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Discussion Starter #1 (Edited)
Background: I brought the bike in the beginning of summer. It started pouring gas out of the overflow tube attached to carb. No. 39 in pic below. Don't mind the horriblely drawn arrow..Bike would start stalling out. Had to keep the throttle on all the time to keep her running. As you lose half the gas in your tank out the tube...Pulled seat off to verify where the gas was coming from. Had a friend change out parts that are numbered 20, 21, 19 and 26. Still had the same issue after running great for a day or two. Then she'd start back up with the leaking. If you start her up, shut her down for a few times she'd stop leaking, but would start up leaking again the next time you started it up. Well, that didn't work right. So I took the carb off, brought it down to a very reputable carb shop in town. He deals with nothing but carbs. I trust him as he has done numerous carbs in his life and knows what he's doing. He cleaned the carb up, soaking it in whatever he uses overnight. He replaced parts number1, 4,5,3,6,7,10,8 and 9. He inspected all the other parts and said the jets where fine, they weren't plugged up and that the parts I had replaced earlier where installed correctly and working fine. He set everything back to spec, the floats where not set at the correct hieght, which I knew because we did set the float low to see if it would still flood out. The floats where working properly, not sticking or anything and they floated like they where supposed to. There wasn't any debris in the carb causing the float or needle to stick.

Get carb put back on the bike. Take her for an hour spin, she runs great. Better than she ever has. Get home, turn her off. Go back the next day, start her up, she's leaking again out of the same tube. Now I'm at a loss. The only other thing I can think of is the petcock being bad. This on has the prime on res switch. There's no off. I leave her in the on position. I do believe it is the stock petcock. I've had people tell me to change that out for a Yamaha Raptor petcock. But how do I tell which one will fit my bike? Dummy here when it comes to this. It's the only other thing I think it could be. All I know is I'm getting tired of taking the carb out.....
 

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Ghost in the machine
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It's only my opinion but wether the petcock is good or bad, fuel should not leak from the overflow tube unless part#19 (float needle and seat) fails to seal. This is normally caused by a leaking or mis-adjusted float, or dirt/cracks in the needle/seat.
 

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I agree with jag13 - float issues. You can check the float level with a clear tube on the bowl drain, turned up alongside the carb. The level should be 7mm below the bowl seating surface; there is a notch in the carb body showing this reference. I'd guess there may be something in the space above the float valve that sticks in it, or the float itself has fuel inside. You can check the latter by removing the float and shaking it.
 

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I don't know about micunis but on some carbs htere is a little known vacuum diaphragm that increases gas flow when the engine revs. because these are vacuume driven main jets, you might have an obstruction on one of them, or one of your needles may be bent or not sealing properly. Even a pro can miss the secondary vac. If it is stuck, it allows a trickle of gas that might be considered overflow. I fixed one of these on an old dodge dump truck once.

remember that most of the micunis are gravity fed, and it's vacuum that sucks them into the carb. I have never heard of a carb overflow tube, so make sure your tubing is hooked up right.
Another thing... check your oil for gas in it.
 

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Discussion Starter #7
I don't know about micunis but on some carbs htere is a little known vacuum diaphragm that increases gas flow when the engine revs. because these are vacuume driven main jets, you might have an obstruction on one of them, or one of your needles may be bent or not sealing properly. Even a pro can miss the secondary vac. If it is stuck, it allows a trickle of gas that might be considered overflow. I fixed one of these on an old dodge dump truck once.

remember that most of the micunis are gravity fed, and it's vacuum that sucks them into the carb. I have never heard of a carb overflow tube, so make sure your tubing is hooked up right.
Another thing... check your oil for gas in it.
The proper name for it is the bowl vent hose.....I guess I just call it the overflow tube, cause that's what it's doing to me....My carb has two of them. They have never hooked up to anything....I tore the bike apart myself this afternoon and cannot find any logical place for them to connect to. I thought I was onto something, thinking there had to be a hose attached to the air cleaner, but that tube was already connected....drats......Both needles where changed. the one in the bowl and the other one. The only thing Kurt did not dig into would be the diaphram, but at 150 just for that part, not something one really wants to fix. He said there is a work around and that is installing the Yamaha Raptor petcock. Instead of having prime/on/res I would now have on/off/res. I would just have to make sure I turn the switch to off...Which is a more common petcock anyways. The person who owned the bike previously to me, always set the petcock on prime thinking this was the off position.

I correctly diagnosed a coil problem on a Blazer today when all the other guys where saying it was the fuel pump, but when it comes to fixing my own damned bike, I'm stumped.... I was right about the coil, truck started right up and I saved them 250 bucks. But boy, did I get dirty looks being a girl and having the right answer....
 

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Discussion Starter #8
I agree with jag13 - float issues. You can check the float level with a clear tube on the bowl drain, turned up alongside the carb. The level should be 7mm below the bowl seating surface; there is a notch in the carb body showing this reference. I'd guess there may be something in the space above the float valve that sticks in it, or the float itself has fuel inside. You can check the latter by removing the float and shaking it.

Kurt verifed the float level was correct by using this method. Float does float. There's no fuel in it. This is what has me puzzled. Both needles have been replaced as well as the seat and gasket. Gas doesn't leak out of the bowl, but the bowl vents. And to me a vent is just something that lets air in or out...
 

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Discussion Starter #9
I'm tempted to take the carb off my S40 and putting it on the Savage, it's basically the same dratting carb. But I don't want to hurt the one carb that is working, then I'd really be crying.
 

