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Discussion Starter #1
I got a dumb question on a 1988 Shadow VT600:

For the fuel petcock, which position is on, off, and reserve?

The previous owner must have broke the lever, and he put a small hose clamp on it so it could be turned. I see the "ON", "OFF", "RES." on the valve, but since there is no indicator mark, I don't know where to position the valve. This is something I will fix soon.

The reason I ask is because I think the carbs are loading up overnight making it extremely hard to start. I wanted to shut the fuel off overnight to see if this is the culprit, but I can't tell which position is on or off.

Thanks
 

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rmccutchan said:
I got a dumb question on a 1988 Shadow VT600:
For the fuel petcock, which position is on, off, and reserve?
The previous owner must have broke the lever, and he put a small hose clamp on it so it could be turned. I see the "ON", "OFF", "RES." on the valve, but since there is no indicator mark, I don't know where to position the valve. This is something I will fix soon.
The reason I ask is because I think the carbs are loading up overnight making it extremely hard to start. I wanted to shut the fuel off overnight to see if this is the culprit, but I can't tell which position is on or off.
Thanks
Maybe the newer ones are different, but on my 750ACE the petcock knob only rotates 180 degrees. If you rotate it all the way to it's most counterclockwise position, it's "ON." If you rotate it all the way to it's most clockwise position it's "RES." And, in the middle is "OFF."
Phil
 

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Petcock

IF you believe that the carbs are over filling, the culprit is your float valves. The petcock does not determine the amount of fuel that are in the carbs.
 

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Phil said:
If you rotate it all the way to it's most counterclockwise position, it's "ON." If you rotate it all the way to it's most clockwise position it's "RES." And, in the middle is "OFF."
Phil
That's the way it is supposed to work.....and there originally was a little "arrow" painted on the bottom of the tank as an indicator of which position it is IN.

My experience, however, tells me that OFF is really hard to find; good luck with that.

I doubt that it will prove anything anyway. If the floats were WAY out of adjustment....or the needle valve leaking, you would have other indications overnight....like a puddle of gas on the floor. AND unless that model has a fuel pump, the vacume operated shut off will stop the gas flow anyway.

As for the hard starting part, how are you using the choke?
Does it sound like it is turning over as fast as it should ?
 

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Discussion Starter #6
I found the "off" position is exactly in the middle. I marked it with a sharpie. It does have a fuel pump.

I believe the carbs need some work. There was a puddle of gas on the floor after sitting overnight, and when I try to start it, a BUNCH of gas dumped out of the tail pipes. I even had a big flame shoot out of the tail pipe once. Scared the poo out of me! But my 14 year old son thought it was pretty cool.

I thought about putting some carb cleaner in the fuel to see if it would clean things. I suppose it couldn't hurt, but chances are it won't do much good.

I was hoping to limp it along without rebuilding the carbs, but my brother in law, who was a mechanic of 30 years and built his own custom chopper, said he will rebuild the carbs for me. He said that sometimes shutting the gas off while it is parked for a while will help.

After it is running, it does fine, though. All I have to do is bump the starter and it fires up good. It just doesn't like to start after sitting for a while.

Guess I should expect something like this for a 22 year old bike.
 

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I doubt that any kind of fuel cleaner is going to jelp you. Suggest you take the brother in law up on cleaning the carbs if you trust him. Probably a float problem, maybe just remove the bowls and check them and the floats out first.
Tim
 

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rmccutchan said:
I believe the carbs need some work. There was a puddle of gas on the floor after sitting overnight, and when I try to start it, a BUNCH of gas dumped out of the tail pipes.
This is NOT good. Trying to limp along without fixing the problem might cost you big time in the future. :shock:

Some of that gas that is leaking is, no doubt, ending up in the crankcase and diluting your oil.

You should NOT ride it until the problem is fixed.....and then the oil is changed. And, sure now that you found OFF, by all means, DO turn it off.
 

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rmccutchan said:
I found the "off" position is exactly in the middle. I marked it with a sharpie. It does have a fuel pump.

I was hoping to limp it along without rebuilding the carbs, but my brother in law, who was a mechanic of 30 years and built his own custom chopper, said he will rebuild the carbs for me. He said that sometimes shutting the gas off while it is parked for a while will help.

