leaking gas out of exhaust pipe on 83' 650 NH while running

[no$4bike]

hello all! I am having a problem with gas leaking out of a very small crack on the left hand side of the exhaust pipe by the shifter while the bike is running. I just picked up this bike a week ago and have never ridden it yet. It starts great and seems to run really good so far on the center stand. but i noticed fuel blowing out of the bottem of the exhaust pipe. I shut the bike off and turned the fuel off also. Would this indicate there is a problem with carb #1? float? or could this be something more serious?

[BManz]

It could actually be running down from somewhere on your carbs or even the petcock.  Check for any residue.  Start with the simple troubleshooting first, hopefully just a carb float bowl gasket issue...

[no$4bike]

it is definately coming from the exhaust pipe because when it is running, it is blowing out of the crack. I just checked the oil and i can smell gas in the oil.

[muttstang]

are you sure it isn't just water that smells a bit like gas?  water is one of the byproducts of internal combustion engines.  and it is very common to see water dribbling out of an exhaust pipe.

[ariwhiteboy]

Sounds like rings are shot...what's running out of the pipes is most likely an oil/gas mix.  Since the rings are bad then gas is slipping down into the oil then makin it's way out of the exhaust valves.  This is not a problem you want to ride any amount of time with since the mixed fuel and oil can cause detonation in the crank case. 


Disclaimer: The above is a worst case scenario and I would try to make sure it couldn't be anything else (IE, leak, water vapor, etc.)

[no$4bike]

it is and oily gas mix. And one more thing i noticed. The right pipe seems to have gotten pretty hot, it has a blueish tint on the chrome right below the rear foot peg. the othere pipe appears to look normal.

[ariwhiteboy]

Well you're most likely going take er' apart and replace the rings.  Just out of curiosity, did your bike sit for a while and then you got it running again?  That's an almost sure fire way for the rings to go bad, rings sit in a non running motor, weaken and crack, then break apart when you run it again.  Just part of having an older vehicle.

[BManz]

If the petcock has a hole in the diaphragm would it not exhibit this behavior?  The gas would drain into the #2 cylinder because of the vacuum fitting.  Anyone else?

[coffee_brake]

Now it could be as simple as a float adjusted wrong, too, and that would allow excess fuel to go past the old rings. It's gotta go somewhere after all.

If the rings were in terrible shape it would certainly be smoking some, right?

Um...no$4bike...(dude what's your name?  )....are you running with the choke on all the time? I know you just got the bike, what do you know about it?
Is the bike smoking at all? A little puff when you first start it is not a big hairy deal, we're talking a lot of smoke. Lots of smoke even after the bike is warm would indicate needing new rings or new valve seats. Not a major operation or even an extremely expensive one, but you don't want to do it willy-nilly on your first bike.

When I've had enough fuel to come through the exhaust drain holes, in my case it's always been because of carb troubles causing it to run too rich or too lean.
Has the previous owner (PO) told you about recent carb work? Has the bike sat up unused for long periods of time? Miles? Anything else of note?

BTW if you smell a significant amount of fuel in the oil, you need to drop that oil because it's doing some bad stuff to your motor. If you're sure there's gas in the oil, change it right away.


Hey,  

[no$4bike]

i really dont know what the PO did to the bike or how long it sat. When i went to look at it, it fired right up and it did smoke, not horrible, but it did smoke. Nothing that concerned me much because the bike seemed to run really nice, so i bought it $400 ( the bike is in really good shape). But after reading some of these posts on here about the petcock, i went out and looked at mine and i noticed the PO put some sort of epoxy around it,so im assuming it must have leaked and that was his fix. Also, like i said earlier, the right pipe seems to have gotten a lot hotter than the left ( the fuel leaking pipe) because of the blueish tint on the chrome.

And by the way, My name is pronounced NO CASH FOR BIKE (no$4bike) because my hobbies burn up all my money!

[ariwhiteboy]

Hmmm  on pipe blued and the other not? Sounds like at one point it wasn't firing on all cylinders...also are you getting a bluish white smoke from the pipes?  That would indicate it was burning oil.

[no$4bike]

Hmmm  on pipe blued and the other not? Sounds like at one point it wasn't firing on all cylinders...also are you getting a bluish white smoke from the pipes?  That would indicate it was burning oil.

the pipes where like this when i bought it. yeah, i would say it white-ish smoke.

