Oh boy, smoke/gas coming out of valve cover breather hose

[sark]

I just got back from a ride and noticed smoke coming out from under the seat of my g450. I got down along side the bike and observed very much white smoke and a some FUEL coming out of the breather hose from the valve cover. The hose was not connected to the airbox. Also, the bike felt hotter then it should be, so i checked the oil to find that the crankcase was almost bone dry. I have exactly 79 miles on the bike since the last oil change and I didn't observe any leaks. The bike seemed to be running strong but I did suspect a little extra vibration just before I noticed the smoke. Id like to add that I didnt see the smoke until i was rolling up my driveway at the conclusion of my ride. My limited knowledge of motors suggests to me that I may have a major valve problem. Could I be right? Should I start parting it out?...haha. Thanks for any help.

 

[hampshirehog]

Fumes rather than smoke is normal on a hot ride (looks like smoke but isn't if you know what I mean) - that's your breather breathing. They're meant to be 'recycled' via the airbox. You shouldn't be getting fuel up there and I can't see how it would. Was it dripping or was it just a smell of fuel?

 

[TheCafeKid]

I just got back from a ride and noticed smoke coming out from under the seat of my g450. I got down along side the bike and observed very much white smoke and a some FUEL coming out of the breather hose from the valve cover. The hose was not connected to the airbox. Also, the bike felt hotter then it should be, so i checked the oil to find that the crankcase was almost bone dry. I have exactly 79 miles on the bike since the last oil change and I didn't observe any leaks. The bike seemed to be running strong but I did suspect a little extra vibration just before I noticed the smoke. Id like to add that I didnt see the smoke until i was rolling up my driveway at the conclusion of my ride. My limited knowledge of motors suggests to me that I may have a major valve problem. Could I be right? Should I start parting it out?...haha. Thanks for any help.

If its a valve issue, its pretty simple to fix given fairly common tools. I think the only odd ball one you'd need is a valve spring compressor.

 

[sark]

A liquid that smells like gas was definitly dripping out. Whether or not it was gas I do not know, but it is a liquid and it is definitly dripping out. I could see it collecting on the sides of my airbox. And I just can't believe that I burned up so much oil in 79miles.

 

[TheCafeKid]

Well, if there is indeed gas there, you may have it leaking INTO the crank case, thining your oil, and allowing it to pass the seals/rings. Change your filter, check your petcock for correct functionality, and refill with oil. Run it for a couple hundred miles, checking it religiously. If all seems well, change your oil and filter again in about 500 miles. This should remove all the gas from your case. DO NOT run that bike untill you figure out where the oil is going. If there is THAT much gas in the cases, to the point its thinned the oil out enough to enter the combustion chamber, you very well could end up with a quickly toarched top end/bearing set. Check your airbox for signs of a massive amount of blowby re-entering the box.

 

[sark]

Wow thank you for your detailed hypothesis. The problem has progressed though. I replaced the oil and ran it around town. Things seemed ok (no smoke) until i started to hear a mysterious ticking. I rode it to where I needed to be. At this point the ticking had ceased. Once there, i parked it for the night. When I come outside the next morning, it had unloaded some oil into my girlfriend's driveway. After I quick inspection, I believe I saw oil leaking from that orifice on the bottom of the airbox. I tried to crank it but the battery was unable to cycle it even once. The day earlier it had fired almost immediately and it is a new battery. So I pulled the clutch in and began to push, except the bike was very difficult to push while in gear with the clutch lever pulled all the way in. Although, In neutral the bike rolls freely. I'll admit that I haven't the slightest idea of how a motorbike tranny work. I'm about to break into the airbox and see if there is any oil in there.

 

[sark]

Scratch that, it's fuel dripping out of the airbox. I did the 'ol fire test.

 

[TheCafeKid]

Check your petcock. Sounds as if it may be faulty.

 

[sark]

Update: Lotsa of gas came out of the left cylinder when I pulled the carbs off. None came out of the right. My petcock is alright, seems to work ok. Gas come out on "pri" and no gas comes out on "on."

 

[sark]

Ok just peered into the intakes of the head and it's filled to the brim with gas on the left side but not the right. Also, it may be my imagination but the left side looks kinda black/brown/burnt on the walls in there.

 

[TheCafeKid]

Take the plugs out, take the carbs off, and hit the starter button untill the bike pushes all the fluid out. DO NOT, i repeat DO NOT try to start the bike with the plugs or carbs on the bike. You risk hydrolocking it (if you havent already) and bending the crank/connecting rods, and other parts.

Tear your carbs apart, clean and replace orings, AND ESPECIALLY THE FLOAT VALVES, and check your float levels. Dont run the bike untill you do. Period.

 

[sark]

Thanks will do! I'll let you know what i find.

 

[TheCafeKid]

Re-reading your discovery post about the bike not cranking and being difficult to push pretty much worries me that you may have already done some damage. I hope not, but as ive learned recently, filling the combustion chamber with fluid will show you in short order where the weakest part in your lower case is. Hopefully there is no damage yet, but please please do the things that i have outlined. You likely have a very very faulty float valve, and its just letting gas fill into the cylinder. Id replace them both, for both carbs that is. If it was on the side stand, naturally thats where all the gas is going to go due to gravity, but just in case its would be safe to change them both out.

 

[sark]

Ok got all the fluid out (mostly onto my face). The pistons seemed to cycle smoothly as far as i could tell. Does this mean i dont have any bent/distorted internal? Or is that still a possibility? The bike is so hard to push in gear with the clutch disengaged that i can't imagine this didnt have something to do with it. Also the bowl gasket on the left carbmust be bad because i saw fuel all along the outsid perimeter of the bowl.

 

[TheCafeKid]

Ok got all the fluid out (mostly onto my face). The pistons seemed to cycle smoothly as far as i could tell. Does this mean i dont have any bent/distorted internal? Or is that still a possibility? The bike is so hard to push in gear with the clutch disengaged that i can't imagine this didnt have something to do with it. Also the bowl gasket on the left carbmust be bad because i saw fuel all along the outsid perimeter of the bowl.

Its still a possibility, but if they are both cycling smoothly then maybe you got away with one. Its likely hard to push cos the oil is so diluted that its not doing a damn thing, and the clutch plates are sticking. Really should push it in neutral anyway, better on the internals. Just think, youre pushing against all that gear resistance. Anyway, the bowl gasket is self explanitory. Normally, gas never sees the gasket, if the float levels are correct, except maybe in turns. But, they are resistant, not impervious. Sit gas on them long enough, they'll leak. Thats one major drawback to the CVs as ive found out. There is no overflow like the VMs have. At any rate, after doing your carbs, change the oil AND the filter. Run the bike for a few hundred miles. Change it again. That should get all the fuel out of your cases. Good luck man, we're pullin for ya!

 

[sark]

Thanks man! Your help has been invaluable.

 

[Zook]

Sounds like carb needle/seat problem.
Or petcock diaphragm has a leak and gas is being sucked into the intake.

 

[sark]

Hey just wanted to report back. My needle and seat "looked" ok and it was suggested to me that I check my float levels. Sure enough the left carb float was off. I bent it back as best i could. That was about 50 miles ago and everything seems ok, but I still got my fingers crossed. Oh and it rolls just fine now after the oil change. Thanks again everyone, especialy cafekid.

Peace