Javenmcd

Yep...that's my Venture. I've exhausted all my simple resources on it and gotten to the point where it just isn't fun any more. I'm OCD to a certain extent with my stuff and if it's not working correctly I will obsess about it and I've already lost more sleep than I'd like.. The folks here on the forum have been so awesome in trying to help me and I'd just as soon see it go to a home where someone will appreciate the effort, money and time I've invested in it. It's going to be a great bike for someone that is going to know exactly what to do with it....that just isn't me.

Hi Rick....I made sure the engine was level side to side and front to back...checked at idle and while not running.. I doubt I'll have any more updates for you...I gave up.

Well....here's my update. Re-did the seats, needles with genuine Yamaha parts, rechecked all the carb screws, jets, fittings etc. Re-re-re-re set the float levels and re-installed the carbs and......the exact same problem persists. I guess I'm missing something (duh!). I'm selling it. I don't have any faith that I'll ever eliminate the problem or any faith that I'll ever trust it. At this point I really don't care if I lose my behind in the deal (which I most certainly will)...I just want it gone. What a bummer that I've invested SO MUCH time and gotten SO MANY things working and right on the bike only to get my ass kicked by the carbs....someone will turn the right screw or adjust the right mixture and end up with a steal. This afternoon I'd have sold it on the spot for the going scrap rate (8 cents a pound I think)

Anyone ever try to do a wet float level set? While I'm waiting for parts I hooked up to the drain lines on each carb just for sh&ts and giggles. Measured the center on the vacuum slide covers and put a piece of clear line from the drain next to marks I'd made....measured down from that point 16mm per the service manual...the left 2 carbs were spot on but the right 2 were way low. Seems like this method is pretty brainless...the fuel level line on the tubing can't exceed the level in the bowl....but I've no idea why it would be so low on the right side or if the method is flawed. If the level is in fact too low then the needles would constantly let fuel by, correct? Guess that gives me something to grind my teeth about in bed at night while I wait for those parts....cheers everyone.....

Thanks Rick. I did replace the o ring and gasket you're asking about in all of the carbs. I felt pretty confident in the job I did as far as attention to detail and cleaning. I'm far from a certified mechanic but I'm not afraid to turn wrenches and have done my own stuff for a few decades (I'm not saying that because I think anyone insulted me or my ability). I didn't replace needles, nozzles etc as they didn't seem to be causing any problems. My original issue I believe was a stuck float in one of the carbs (ironically I wasn't having ANY issues until I added some Seafoam as a treat to the carbs and I think that dislodged something) so I pulled the carbs and figured all of them could use a good cleaning and light rebuild while I was already that far. Now they all seem to leak fuel by upon cool down to some degree. I paid very close attention to the detailed guidelines on the forum here and after many re-reads of the guidelines I still can't see what I would have missed or caused which is why I'm still thinking needles and seats aren't working right. I'm giving the whole process a rest for a week or so as I've ordered OE seats, needles, inlet screens and seat-plug o rings. I decided to do that after watching a Shane Conley youtube video comparing some aftermarket needles to OE stuff. After his demonstration he talked about how easy it is to chase your own tail around thinking of all the possibilities when it just boiled down to inferior aftermarket parts not fitting correctly....at least I should be able to eliminate the needle/seat if that doesn't fix the problem...and if it doesn't it'll probably still leak enough fuel that I can strike a match and throw it on the ground and blow up the Venture like in a Hollywood movie.....I'm so tired of working on it.

I'll try and field several questions here.....I did soak the plugs in 100% wintergreen oil. When i reinstalled them they were definitely snug...almost too snug. When I installed the new needles I reused the factory needle clip that straddles the float tang. I've installed clear vent lines so that I'm able to see exactly which vents are doing what. The problem seems to be the same with or without the airbox installed. Obviously I install it on test rides but I've been removing it for idle tests in the garage. Keep in mind that the only time I'm seeing a problem now is after the bike is good and hot and I shut it down. After 10-30 minutes the vents will trickle and leak a few spoonfuls per carb (not always all carbs, sometimes 2...sometimes 3) and stop. Once they've done that the pump cycles again and the bowls refill. The bike isn't flooding out the air bleed jets since I've removed all the emissions crap so it at least starts and runs again instead of choking on gas.

That's the one....we'll crap. Not sure where that leaves me now.

