings inside will go bad and gas will seep around them.

 

hey i kinda have the same problem, could somebody show me a picture or diagram of where i am supposed to hook that second vaccum hose that goes from the smaller valve to wherever it goes on the carbs. that would be awesome!! thanks

Chris

 

I don't have a picture, but you will see one nipple on the top of every carb body. Some of them will be blocked of with a rubber cap, and at least one will be uncovered where the vacuum feed to the petcock line goes.