Front left carb not getting fuel, fuel coming out of vent hose.

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VmaxMann

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Four months out of country hunting wanted pedophile from LA, I go to start my Vmax, fires right up, but front left carb is dumping fuel from attached vent hose on left side of air box. Put stabilizer before leaving, fuel appears rusty. Tried pea shooter method on carb, no luck. What y'all think. Clogged jet? Haven't pulled apart yet. Sugared up ethanol? After adding stabilizer, I'm not sure I let it idle too long. Any help appreciated. Sean and Danny, any thoughts?
I did capture the pedophile in Bangkok.
 

Fire-medic

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Grit or a worn needle valve; the float, which controls the gas level in the float bowl, allows continuous flow of gas into the float bowl, and out the hose, because of a piece of grit between the rubber/viton tip of the needle valve, and the screw-in brass seat it sits-in; or wear of the needle valve. You also need to check the brass seat for the needle valve, to see if it's worn. You buy the seat and needle as a pair (part #36). I use either OEM carburetor parts, or I've also used K&L.

https://www.ebay.com/p/182601278?iid=313056771578 K&L carb kit $23.75 including shipping, for one carburetor

Might as-well check the float level while you're into the carbs. And, since you're in-there, first take a look in the gas tank, use a bright light, or a borescope (they have inexpensive accessories for your cellphone to make it one) to look everywhere you can in the gas tank. You're looking for bright, shiny metal everywhere. If you see dark sediments or rust, you're due for a tank removal and thorough cleaning and possibly the use of a tank liner product like POR-15 or similar. If you find that necessary, follow the directions exactly, or your results will be less-than satisfactory.

If you do find rust in the tank, don't say, "hell, I'm just gonna put it back together and run it, mebbe change-out the gas filter," because that's not going to fix it, and you're just in-for a boatload of frustration, chasing your tail, and poor operational performance. You've already found that to be the case, right? "Fuel appears rusty."

I would also pull the jet block, remove the pilot jet (part #42, to remove it calls-for a thin, long, narrow screwdriver blade) and the other jet in the jet block (part #44, called the main bleed pipe), and ensure both are clean and clear. A good carb soak and passageways blow-out to follow. Have on-hand four new jet block gaskets (part #35) because they usually tear removing the jet block. The carburetor bowl gasket, a thin, shaped O-ring usually does-not need replacement, unless it breaks. Removing the jet blocks requires you to split the carbs into front and rear pairs; you do-not need-to separate the carburetors into four separate pieces. Take lots of pics, to help you recall the relationship of parts to each-other, before and during your disassembly. Use a piece of cardboard, and punch holes into it for each fastener, use a fine-point Sharpie pen to label everything. A roll of narrow masking tape, to fasten parts like shaped pieces or linkages from the disassembly to the cardboard will help you to keep-track of everything, and ease your reassembly. The throttle springs and linkages do-not need to be disassembled other than to remove the tiny circlips on the rod holding the choke linkages together. Be very-careful when trying to remove these, as they like to suddenly fly-off the rod/linkage, and play 'hide & seek' with you. A pair of locking hemostats or forceps, or a good pair of needle-nose pliers with small tips will help you in removing these tiny circlips, and not-losing them.

Soaking the carbs will probably fill the four chambers which help in starting the bike, by providing enrichment of the fuel/air mix. Those four chambers have a brass piston and nut, with a rubber boot and gasket, referred-to as a 'starter set', part #20 in the fiche. Use a small open-end wrench to remove the brass nut which screws-into a small cast aluminum housing piece that holds the enrichment piston 'starter set' in-place. Take a look at the fiche for part #20, and the cast-aluminum housing that it goes-into, tell-me what is that part number for that small cast aluminum housing piece? Trick question: there is no part number for it on the fiche, as it is no-longer available! Be careful working with them! Use something like WD-40 to flush-out and to lubricate the 'starter set' piston and housing, insert the 'starter set' piston into the small cast aluminum housing piece, and snug-down the brass nut. This prevents you from having to disassemble the rockers and the shaft they are attached-to. The top of each of the 'starter set' brass pistons clip-onto the forked rockers, to activate the enrichment circuit for starting the bike. On the left side of the carbs, upon reassembly into a block of four, there is a bent-rod which connects the shafts for the starting enrichment circuit. Make sure that it's installed to look-like a frown. Consult the fiche if you have any-doubt about its positioning. Check that all-four 'starter set' brass pistons move together, and that they open fully, and close fully. The bent-rod can be bent to adjust the pistons' movement, as-needed to ensure full range-of-motion, and that they all close-completely. At the enrichment lever you can use enough torque on the screw to allow the "choke lever" to stay at whatever point you wish, don't over-tighten it.

If your bike is 20 years-old or more, I would consider replacing the molded-T rubber hose (part #65) which routes gas to the quartet of carburetors. These become brittle and hardened with age, especially if the bike has been stored outdoors or is in an area where there is a lot of ozone (smog) in the air, which causes rubber deterioration. It's not-uncommon when trying to manipulate a 20+ year-old rubber piece, that it cracks or tears. Having one on-hand before you tear-into the carbs is a good idea.

This sounds like a lot of b.s. to have to do, because of a ^$#!!* piddly-ass gas overflow hose peeing gas onto the ground, but if you have a gas water heater in the same place you store your motorcycle, you could end-up with a house fire. Gasoline vapors can travel 30 ft to a source of ignition like a natural gas water heater, or a gas furnace, and ignite. I'm a firefighter, I've seen it (now retired).

