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Ba dum dum, ching...
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Discussion Starter #1
OK, it's been a couple of weeks until I could get back to my bike (both my father and step father have been in the hospital and except for working and taking time to take my MSF course I've been running between hospitals. (Of course they are in 2 different hospitals 60 miles apart.)

Now I decided to drain the tank and pull the petcock to check it but when I removed the fuel tube that runs from the petcock to the carb and opened the valve no fuel came out. I know there is fuel in the tank and I tried both the regular on and the reserve position so what's the deal?

Thx,
R
 

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Registered
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112 Posts
Hi Ron

This should be an easy one and with nothing to worry about, in the main tank position (lever straight down on my 1991 VN) it requires vacuum from the engine for the petrol to flow, in the "reserve" position the petrol should flow without the engine running.

There should be 3 pipes on the petcock:-

Front Carb
Rear Carb
Vacuum Line to front cylinder carb

Just make sure the lines go to the right spot.

Hope this helps.

Regards

DaveT
Kuala Lumpur
 

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Ba dum dum, ching...
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542 Posts
Discussion Starter #3
Thanks Dave. I'll try it in the reserve position.

R
 

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HAWK
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2,576 Posts
That depends on what year, the newer ones will not flow even in reserve.
IF it said prime then it might flow, if it said reserve then it will not flow without vacume.
Hope this helps
 

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Member
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What Chad said is true. There's a diaphragm w/ plunger inside the petcock that uses vacuum from the front carb to open. Put some kind of suction device on the vacuum line (I use the rubber ball from a siphoning hose, or if you have one of those "suck-the-snot-out-of-baby-noses-rubber-thingies") and it'll drain. Once it starts flowing, you can clamp the line to maintain the pressure as the tank empties.

Good luck.

P.S. Once you use the snot sucker on the bike, keep it in the garage and away from the kid's nose. :)
 

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Sparky!!!
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8,697 Posts
I love the fact that I have been a cage mechanic for so long and have so many cool toys for working on cages with. One tool in particular that helps with testing the petcock flow rate is a brake bleeder kit. The one I have has lots of little vacuum hoses, caps, and adapters...wich make it very easy to hook up to the vacuum port on the fuel tank, hook the other end of the tubing up to my suction gun and start pumping away, until fuel flows from the tank (usualy three good pumps does the trick.) Also I use the same tool to bleed my front brakes. I take a Zip Tie and tie down the front brake lever then hook up my hoses to the bleeder valves on the calipers....Both callapers at the same time since i have a t fitting as well....then just hook up the suction gun and start pumping away untill no more air is in the system...ususualy it takes me about 1 minute to bleed the brake lines from zero fluid in the system to completely bled w/ No Air pockets. Darn I just love my tools...lol...

Ohh and now you are saying dang I wish I had one of them neeto brake bleader kits....you can find them at Sears, Harbor Freight, and most auto parts stores. I got mine through Snap On, just because i used to get a huge school discount through them and it ended up being cheaper than the Sears one I was looking at.
 

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Ba dum dum, ching...
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542 Posts
Discussion Starter #7
Mine is a 2000 and the petcock says RES. As you said Slim, the fuel won't flow even on RES so I will need to pull vacuum on the line in order to empty the tank.
Thanks guys for the help,
R
 

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Ba dum dum, ching...
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542 Posts
Discussion Starter #8
Now what!?!

(And to think I begged my wife to let me get this thing...:doh:)

OK. Here's a new one. Tonight I was working on my bike (still) I had it running but really rough. At one point I turned it off to answer my phone and in trying to be a good MSF rider I turned off the fuel valve. When I went back to it for some reason I decided to try and start it with the fuel valve off. AND it started and ran GREAT!!! But, whenever I would try to turn the valve on it would start to sputter and stall. I could catch it and turn the valve back off and it would run great again. Open it and it would start to stall again. It got to the point that I began to wonder if I was operating the valve correctly but I checked and it was. I tried RES and it would sputter, back to OFF and it runs fine. What's the deal here am I on Bikers Candid Camera? :confused:

Thanks in advance for the answer that is forthcoming,
R
 

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Premium Member
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1,647 Posts
It sounds like you have a vacuum leak in the system. Either in the petcock or the line to it. I suspect the petcock itself. Try using the alternate vacuum source to open the petcock so fuel will flow. Plug the vacuum nipple on the carb and see how it runs with the petcock on Main or Res. If it runs ok, it's in the petcock and it may need to be either cleaned or rebuilt which is not hard.
 

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(And to think I begged my wife to let me get this thing...:doh:)

OK. Here's a new one. Tonight I was working on my bike (still) I had it running but really rough. At one point I turned it off to answer my phone and in trying to be a good MSF rider I turned off the fuel valve. When I went back to it for some reason I decided to try and start it with the fuel valve off. AND it started and ran GREAT!!! But, whenever I would try to turn the valve on it would start to sputter and stall. I could catch it and turn the valve back off and it would run great again. Open it and it would start to stall again. It got to the point that I began to wonder if I was operating the valve correctly but I checked and it was. I tried RES and it would sputter, back to OFF and it runs fine. What's the deal here am I on Bikers Candid Camera? :confused:

Thanks in advance for the answer that is forthcoming,
R
I would guess that your floats are too high or a sticking. When you turn the fuel on, the fuel coming down the pipe is forcing excess fuel into the bowls and flooding the engine. When you turn the petcock off, the bike is running on the fuel in the bowls without any extra being forced in.

But Like I said, just a guess
 

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Ba dum dum, ching...
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542 Posts
Discussion Starter #11
I would guess that your floats are too high or a sticking. When you turn the fuel on, the fuel coming down the pipe is forcing excess fuel into the bowls and flooding the engine. When you turn the petcock off, the bike is running on the fuel in the bowls without any extra being forced in.

But Like I said, just a guess
But how would I check that and if that's the case how do I fix it?
 

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Registered
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you could try rinning some seafoam thrugh them, sometimes tapping on the side of the bowl with a screwdriver handle will knock what ever it is loose. float level is checked with a clear piece of tubing connected to the drain and held up alongside the float bowl.
There are instructions in any of the books for these bikes.

Otherwise, Pull the carbs and clean them thoroughly
 

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Ba dum dum, ching...
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542 Posts
Discussion Starter #13
...Otherwise, Pull the carbs and clean them thoroughly
Yikes! :eek: Easy for you to say. I've never done that.

(Now where was that Clymers manual...)

R
 

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Premium Member
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There's a first time for everything!!!
 

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Ba dum dum, ching...
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542 Posts
Discussion Starter #15
Well, it's runnin...

Soooo, I'm working on the bike this afternoon and playing with the idle control and the fuel valve and all of a sudden it starts working. Running with the fuel valve open. Its seem to be running OK. I think perhaps it's running a little rich but none the less it's running and I'm on the road :motorcycl

Woo Hoo!
R
 
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