The International CBX Owners Association

Can anyone give me insight as to what is going on here? On startup fuel is pouring out the bottom between carbs 1 and 2. First thought was coming from between carbs, but then decided to remove tank..connect another fuel dispenser and leak is gone. This led me to believe the vacuum fuel tap is the culprit..or something wrong in the fuel line. Took tank to someone in the know and he says its not a vacuum fuel tap. Only change I did since carbs were cleaned is add an inline fuel filter (bike ran fine for 3weeks after this). My thinking is now remove filter and have new fuel hose direct..making sure its good and tight at the ends. Ive left the fuel dispenser on for now and will go for another start tomorrow and can almost guarantee there will be no leak.

Are all the carb overflow hoses connected at the manifold, is the plastic manifold broken or cracked? If any of the carb floats stick and overflow the gas leak can come from below the carbs at the hose manifold instead of out the overflow hose below the engine.

A stuck carb float needle can cause an intermittent leak.

Not to be 'doom and gloom' -- however, I'd guess that the fuel transfer connector tube between 1&2 is leaking due to old oring(s). Often, when this happens, the initial leak will stop after a short time -- 15 seconds to a couple minutes. This is due to the old slightly shrunken oring(s) doing a little swelling after soaking in a little fuel. Eventually, they won't be able to swell enough; and, to stop leaking. Then it's necessary to pull the carbs, separate them and install new orings on all the fuel connector tubes. A bit like the old Fram commercial: "You can pay me now; or, pay me later." I'll hope that your problem is something else simpler. Won't bet on it.

P.S. I nursed mine for two years before having to do the oring job.

mcferreira100 wrote:Can anyone give me insight as to what is going on here? On startup fuel is pouring out the bottom between carbs 1 and 2. First thought was coming from between carbs, but then decided to remove tank..connect another fuel dispenser and leak is gone. This led me to believe the vacuum fuel tap is the culprit..or something wrong in the fuel line. Took tank to someone in the know and he says its not a vacuum fuel tap. Only change I did since carbs were cleaned is add an inline fuel filter (bike ran fine for 3weeks after this). My thinking is now remove filter and have new fuel hose direct..making sure its good and tight at the ends. Ive left the fuel dispenser on for now and will go for another start tomorrow and can almost guarantee there will be no leak.

Your "someone in the know" obviously didn't know that the petcock on the tank is not a vacuum petcock (like some Kawasaki and Yamaha units), but the vacuum petcock on your bike - if you have one - sits on the carbs and is a separate unit from the one on the tank. Check the top of the carbs where the fuel line from the tank petcock connects to and see if you have a diaphragm valve unit there or if the line goes directly into the carbs.

Yes there is a unit sitting on top the carbs..fuel line goes from petcock to this unit. Is that not the fuel pump?

No fuel pump - these are carbs, not fuel injection. That is the vacuum valve on top of the carbs and rarely, if ever, leaks. I'd be looking where Larry said if you cannot find an obvious fuel line crack.

Dave

Is the in line fuel filter the type that has a clear section and screws together? I have one like that and when I turned the fuel on after ra winter lay up fuel pissed everywhere until I nipped it up a bit. As I put it away dry I guess the seals dried out a bit - it's been fuel tight since then..

Simon

This is the filter. Going put in a new fuel line and leave filter off. That's about all I can think of doing without carbs coming off again.

It's pretty easy to troubleshoot the suggestions above visually.

But while you have the vacuum shutoff bypassed and on an auxiliary bottle make darn sure you do not flood any of the cylinders with gas and try to start the bike or you will experience the dreaded hydrolock and possibly bend a rod or worse, pull all of your spark plugs before you spin the motor.

Tried to start the bike off the auxillary fuel line (its an XL125 tank which is somewhat dirty inside)and it just swung until battery almost flat..no sign of starting. It ran 2 days ago off auxillary tank. I'm thinking maybe this filter getting blocked and causing restriction. Charging battery now and will eliminate the filter tomorrow and go for start with original tank back on.

Also while bike is running..as soon as I close the fuel tap the leak stops. Also leads me to believe its in the fuel line.

So it started after sorting fuel line (almost set fire to it getting damn fuel line on..replacement pipe was bit too small). It ran showing no leaks..let it run warm for about 15mins. Will see what it does in the morning.

Why is it after running warm..switch off..then immediately go for another start..it battles to swing and wont start..like battery flat? (battery was charged yesterday)

Leaving it running for 15 minutes without a large fan blowing on the engine is not a good idea.
The engine gets too hot and also you could permanently discolour your exhaust.
Also the engine will idling is not revving high enough to charge your battery. That MIGHT be part of hard starting problem but i suspect heat is the main culprit.

mc,

Bad orings will do just what you have described. If they are marginal, they will swell enough after 5 minutes to 30 minutes of exposure to fuel. Mine would do this -- then be good for all year. That is, until I let the bike sit over Winter, here, here with the fuel valve closed. (5 months) That would be long enough for the orings to 'dry out'. This worked for 2 or 3 years/seasons. Then, it wouldn't stop leaking. (Between 1 & 2 carbs.) Bit the bullet - pulled the carbs and installed new viton orings. Good to go since. PIA. But, then, 'stuff' happens to all of us as we age. Ask me how I know.

Ok,,I think good news. Started again today..let run again about 15mins and no leaks..and took for short run round the block. So seems eliminating fuel filter might have sorted it. Really suspecting the battery though..even after charging it battles to swing the engine (charged again today). Starter has been done so any recommendation for a really good strong battery for this bike..Ive read on here the Goldwing battery can fit.