To get the bike running when it's back-together, you need some-sort of a carb synchronization tool. The analog gauge systems are cheapest, the electronic ones are most-expensive, the liquid ones cost-more than than the analog gauges. If you don't have one, even an inexpensive analog gauge set will get you the settings done which you need, and it will pay for itself the first time you use it.

What I'm telling you is that you can approach it from the viewpoint of, "I'm just gonna use a long socket extension, and tap on the leaking float bowl, and hope-that the piece of grit causing me all this grief is gonna dislodge itself, and come out the overflow tube. Then the ^%%$!* float needle valve will seal again!" It may, it may-not. Answer me this: where did that piece of grit come-from? A rusty, gunky tank? Then it's time to perform this maintenance.

One of the most-common things affecting our bikes is the pilot jets in the jet blocks becoming plugged with sediment or fine particulate material. You see in the one pic, where a pilot jet has a single strand of stainless steel wire sticking out of it. That single strand is a bit over 0.01" in diameter. It doesn't take much to plug those four pilot jets, and the ones on the left side seem to clog quicker, because most people use their side-stands, and the crud migrates to the lowest point, the left-side carburetors.

Yeah, I know, this is crazy, all's I wanna-do is stop the tiny hose from pissing-gasoline! Unfortunately, a leak in the wrong room with a gas-appliance could burn-down your bike storage area which just-may be your home/garage. Search-out what needs to be done, order the parts, and label those parts as you remove things.

https://www.ronayers.com/oemparts/a/yam/50045c0ef8700209bc7942f3/carburetor

One carb synch tool, I've used one similar to this for nearly 40 years:
https://www.amazon.com/WIN-MAX-Carburetor-Synchronizer-Adjustment-Tool/dp/B075YSWZ21/ref=sr_1_29?crid=3B1Q8EMWL35WB&dchild=1&keywords=motorcycle+carburetor+synchronization+tool&qid=1588561000&sprefix=motorcycle+carburetor+synchronization+,aps,177&sr=8-29 Amazon $47, free shipping

I also have a set of Motion Pro Carb Stix, there really isn't much-difference using either the Motion Pro Carb Stix or the analog gauges.

VMax carburetor.png VMax FloatLevel bowl off.jpg VMax pilot jet.jpg VMax pilot jet lighted.jpg
 
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dannymax

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Four months out of country hunting wanted pedophile from LA, I go to start my Vmax, fires right up, but front left carb is dumping fuel from attached vent hose on left side of air box. Put stabilizer before leaving, fuel appears rusty. Tried pea shooter method on carb, no luck. What y'all think. Clogged jet? Haven't pulled apart yet. Sugared up ethanol? After adding stabilizer, I'm not sure I let it idle too long. Any help appreciated. Sean and Danny, any thoughts?
I did capture the pedophile in Bangkok.
Congrats on a successful hunt!

Sounds like a stuck float or float needle. Maybe some tapping on that carb with a dead blow hammer, 2x4 end, or whatever is available?
 

Fire-medic

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Congrats on a successful hunt!

Sounds like a stuck float or float needle. Maybe some tapping on that carb with a dead blow hammer, 2x4 end, or whatever is available?
Yeah that's why I mentioned using a long socket extension, to tap on the float bowl. You can easily reach the float bowl and provide a bit of mass/momentum to it, a 1/2" X 12" socket extension makes a good weapon for this. I bet the time spent sitting didn't do the bike any favors. From his report on the rusty gas filter, I suspect a corroded gas tank. Quick & easy can be good for the short-term, but the underlying cause for that stuck-open carb float valve needs to be fixed.
 

VmaxMann

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I determined the fuel was just discolored from the fuel stabilizer. Inspection with bore light revealed clean tank. Tried a rubber mallet against the diaphragm last night, worked for few minutes ( fuel quit coming out of vent hose ), but shut it down to purge remaining fuel. Today after work, started right up and fuel again pumping out of vent hose. Extension and mallet next. I appreciate all the suggestions. Oh I did removed the cover to the affected carb, removed the needle and inspected for unusual wear, none observed. I believe the culprit is a stuck float. Fire-medic and Dannymax if your right, a $100 donation to Vmaxforum in both your names and a Cohiba for each of you for a post ride pleasure.
 

dannymax

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Sounds like the needle may be gummed up a little. If you can get it unstuck again maybe taking it for a good ride will flush it out. If not it may be time for a cleaning.
 

VmaxMann

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Sounds like the needle may be gummed up a little. If you can get it unstuck again maybe taking it for a good ride will flush it out. If not it may be time for a cleaning.
I removed the needle and it was clean. I tapped the fuel bowl with an extension and that resolved the " stuck float " issue. That was the problem. No more fuel out vent hose. Added fresh VP C14 fuel with some Seafoam and the bike sounds great. Well almost alright, a minor new idle problem has appeared, which I hope will disappear with a little road work. So, as I stated earlier, I will be making a donation in your and Fire-Medic's names. Also, where do I send your Cohiba. Thanks again Danny.
 

dannymax

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I removed the needle and it was clean. I tapped the fuel bowl with an extension and that resolved the " stuck float " issue. That was the problem. No more fuel out vent hose. Added fresh VP C14 fuel with some Seafoam and the bike sounds great. Well almost alright, a minor new idle problem has appeared, which I hope will disappear with a little road work. So, as I stated earlier, I will be making a donation in your and Fire-Medic's names. Also, where do I send your Cohiba. Thanks again Danny.
I meant the float needle...but sounds like you got it. The fresh fuel and a little Seafoam will hopefully flush it out.

Being as I had to Google Cohiba to find out what it was I guess I'm just not refined enough to enjoy one...how about you enjoy it for me! LOL
 
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