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Gas should never leak out of the bowl; the seal would be damaged for that to occur. The vent is also the overflow, and fuel should only flow from it if the bowl is over-filling. Something is causing your float valve to stick open, the question is, what? You may have to remove the bowl and test the valve. Check to see that the float can't shift and cause the valve pin to bind, and that the fuel flow really stops with the float lifted.
 

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Jag is correct... gas will not flow if the floats are working properly. Take them out and set them in a cup of gasoline to see if they'll float or sink.

If they float, then it's a mechanism problem. If they sink..well, there's yer problem.

~~~~~~~~~~~~~

Rather than replacing the petcock, install an inline fuel filter with a shut off valve. It's cheaper, faster, fine filters the fuel and a clear one will let you see the gas.
 

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Discussion Starter #12
The floats do float in a cup of gas. I've already tried that trick too. The only thing I could think of, is may be a bur or a depression of some sort that is causing the float to get stuck sometimes. It's just weird that it doesn't leak every time, but enough to make it unrideable. The inline fuel filter is on the repair list. I didn't know they had shut off valves. I'll make sure I get me one of those....

It's just hard to believe its still in the carb. The mechanic I brought it to deals with just carbs, and he is really really good. I place no blame on him though. Hes done numerous carbs for the family. Never once had any problems. If I can get the bike down there, he is going to take a look at her and he's pissed the carb is still not working right. It's got to be something so freaking simple we are going to have a duh moment when we find it.
 

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Oh, Oh! Just thought of something...does your petcock have a hose that leads directly to a vacuum intake on one of the carbs?

If so, that vacuum line is a shut off mechanism...even if the petcock is in the run position, fuel will not flow until the engine starts. There's a spring mech in the petcock and the vacuum pulls that spring back and allows fuel to flow. If that mech is leaking, it will allow fuel to flow into that vacuum port...that's another way gas can leak out that overflow tube.

The filter and the valve are separate items; but both easy to find.



 

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Discussion Starter #14
That's why I think its the petcock, this particular model (as well as my s40) has known issues with the petcock. It was only 25 dollars for the Yahmaha Raptor petcock, versus the stock petcock at 89. I've got You Tube instructions on how to modify to fit this petcock. I've also ordered a Clymers manual. Got the filter and shutoff valve ordered, as soon as everything comes in (which ain't gonna be till sept 8, boo hoo) we will give this a shot.
 

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When the bike is going to be sitting for a while, pull the vacuum hose off at the carb and put it in a glass jar; see if you end up with gas in the jar...shouldn't...if so, the petcock is having a problem...you can take them apart...maybe it just needs cleaned.

When in the prime position, gas should flow in that vacuum hose...and that's the only time...that's what "Prime" is all about...dumping gas directly into the carb and bypassing the float system.
 

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gas line return vac

You may have the gas line where the vacuum goes, and the vac line where the gas line goes, get a manual and make sure....

Also, there is also this thing with having all the washers and seals in order when they go on... even if they are in there, they have to be in the right order... pros usually don't miss this one!!!

another thing is that the carb itself was mis manufactured, this would mean that there was a flaw in the making, and that even if it tested OK that is would still fail... boo hoo!

usually when gas leaks everywhere, there is a problem with the delivery system, and from your drawing, you have the gas hooked up to the vac and the vac hooked up to the gas. don't know... thats what it looks like to me.
 

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Discussion Starter #17 (Edited)
You may have the gas line where the vacuum goes, and the vac line where the gas line goes, get a manual and make sure....

Also, there is also this thing with having all the washers and seals in order when they go on... even if they are in there, they have to be in the right order... pros usually don't miss this one!!!

another thing is that the carb itself was mis manufactured, this would mean that there was a flaw in the making, and that even if it tested OK that is would still fail... boo hoo!

usually when gas leaks everywhere, there is a problem with the delivery system, and from your drawing, you have the gas hooked up to the vac and the vac hooked up to the gas. don't know... thats what it looks like to me.
I'm done messing with it till the Clymers manual gets here. I guess it's possible that the lines got mixed up. I usually color code my computer wires, I'll have to color code these once I know I have them right. Stranger things have happened right? It's such a nice bike, I fell in love with it the first time I saw her. Love the handle bars on her.
 

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You may have the gas line where the vacuum goes, and the vac line where the gas line goes, get a manual and make sure....

Also, there is also this thing with having all the washers and seals in order when they go on... even if they are in there, they have to be in the right order... pros usually don't miss this one!!!

another thing is that the carb itself was mis manufactured, this would mean that there was a flaw in the making, and that even if it tested OK that is would still fail... boo hoo!

usually when gas leaks everywhere, there is a problem with the delivery system, and from your drawing, you have the gas hooked up to the vac and the vac hooked up to the gas. don't know... thats what it looks like to me.
Wow! I never though about that. That would be about the only thing the carb builder wouldn't have control of. But then how would it run for so long before showing signs it isn't right? Wouldn't being reversed show it's ugly head almost instantly? Just seems like it would. But certainly a possible but I'm more familiar with cars and there the lines are usually a different size so that mistake is unlikely.
 

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Discussion Starter #19
Nope. They aren't mixed up. Dingbat me should have looked at the S40 ( my new bike) which has the same setup. Both of those lines are connected the same way. (so much for it being that easy). But there's two other lines ( the bowl vents) that are just kind of hanging loose on the savage. On the S40 they go up under the gas tank. I can't tell where they connect to or if they connect to anything, as I'm a bit afraid of messing with the S40 for fear of messing it up. I can find pics of the Carb, pics of the gas tank, petcock, but I can't find no pics of what lines connect to what. I'm hoping my manual will be in soon, hopefully that will give me some insight. If anyone knows whether these two lines are supposed to connect to something let me know. I've got two lines that go to the petcock. And these two mystery lines.
 
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