petcock question - or anyone have an exploded diagram?

[bwiencek]

OK - reading the forums and trying to figure out what's up with my fuel petcock - in reading there is some "little tab" that's easy to get messed up - anyone have a diagram with this "tab" shown? Also - what are the symptoms if someone screws this up? I'm thinking the previous owner screwed it up and I may be suffering the symptoms....

[paradoxmd]

What are the symptoms?

[bwiencek]

What are the symptoms?

1) Fuel set to "PRI" it only runs out slowly - would probably take a couple hours to run out of fuel at the rate it was going.

2) engine seem to starve for fuel when taking off, when at higher RPM's, doesn't want to "pull" below 5K RPM

3) when riding and shifting real slow (i.e. light throttle, then close throttle while pulling clutch, granny shifft, let out clutch) for a second or so it's got good power and pulls then falls flat and stutters.

That's about the symptoms as I know them right now - on the "to do" list is to pull the plugs, check their condition and replace.

[md86]

Re: petcock question - or anyone have an exploded diagram?

OK - reading the forums and trying to figure out what's up with my fuel petcock - in reading there is some "little tab" that's easy to get messed up - anyone have a diagram with this "tab" shown?

I'd bet the little tab is the spring-type deal inside . It sits under the round plastic thing , and if you twist on it wrong it'll be FUBAR . The knob has a ramp , and as the ramp goes up the metal tab , the tab gets pushed into the diaphram , opening it so fuel flows . If you mess that up , it'll either cause it to ALWAYS be on prime , or prime will never work again , depending on HOW you mess it up .

[bwiencek]

Re: petcock question - or anyone have an exploded diagram?

I'd bet the little tab is the spring-type deal inside . It sits under the round plastic thing , and if you twist on it wrong it'll be FUBAR . The knob has a ramp , and as the ramp goes up the metal tab , the tab gets pushed into the diaphram , opening it so fuel flows . If you mess that up , it'll either cause it to ALWAYS be on prime , or prime will never work again , depending on HOW you mess it up .

So - does it ONLY change the "prime" function so that it won't work well but the other functions it has no bearing on? (i.e. on and res) - I'm thinking that spring/tab might be screwed up a bit as it really trickes real slow - probably would take at least 30-45 seconds to even fill the float bowls... Guess I might have to get the vacuum pump out and test the fuel flow of the petcock on "ON"

[md86]

I'm fairly sure that's what the little spring deal does .

[atrent]

petcock question

I am having problems with my gs400 petcock that sound very similar. A diagram would be a very useful thing. I can't figure out how the brss spring type affair allows furl to flow in the prime position.
alex

[Kreylyn]

http://katriders.com/vb/showthread.php?t=96553 has lots of pics...

Turn the selector knob, that turns the pastic piece inside with a ramp. As the ramp pushes against the spring, that tip of the spread pushes against the diaphram. When the diaprham is open, fuel flows.

Res and On requires a vacuum to open the diaphram.

If you have a partial blockage inside... then all 3 positions would flow slowly.

Krey

[1990gsx 600]

well hers another thing it could be a vacuum leak. or if its like mine the diphram is shot. if fuel flows while the vacuum line isnt attached than your diphram is at fault and if thats the case than you may have to clean the carbs. because of the litlle peices of the diaphram getting in them. that is if you dont have in line filters. but either way a carb clean is always a good thing to do.