Is this a fuel petcock issue or just a coincidence?

[Jedison]

Hey all, my 92 600 Kat runs good, then dies, and even the throttle won't kick in. Now I'm thinking these are spark plugs (they've never been changed, just waiting for them to arrive in the mail), or even possibly related back to the air filter (once again waiting for a replacement in the mail). Problem is right now I can't really take the fairings off as much of the bolts are missing and I doubt they will go back on unless I have the proper bolts (bolt kit also in the mail). So whatever I can live with that, buuuuuut.....

I've noticed as soon as I turn my fuel petcock (teehee) to the 3 oclock or prime position the bike will start up again, and I've been leaving it like that and the bike runs ok (no fluid leaking out...so far), now when I leave it in the ON position the bike seems to sputter out (not backfire), I'm not sure if this is just a coincidence or what, but I'm wondering if it could be petcock related? I'm also wondering if maybe work was done to it and the wiring is messed inside it (positions don't match the stock).

So would this be petcock related? Or does that not sound like it has anything to do with it? I have a strong hunch it's my spark plugs but I still think it may be the petcock...it's also worth noting my gas mileage isn't the greatest on my Katana (half tank for less than 100km), so that also puts me back to the petcock worry...grrrr... Thanks guys!

[Kreylyn]

My first thought... is the petcock does not have the vacuum line hooked up to it so it's not working.

Could also be the petcock needs to have a rebuild kit installed. You would need to test it to know which, meaning... hooking a vacuum line up on it and checking if it works with/without vacuum in the differnt settings.

click the wiki link above, and search 'petcock" for more info on how it works.

If there is a vacuum line, and it's not plugged onto the petcock, that could cause a vacuum leak issue with carb 4 and that would = running issues.

Krey

[Jedison]

My first thought... is the petcock does not have the vacuum line hooked up to it so it's not working.

Could also be the petcock needs to have a rebuild kit installed. You would need to test it to know which, meaning... hooking a vacuum line up on it and checking if it works with/without vacuum in the differnt settings.

click the wiki link above, and search 'petcock" for more info on how it works.

If there is a vacuum line, and it's not plugged onto the petcock, that could cause a vacuum leak issue with carb 4 and that would = running issues.

Krey

Hmm I'll maybe crack it open anyways. Is a rebuild kit a big undertaking? Also looking on it now, I don't the vacuum line is hooked up, there's a rubber hose unhooked sticking out the side which I've tucked in to the fender, which I assumed was a fuel siphon (I blew on it and it sounded like air around the fuel tank), looking back in my utter noobness with petcocks (teehee), I'd almost guaruntee that's what it is...good call thanks.

If that's not the case, and I need a vacuum line to test with, where do you get a vacuum line, an automotive parts store? Also what should I be looking for in terms of how the vacuum line reacts? Thanks again man, I'm almost positive that's what that hose is from...I don't know why I assumed motorcycles just have siphon hoses just sticking out of them...god...

[Kreylyn]

You should read these links for more info and understanding on how and what the parts are.

http://katriders.com/wiki/index.php5?title=Petcock

http://katriders.com/wiki/index.php5?title=Hose_Connections

http://katriders.com/wiki/index.php5?title=Image:Carbs101.pdf

If you take off the seat, remove the 2 bolts on the tank under it... you can then lift the tank off. You may need to pull the left fairing out a bit to get the petcock out, but generally lifting the right side first will get you clearance to pull it out.

You should then be able to clearly see everything listed in the link above for the hose connections.

Krey

[Badfaerie]

Stupid question, how much gas do you have in the tank? Have you tried it on reserve?

[Jedison]

Stupid question, how much gas do you have in the tank? Have you tried it on reserve?

I thought about that but, I had over a half tank when it did what it did. I'll try it on reserve to maybe the suction will be better? But I'm thinking that hose is disconnected so it won't matter probably?

Also thanks for the link, that image makes the hose connections look surprisingly less complicated than I thought, I was afraid I'd rip it open and all hell would break loose...

[Badfaerie]

I thought about that but, I had over a half tank when it did what it did. I'll try it on reserve to maybe the suction will be better? But I'm thinking that hose is disconnected so it won't matter probably?

Also thanks for the link, that image makes the hose connections look surprisingly less complicated than I thought, I was afraid I'd rip it open and all hell would break loose...

The pick up for reserve is lower than the main pickup so if you are low on gas it'll run on reserve. But Tim's right, sounds like you don't have the vacuum line hooked up. That line is what opens the petcock when it's running, without that you get no gas.

[Jedison]

The pick up for reserve is lower than the main pickup so if you are low on gas it'll run on reserve. But Tim's right, sounds like you don't have the vacuum line hooked up. That line is what opens the petcock when it's running, without that you get no gas.

Time to go home and reattach the "siphoning" hose...

[Mojoe]

I'll try it on reserve to maybe the suction will be better? But I'm thinking that hose is disconnected so it won't matter probably?

whether on reserve or on, it does not effect the vacuum. like Badfaerie stated, it is only to switch over to the other pickup. "reserve" is just what it sounds like....it keeps a small amount of gas aside for when you start running out with it in the "on" position.

[Badfaerie]

Time to go home and reattach the "siphoning" hose...

It's not exactly a siphoning hose, or even at all.

Here's how it works. There's a spring and a diaphragm in the petcock. Then there's vacuum applied to the hose in the back with it turned to "on" or "reserve", it compresses that spring and diaphram and opens up a passage for the fuel to flow through. There is no force, or pumping or anything, it's all gravity feed. When you turn it to prime, it bypasses that spring and diaphragm and just lets the fuel flow freely. This allows you to fill the bowls of the carbs to have enough gas to start the engine as there's no vacuum until the engine is running.

So, the hoses on the sides, one coming out towards the front of the bike, and the one coming out towards the back of the bike are fuel out lines. The one in the back of the petcock, that comes out towards the right side, or across the bike, is the vacuum like that opens the petcock.

[Jedison]

Haha I was joking about the siphoning hose.

As it turns out, whoever did the carbs before totally connected the hoses wrong. The prime setting went to one of the fuel drainage valves (there's two by the looks of it) so that's why my gas was going down, and one of the carb air vent hoses wasn't even hooked up so I did that. So it was the petcock, but more so just a mixture of everything being totally messed up.

Quick question too, do the carb air vent hoses connect to anything other than the carburator? I'm assuming they just run air away from the bike but I wanted to be sure. Bike starts up and runs way nicer now. Thanks again guys.

[Kreylyn]

Haha I was joking about the siphoning hose.

As it turns out, whoever did the carbs before totally connected the hoses wrong. The prime setting went to one of the fuel drainage valves (there's two by the looks of it) so that's why my gas was going down, and one of the carb air vent hoses wasn't even hooked up so I did that. So it was the petcock, but more so just a mixture of everything being totally messed up.

Quick question too, do the carb air vent hoses connect to anything other than the carburator? I'm assuming they just run air away from the bike but I wanted to be sure. Bike starts up and runs way nicer now. Thanks again guys.

Vent lines do not connect to anything on the other end. If the carbs end up turned over, fuel will drain out the vents. The lines help keep that from happening onto a hot engine if the bike goes down.

krey

[Jedison]

Well took her out tonight to go to some places and she was running great now. Adjusted the idle so she runs great too. That petcock (teehee) was definitely the problem. Thanks again guys!

Just need new spark plugs and for my foam air filter to arrive and I'm in business!!!