[ariwhiteboy]

Well I would almost bet my last dime the rings are shot, better bust out the manual and replace them.  (Don't worry I'm sure you will be able to do it)

[BManz]

Yea, sounds like you may have multiple small issues.  Test the petcock with a hand vacuum pump used for bleeding brakes and such.  Then go from there, maybe you don't have a good spark or a carb float problem on some cylinders.

[no$4bike]

i just removed the carbs and placed them upside down and removed the bowls and noticed that the float in carb number 1 is laying totally flat. meaning that,  when i touch the float, there is no little spring back, indicating to me that the needle is bad. The other carbs seem good. I switched the float and needle to on #1 and #2 and the origanal #1 still has no spring back and but #2 does spring back. So wouldnt this cause a bad seal and allow too much fuel in the carb?

[ariwhiteboy]

It could, like I said before though, start simple and cheap and work your way to expensive and difficult.

[BManz]

It could, like I said before though, start simple and cheap and work your way to expensive and difficult.

Well I would almost bet my last dime the rings are shot, better bust out the manual and replace them.  (Don't worry I'm sure you will be able to do it)

I am new, I am not trying to be a jerk here, ariwhiteboy when did you mention simple and cheap?
I think coffee_brake sums it up nicely below:

It could actually be running down from somewhere on your carbs or even the petcock.  Check for any residue.  Start with the simple troubleshooting first, hopefully just a carb float bowl gasket issue...
BManz

Now it could be as simple as a float adjusted wrong, too, and that would allow excess fuel to go past the old rings. It's gotta go somewhere after all.

If the rings were in terrible shape it would certainly be smoking some, right?

Um...no$4bike...(dude what's your name?  )....are you running with the choke on all the time? I know you just got the bike, what do you know about it?
Is the bike smoking at all? A little puff when you first start it is not a big hairy deal, we're talking a lot of smoke. Lots of smoke even after the bike is warm would indicate needing new rings or new valve seats. Not a major operation or even an extremely expensive one, but you don't want to do it willy-nilly on your first bike.

When I've had enough fuel to come through the exhaust drain holes, in my case it's always been because of carb troubles causing it to run too rich or too lean.
Has the previous owner (PO) told you about recent carb work? Has the bike sat up unused for long periods of time? Miles? Anything else of note?

BTW if you smell a significant amount of fuel in the oil, you need to drop that oil because it's doing some bad stuff to your motor. If you're sure there's gas in the oil, change it right away.
Hey,  

[coffee_brake]

Yeah the carbs are already out at this point. You need a manual for the bike first of all. If the floats needles are bad then yes, that will cause the fuel to flow too much (or too little, depending).
The petcock: does gas leak from the carbs when the bike is not running and the petcock is on?
Does the bike rev up easily?
Does it run with the choke off?
Does it idle smoothly without having to blip the throttle?

The answers to these questions can help a lot to narrow down your problem.

Adjusting floats is a real PIA so don't touch those float tangs till you know they need it.
It seems you have 1 or 2 problems that you need to fix before you think about replacing rings, because doing the rings won't be any benefit at all until these two things are right first: carbs and petcock.
You need to check the float levels and, if you're running on choke or the bike won't idle or rev, clean the carbs.
If it truly fires on both sides, idles smoothly and revs fine, I don't think you need to do any more than check the carbs out real good, possibly pull the jets to see if they're stock. Bench-synch the carbs (search this forum for an excellent photo how-to) and re-set the idle screws according to the manual. Easy stuff, won't take two hours if you use good tools and are careful and if nobody before you did poor work.

Then, you need to see if that petcock is having issues. Bmanz's idea with the vacuum pump is the best one. BTW you'll want that same vacuum pump for the clutch and brake fluid, it's not too expensive at the auto parts store or Harbor Freight. If the carbs are right and the petcock is functioning, THEN look at the rings.

If you're smoking a bit, then they are likely due for replacement. But you can ride it all of this season and do rings over the winter. A little smoking isn't going to leave you on the roadside, but it indicates that you need to do some work eventually. The bike shops are going to quote you outrageous amounts for this job but you CAN do it at home with basic tools for a whole lot less.

