Guest smittypig24 Posted July 26, 2013 Share Posted July 26, 2013 Quick backstory...I got this bike running, rode it for about 100 miles. Smelled like it was running rich. Would occasionally backfire. When parked in the garage, it was slowly leaking gas. The petcock was leaking a little so I fixed it, figured it fixed the problem. I go to start it up and a ton of gas shoots out the exhaust. Took the carbs off, opened them up, everything looked normal. Put it back together and it did it again! What is going on? Is the engine sucking too much fuel through it with every stroke? My old fuel injected bike had a fuel pressure regulator, but this one doesn't right? Do you think my fuel pump is messed up? What's going on here? Help!!!!!!!!!! Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted July 26, 2013 Share Posted July 26, 2013 maybe the floats. im not too big into carbs. im sure someone will have some good advice soon though. Link to comment Share on other sites More sharing options...
Guest Posted July 26, 2013 Share Posted July 26, 2013 No...it's not the floats. The gas is going through the engine and out the exhaust. I just don't know why it's dumping fuel in there. Maybe the fuel pump is pumping too much? Or maybe the fuel pump also acts as a regulator and it's letting too much gas through? I'm stumping. I'm hoping someone will have insight soon as it's going to be a nice weekend!!! Link to comment Share on other sites More sharing options...
Member Contributer mk2davis Posted July 26, 2013 Member Contributer Share Posted July 26, 2013 I haven't had this problem before, but hopefully we can still think of something. How long have you had your bike for? I'm thinking there are only two primary circuits that could allow that much fuel to run through your motor. Either your main jets are hugely oversized, or your choke is on without your knowledge. I'd pull the plugs, and see if the situation is in all cylinders, or just one. My first thought was that a jet had fallen out, allowing your bike to ingest a huge amount of fuel. This seems unlikely since you said everything looked fine when you opened them up. Try operating your choke with the tank and air box off. Does that seem to operate correctly? If so, I'd take a look at your jets in the offending cylinders. I would not think it's your fuel pump, as it only puts out 2 to 3 pounds of pressure. Much lower than a FI bike. The float bowls act as your regulator. But as you already stated, I'd expect big puddles of gas when the bike is not operating if it were your bowls. I'm sure you would have mentioned it, but are all your cylinders firing? A bad coil would allow a cylinder to cycle through unburnt gas. If nothing is obvious, you can try running a gravity feed, bypassing your fuel pump. Others have done this without issue. If your condition persists, you'd know the fuel pump is not the culprit, I'm sure someone else will chime in if I'm off base on this, but this is what I would look at. Link to comment Share on other sites More sharing options...
Member Contributer Cogswell Posted July 26, 2013 Member Contributer Share Posted July 26, 2013 You didn't describe how you ruled out the floats being the problem. For carbs the floats are the fuel regulation system - there is no FPR on these as in an FI system. Floats can require close inspection to spot issues. Two things can go wrong - either the float(s) develop a leak and fill with fuel, or if they're not made from metal the material degrades - either way they sink in the bowl allowing fuel through un-abated. Another problem that can develop as carbs age is that the small rubber tip on the needles that are attached to the floats that plug the inlet orifice degrade or develop a groove in them and no longer seal adequately. And sometimes the tiniest piece of trash, or varnish from old fuel in the system can hang up the needle or prevent it from sealing properly. If you didn't mention the leaking I would also suspect a severely plugged air filter for running rich, but the leaking seems to be the culprit. My $.02 would be to get the carbs on a bench, carefully check that the floats are working properly (actually float and don't sink), inspect the needles and make sure everything is spotlessly clean. And whatever you do, leave all 4 assembled as a unit - do not break them apart no matter how tempting that might be. It will be a royal PITA to get them all back together working properly in unison. Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted July 26, 2013 Member Contributer Share Posted July 26, 2013 Remove the carbs, check the float valves & valve seats & floats heights for damage, dirt, or level. You can do a manual pressure test. Remove the fuel supply hose to the carbs & ensure that there is NO crud in the hose or the fuel galleries. One of those things is your problem if its happening whilst stopped. Check your engine oil as if fuel has been running through the open valves of a cylinder, then it will also have passed the rings in that cylinder & contaminated the oil, that can destroy your engine ! Link to comment Share on other sites More sharing options...