Well...here's your daily update. Pulled the carbs and re-re-reverified float levels. Pulled the jet block rubber plugs and gave them a wintergreen/alcohol refresh bath. Reinstalled everything and.....same results. As the bike sits from being warm, the carb vents leak fuel. Fuel pump cycles but it does start as I guess it's not being restricted by all the crap I've removed from the system (emissions stuff, tank vent) Here's my next theory so let me know your input please: As the bike sits and cools its obviously letting fuel in (and back out thru the vents). When the carbs are inverted and off the bike you can blow into the inlet and air doesn't get by but it MUST be allowing fuel by. The only thing I can figure is that the K&L needles and seats aren't compatible with the bike and I need genuine Yamaha stuff. Maybe the fuel is even getting in AROUND the seat. The seats did have an o ring but they weren't very hard to press into place. Yay I get to pull the carbs for a 5th time!!! Anyone have any thoughts here?

Some of the folks on the forum have certainly been kind in helping me with my "new" old Venture. I've been getting quite frustrated with the carb issues I've been having but then I remind myself that I picked it up for $1000 and rode it home 150 miles before I could start tearing into it. I've learned heaps and I think I've done a pretty damn fine job on it so far...just got to iron out those carbs...I'll get there. Anyway, here's where I've come from and where I've gotten to....not bad for a grand I'd say. ​

Although I'll probably be pulling the carbs again it's awesome that you guys are willing to contribute some possible causes and actions....I'll post an update just for those that are interested.

I didn't replace them....there were some that were looser than others but there weren't any that were what I'd consider really loose. Not sure how snug they should be.

UPDATE: I pulled off/disconnected all the CA emissions crap (charcoal canister removed, disconnected the canister line to the carb and left it venting to atmosphere, fuel tank vent valve removed, disconnected the vent lines that ran to the air vent control valve) and ran temporary clear carb vent lines. Took it for a short ride and warmed it up several times and it didn't flood itself!!!! I did notice that the temporary vent lines I'd run were a little long so they curled back up and collected some fuel in them. Do I still have a float level issue? I set them (inverted) at 1.125" last time I had them off. I did install aftermarket K&L needles and seats so I don't know if that will affect my levels or not.....but hey, I'm making progress.

Thanks for getting back to me Cowpuc! I hope your health (or your loved one's) is improving. Here are some other observations...my carb vents merge into a single line and head to that fuel pump looking thingy (which i've found is called the air vent control valve). That valve is in the service manual and it has some trouble shooting criteria which I hope to do in the next day or so. It is powered so I'm supposed to power it and see if it operates by allowing air to pass under powered/unpowered conditions. From that valve the vents head over to that black charcoal canister. The fuel tank vent also Ts into that line and is input into the charcoal canister. The other line in the canister heads directly to that left front carb. Now....every time I've started the bike from dead cold it runs great. Once it's good and warm and you shut it off it seems good to go on a restart for 10 or so minutes. After that when you try and start it, it acts flooded. Fuel pump cycles repeatedly. Observing the carbs from the top shows fuel coming out of those air bleed jets on the top. The carbs will start grumbling and burbling (audibly and visually) while the bike is sitting there for the next 30 minutes. You smell raw fuel and you can see fuel mist or fog in each of the carbs. I've pulled all 4 vent lines and none of them ever puke fuel at all. Once the bike cools down completely again, it fires right up and you start the whole process over again. One of the last times it flooded, the canister filled with fuel and puked all over the side of the bike. I pulled the line from the carb and blew some low pressure air into the canister and purged it out of the exposed nipple in the bottom. ARE YOU GUYS AS CONFUSED AS I AM???? I guess my next plan is: 1)test the air vent control valve, 2)remove the charcoal canister, plug the exposed carb nipple and run vents individually out the rear of the bike, 3)remove the fuel tank vent valve.....don't know if any of these will help but I don't really have any idea of what else to do. At this point I'm ready to shell out a few hundred buck for someone to sort it but none of the shops in town will touch it because of its, ahem, "maturity..." Any other ideas or suggestions continue to be appreciated....my son, wife and I are all champing at the bit to get out and ride this thing.

I replaced both the fuel filter and the inlet screens last week....no change. Tomorrow I'm going to remove the canister and also perform troubleshooting on the air valve near the vents...thanks for the research. Hope it fixes the issue or the Venture is going away I think. A month wasted on it so far.....

Thanks for the reply AZ! Not many others have chimed in....I fear I may have stumped some. I'm going to look at vent control valve as soon as I get a chance....stay tuned if you care.

Does anyone know if this problem was ever resolved? My Venture is exhibiting the same problems originally noted here....