After it is running, it does fine, though. All I have to do is bump the starter and it fires up good. It just doesn't like to start after sitting for a while.

Guess I should expect something like this for a 22 year old bike.


the vacume operated petcocks have a rubber diapham that engine vacume pulls to one side of the chamber allowing fuel to flow.
The diapham can go bad and leak even with the petcock in off.
There should be an OEM repair package for it.
In the order of repairing/replacing things that should come first.
 

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Easy Rider 2 said:
Robt. said:
rmccutchan said:
It does have a fuel pump.
the vacume operated petcocks have a rubber diapham
Since he has a fuel pump, I don't think he has a vacume operated shut-off. :wink:
Actually you made me stop and think, so I did a little quick Homework and a 88 VT600 does not have a vac operated petcock.
But what do you think? Why is fuel flowing with the petcock in the off position? Should anyone here even suspect it could be bad and maybe mention that as a possibility? Before the carb is looked at?
Nobody here knows it all, that 750 in my sig, fuel pump and vac operated petcock....
 

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Robt. said:
But what do you think? Why is fuel flowing with the petcock in the off position? Should anyone here even suspect it could be bad and maybe mention that as a possibility?
I thought I DID mention that; maybe in a different thread.

MY manually operated petcock IS bad. I can turn it to OFF and ride all day. I even replaced it and it looks like the new one is going to do the same thing.
BUT.......
Even if that is the case, the float and needle valve in the carb should shut the fuel off when the bowl gets full. If it doesn't, the carb needs work; what the petcock is or is not doing has no bearing on that.
 

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Discussion Starter #13
The petcock is working properly. I had it to "off" overnight, and I still had a hard time starting it today. The bottom of the carbs were wet, but it didn't seem to flood when I started it. It acted like the carbs were empty and had to pump gas into them first (just guessing)

Anyway, I decided to let my brother-in-law take a look at it before I do any damage. I almost did it my self, but I would probably end up with a box of parts and STILL have to take it to him :)

It really sucks since it is supposed to be 73 tomorrow and I have the day off!!!!

Thanks for the posts. I wasn't thinking about getting gas into the crankcase.
 

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rmccutchan said:
The bottom of the carbs were wet, but it didn't seem to flood when I started it.
What? Yet you think the petcock "off" actually worked ??

I'm confused.......but at this point, it probably doesn't make any difference.

In the process of working on the carbs, you will likely find out for sure if the shut-off is really working or not.
 

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Captain D said:
I spose I got a faulty petcock, as my fuel won`t shut off either...
I can ride fer ever with the gas "off"...
I think a LOT of the Shadows are that way.
Most "normal" people would never think to try it though. :shock:

:wink:

I also found that when it stutters and I switch to reserve, it picks up and starts running again BEFORE I ever pass OFF in the rotation. This leads me to believe that if I accidentally had the knob about 15 degrees off (or roughly half way between RUN and OFF.....I would really be running on REserve and not know it).
 

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Discussion Starter #18
Easy Rider 2 said:
rmccutchan said:
The bottom of the carbs were wet, but it didn't seem to flood when I started it.
What? Yet you think the petcock "off" actually worked ??

I'm confused.......but at this point, it probably doesn't make any difference.

In the process of working on the carbs, you will likely find out for sure if the shut-off is really working or not.

I unhooked the gas line coming from the petcock and put it in a can, then turned the petcock to all positions, and the fuel stopped running at exactly the halfway point. I left it in that position for a while to make sure it wasn't leaking a little, and it did not leak.

I'm guessing the wet carburetors are due to whatever gas was in them at the time and leaked out overnight, thus leaving me with empty carburetors.

It seems to me that it is obviously the float valves. I have taken apart carburetors on small engines (briggs, etc.), and I know the float valves can be sensitive, and any little varnish from the gas can make them not work properly.

The bike runs great after I get it started, so I don't think there are going to be any issues other than the floats. (fingers crossed)

Thanks again.
 

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Discussion Starter #19
Thought I'd update in case someone else does a search with the same problem.

I had my brother-in-law work on the carbs. He said they were if fairly good shape, but he cleaned them anyway. He said he could not find anything that looked wrong, but he adjusted the floats a little just in case.

He found the "combination" to start it was to give it about 1/4 choke and just a little throttle, and now it fires right up like a new one, and no leaking.

Thanks for the posts.
 
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