Member Contributer gll429 Posted July 26, 2013 Member Contributer Share Posted July 26, 2013 simply put.. its your carbs... either the float , float needle , junk in the carb.. OR one of the plugs ISNT firing.. Link to comment Share on other sites More sharing options...
BRad704 Posted July 26, 2013 Share Posted July 26, 2013 simply put.. its your carbs... either the float , float needle , junk in the carb.. OR one of the plugs ISNT firing.. This was my first though as well. Fuel "pouring" from the exhaust sounds like one or more of the plugs is either toasted or an elec problem is preventing them from getting spark. Link to comment Share on other sites More sharing options...
Guest Posted July 26, 2013 Share Posted July 26, 2013 It was a decent amount of gas coming out. It shot out like a geyser! I would think it would have to be all 4 cylinders not getting spark as none of them were firing...probably a good thing because if all that gas in the exhaust would have ignited...wow, that would have been quite a show! The plugs only have about 150 miles on them and it ran fine last time I parked it. I already had 2 stuck float needles which prevented gas from getting in the carbs. Fixed that and the floats seem to work fine. If the floats are bad, wouldn't that mean that the gas would just pour out the overflow tubes, and not dump more fuel into the engine? The jets are limiting how much gas can get through right? (all jets are stock and clean...i can see through them) Is there anyone out there who knows these bikes inside and out that wants to make a new friend and give me their phone number? :) Link to comment Share on other sites More sharing options...
Member Contributer V-FORE Posted July 26, 2013 Member Contributer Share Posted July 26, 2013 another thing to check is the float needles they are rubber and do go bad, I replaced mine when I noticed fuel smell in the oil and figured it was running way to rich. Replaced the little needles and all was better. So the Floats may be fine but if the needle is not seating properly it does no good Link to comment Share on other sites More sharing options...
Member Contributer YoshiHNS Posted July 26, 2013 Member Contributer Share Posted July 26, 2013 Does your bike run at all? Have you pulled your plugs and looked at them to tell if they are covered in fuel? Have you checked that your plugs are getting spark? Have you checked your oil for gas in it? Are you 100% sure that's fuel coming out of the exhaust and not condensation? Are your jets actually clean with no debris on the walls, or can you just see light through them? Did you check your float heights? Did you check that your overflow lines are clear and can flow fuel? Link to comment Share on other sites More sharing options...
Member Contributer Mohawk Posted July 28, 2013 Member Contributer Share Posted July 28, 2013 This was my first though as well. Fuel "pouring" from the exhaust sounds like one or more of the plugs is either toasted or an elec problem is preventing them from getting spark. A missing spark will not produce liquid fuel in an exhaust ! Think what goes into a cylinder is vapour & then if it exits in a multi cylinder then the next exhaust opening will ignite the vapour in the headers ! Link to comment Share on other sites More sharing options...
Member Contributer gmtech94 Posted July 28, 2013 Member Contributer Share Posted July 28, 2013 Does this bike have a vacuum operated petcock so it only runs fuel when the engine is running ,you said that the petcock had a problem it may be possible that it is sucking fuel through the vacuum line directly into the cylinders . That would give you large amounts of fuel in the exhaust . Link to comment Share on other sites More sharing options...
Member Contributer gll429 Posted July 28, 2013 Member Contributer Share Posted July 28, 2013 This was my first though as well. Fuel "pouring" from the exhaust sounds like one or more of the plugs is either toasted or an elec problem is preventing them from getting spark. A missing spark will not produce liquid fuel in an exhaust ! Think what goes into a cylinder is vapour & then if it exits in a multi cylinder then the next exhaust opening will ignite the vapour in the headers ! tell that to the people who have had it happen to their bike. it SHOULDNT.. but on some bikes the vapor condenses and pools at the bottom of the pipe.. and when THAT ignites. even I CAN hear it! Link to comment Share on other sites More sharing options...
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