That sounds like a possibility....anyone have any experience with this piece or how to eliminate the CA crap?

that image is definitely not the fuel pump...my pump is factory and near the left rear footrest. No one has been able to tell me exactly what that component is but others with an 86 have the same setup....as for the canister, I pulled the line from the carb and put a bit of pressurized air down the line into the canister and it spewed fuel out of the nipple in the bottom so I know it's not full of fuel...just had some in it. Does that make sense?

Carbs haven't been synched since rebuild...but it is doing the same sort of thing it did pre-carb removal. My plan is to synchronize once I eliminate the flooding issue.

So I ran the bike for a quite a while today....no flooding while running but the idle is hanging. I checked for vacuum leaks unsuccessfully while it was running because it was bored. Shut it off and waited about ten minutes. Pulled the airbox lid and sure enough all four carbs are burbling. Is the fuel boiling for some reason? All my heat shields etc seem to be in place. I turn on the ignition and the fuel pump cycles and the carbs start to dump fuel. I pulled the vacuum line that runs from the front carb to the canister and it's dripping fuel from the carb nipple. I checked the tank vent and it seems fine. I pulled all four carb vents and none of them are venting fuel. Ideas anyone? SIDE NOTE....I just ran it again (it started reluctantly) and pulled the vacuum line thats on the carb and it didn't seem to make a difference in the way it ran. Should there be a vacuum at that point from the carb or should the line have a vacuum on it pulling AT the carb? So confused....

Thanks Scott...from what I'm told that exposed nipple on the brass cylinder is not supposed to be connected to anything (based on what others have said about their bikes here). I don't know about a regulator but maybe one of the other guys reading this post does.....anyone?

The larger hose is connected directly to a large nipple on the bottom of the front carb (not the drain). The other carbs don't have this nipple. The other line Ts and runs and runs to 1) fuel tank vent and 2) the carb vents (which also T into the brass cylinder pictured in the 2nd image). Also worth noting when I've tried starting the bike when it was exhibiting the problem I've seen the nipple on on that brass cylinder actively SPEWING fuel onto the front cylinder bank (that's the front cylinder bank at the bottom of the 2nd image).

Here is the offending canister. There is an open nipple on the bottom that is dripping onto the frame rail. Here's some history. Bought the bike in early Winter. The carbs were about the only thing that weren't giving me problems. The engine ran great for a while. I decided to treat it to some Seafoam in the fuel. A few days later it didn't want to re-start after being warmed up. It became evident that it was flooding (at this point I didn't know if it was one or all the carbs) so as was mentioned on the forum, I figured it has dislodged something into one of the seats. It did flood badly enough to hydrolock once which scared the crap out of me. The crankcase level never seemed to change in the sightless so I didn't change the oil. Pulled the carbs and carefully went through them per AndyE's detailed write up. Replaced the needles and seats with K&L sets. Set float levels (according to specs found here) and reinstalled. Ran the bike and it flooded on all 4 carbs badly....spewing fuel up out of the air bleed jets...I figured that I had the float levels wrong somehow. Re-pulled the carbs yesterday and set the float levels lower (1.125" inverted) and re-installed. Ran bike static in the garage for 1/2 hour and re-started several times....no fuel pump cycling and no flooding! Yay, right? Nope. Ran the bike for a mile and started bogging badly. I thought maybe I'd fouled plugs so made a plan to change them when the bike cooled. Managed to get it home and shut it down....let it sit for several minutes and flipped the key. The pump still did not cycle and still no flooding! Yay, right? Nope. 1/2 hour later I went in the garage and theres a puddle under the bike. I didn't even get to witness what in the world the problem was but that canister has fuel on the bottom nipple. I pulled the line that goes from the top of the canister to bottom of the left front carb and its moist with fuel. Flip the key and the fuel pump cycles several times.....Hope that helps in some way and I do appreciate the help you guys are offering but I'm losing trust and faith in this thing fast....

Haven't checked the vent yet...I was just looking at some other pages and saw that! It would be awesome if it was that easy! Is the vent at the top of the tank?

Thanks for the input folks....here are a few other notes. The bike ran great until all 4 carbs started exhibiting the symptoms simultaneously which leads me to think that it's not related to a single carb. Strangely enough, I've pulled the vents and none of them ever overflowed....the main air jets on the intake sides of the carbs all spewed gas though. All 4 carb seats sealed and didn't leak by when I inverted them and blew into the fuel inlet pipes too.... Ugh....