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Discussion Starter · #1 ·
Hopefully someone will recognize what is going on with my 1995 900 SS/CR.

I have not ridden in several weeks due to heavy work schedule. I went out to ride yesterday and tried to start the bike and the battery was almost dead, not quite enough juice to crank, but I did get a loud pop and some wispy white smoke out of the exhaust. I put the charger on it for 24 hrs.

The bike started right up today but . . . While allowing the bike to idle as I was putting my jacket on, I noticed a lot of fluid raining down from my engine. I shut the bike down and found it was a brownish liquid that smelled like gas, a bit thicker than water, coming from the drain hole on the front left side of the air box. This stuff was pouring out.

I took off the airbox cover and filter and the inside of the airbox had a couple of ounces of this liquid, pouring through the drain hole. I dried out the airbox, rinsed the lower half of the engine off so it would not go up in flames when the exhaust got hot, and started it up again without the air filter so I could see what was going on.

Again, the bike started right up, but after a couple of seconds this brownish gas smelling liquid started pouring into the airbox from a thick black rubber hose on the left side. I cleaned it out again to prevent a fire and tried again, the same thing happened. When I shut the engine off, there was a whispy white smoke coming from the tailpipe again.

I have no idea what is going on here, anyone have any ideas? I really want to go for a ride, but not if I am going to go up in flames. :eek:

Thanks!

Patrick
 

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Old Wizard
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3,007 Posts
Blow-By

Piston rings act as a seal between the high pressure created in an engine’s combustion chamber and the lower pressure in the crankcase. Blow-by occurs as the rings become worn and they allow a small fraction of combustion gases to leak into the crankcase.

The consequences are accelerated contamination of the engine oil, as well as excessive release of hydrocarbons to the atmosphere, unless a crankcase ventilation system is used to route the gases back to the engine intake to be burned.

On Ducati engines, excessive blow-by can cause unusually large amounts of entrained engine oil to be forced through the crankcase ventilation system and into the airbox. It’s not unusual however, to occasionally see a light deposit of oil in a Ducati airbox.

Blow-by occurs in all engines to varying degrees as they wear, but when it becomes excessive, an engine rebuild with new piston rings is in order.

Your first step, of course, is to check the sight glass to make sure you haven't overfilled your crankcase which can trigger the expulsion of excess oil. Further, if the fluid is brownish you may be leaking coolant into your oil, perhaps via the water pump seal. This will contaminate the oil and will raise the fluid level in the sump.
 

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Premium Member
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923 Posts
What SHAZZAM wrote ,,,

But also consider ,,,,,,,,,
It's a carburettored bike
A few weeks of not being ridden
Possibly float needles stuck/not sealing
Engine getting partially flooded by excessive fuel
Some of that fuel getting past the piston rings, contaminating the oil
Thinned oil gets back past the rings much easier than pure oil

Check your oil level ,,,, and feel it, smell it ,,, checking for fuel contamination.
If it's risen ,,,,, there's your answer.
 

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As Shazzam and Latte said,Check your oil level[I'll bet the window is completely covered] to see if it has risen.You have had a float needle stick and your crankcase is full of fuel. Do not run it like this,big fire is possible if it backfires. Change the oil and filter. the ideal next step would be to remove the floatbowls,floats, and float needles.Likely a tiny piece of crap has lodged between the needle and its seat.Sometimes just tapping the floatbowl firmly with a screwdriver handle will dislodge the dirt but on the 900 you can't really see if the leakage has stopped so removal is the best way to go. It is a really good habit to turn the fuel off if the bike is going to sit for much more than a hour or so.
 

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Discussion Starter · #6 ·
Thanks for the help guys. I will check these things out tomorrow after work, as I was out of town today.

My thoughts after reading your posts . . . I think the needles sticking makes sense in this situation because 1) when I left the bike overnight on the charger, I mistakenly left the choke engaged and 2) I've never used the fuel shutoff valve since it is a pain in the butt to get to at the end of a ride, and I have heard of tanks developing a leak from stress breakage at the hinge.

I know it's not a problem with coolant getting into the crankcase because it is an air cooled bike. :)

It could be blow by I suppose, but I had the bike in for service about 1,000 miles ago and they said the compression was fine. Am I wrong to think that if the compression is within spec, that the rings are seated properly and are not overly worn or subject to severe blow by?

I will check the oil level and take a sample and if it is full of gas I will change it out and put on a new filter and see if that solves the problem. If it does, then I can take the float bowls off and give the carb a cleaning, and will start using the fuel shut off valve in the future.

Anybody here ever run into issues with the tank leaking where the hinge is welded to the back of the tank or is this not really a concern?

One more thing, following the rubber tube out of the airbox, it leads to two plastic boxes under the seat. Should I clean them out somehow to make sure all the gas it out of there? I really don't want to catch this bike on fire while I'm cruising down the street.

Thanks again for your help guys!
 
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