Don't get confused at all these words, instead eliminate the possible causes of fuel in the pipes one at a time. Start with carbs and petcock, then move on to other things.
Your float needle sticking is a very good place to start.
Get the manual, and you have a great learning project on your hands. The 650 is a heckuva good bike and will be worth your careful work.

Remember, if the oil has fuel in it, replace it. Despite the money issues, you gotta have tools if you want a cheap older bike. It's still cheaper than a new bike payment, right? If you don't spend a little on things like a manual, a torque wrench, and a few basic quality tools (Craftsman is the bare minimum for quality and what I use, Harbor Freight for things like hammers and prybars), then you won't be able to keep this older bike running.

Keep us posted, we love this stuff!

[ariwhiteboy]

It could, like I said before though, start simple and cheap and work your way to expensive and difficult.

Well I would almost bet my last dime the rings are shot, better bust out the manual and replace them.  (Don't worry I'm sure you will be able to do it)

I am new, I am not trying to be a jerk here, ariwhiteboy when did you mention simple and cheap?
I think coffee_brake sums it up nicely below:

Bmanz you're not being a jerk, and as you both will find out Mrs. coffee's mechanical skills far exceed my own and I'm not the least bit ashamed of that.  As far as the starting simple and cheap and then working his way to expensive I didn't say it verbatim (I usually do since this is one of my mechanical mantras) but it's what I was getting at when I said this:

Disclaimer: The above is a worst case scenario and I would try to make sure it couldn't be anything else (IE, leak, water vapor, etc.)

I do admit though I tend to be the eternal pessimist....

[no$4bike]

Yeah the carbs are already out at this point. You need a manual for the bike first of all. If the floats needles are bad then yes, that will cause the fuel to flow too much (or too little, depending).
The petcock: does gas leak from the carbs when the bike is not running and the petcock is on?
Does the bike rev up easily?
Does it run with the choke off?
Does it idle smoothly without having to blip the throttle?

the carbs DO leak when not running and the petcock is left on.
The bike does rev up nicely and it idles nicely too without the choke on.
I ordered a manual a few days ago.
I am interested on rebuilding the petcock because the PO epoxyed the edges because it must have leaked. Any info on rebuilding the petcock would be great!

Thanks everyone!

[coffee_brake]

This is a good sign. Well not good but not rings. Not yet.

Your floats are sticking, or are not adjusted correctly, or the needles are worn and need replacing. Your manual will have a parts blowup and diagrams to help.
In the meantime you do need to put hands on the needles. CAREFULLY remove the floats and keep them safe, don't bend them at all. the needles normally hang from the floats, you need to take a good look at them. You probably need new ones. They don't cost very much usually, they don't have to be Honda. They can be KandL or other aftermarket brands, as long as they say they will fit your 650, I'd ask your dealership on this one.
Look at the dark pointy part. See where it touches the seat of the carb? You shouldn't. If you can see on the pointy dark part where it seats, then that means the needle is bad. If you can't tell at all where it touches, then it should be good.

New needles, and polish the seat inside the carb with some kind of chrome polish on a Q-tip. Might as well pull the jets and see what number is stamped on them, just to make sure you have stock jets (you do have stock exhaust, I assume?) and make sure they're clean. While you're in there you can blow out all the fuel and air passages with a can of carb cleaner if there's any gunk in the carbs (wear eye protection that stuff is no joke).
Then, you will have to assemble your carbs and check the float level. This is a PIA but your manual will tell you how to do it. It takes a while, so give yourself a half a day and a big clean area to work, and patience. You should have your manual by then.
In the meantime, you can do the rest of it and get started finding some new float needles, and read up on petcocks here. I can't help you there, sorry.

But think outside the box, if the petcock is bad and a rebuild isn't feasible, you can conceivably make up your own bracket to mount an aftermarket new one. I've done this with a Kawasaki project using scrap aluminum and a brand new Harley petcock, it works great.

One more thing: if you don't already have one, get yourself a fuel filter and install that in the fuel line. Use little hose clamps. It's cheap insurance for older bikes.

Hopefully your petcock is not damaged.....

[ExTex]

You may want to check on EBay for a used petcock.
EBay also lists repair kits for your petcock.
Honda probably sells new petcocks, but they are expensive, so I'd try A & B above first.

A good working petcock and 4 good float bowl needle valves & floats are a must for this bike.


Ride safely,