SRX Gas siphoned into oil tank?

R

red_smoke

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Here's an odd one for you guys... 1998 SRX600 with 2500miles. I just went through the carbs and got everything running and lubed for the season. Filled the gas tank with 8 gal of 93octane and moved it into a heated garage. After a couple days in the garage, we walk in to find a quart of gas on the floor and the oil tank is full of gas and running out the vent tube. We pulled the plugs and the cylinders aren't full, but we did notice that the gas tank cap had a bunch of pressure when we loosened it.

So what's the thoughts? Are the vent tubes for the fuel and oil systems connected somewhere? My guess right now is that the fuel cap isn't vented and the expansion in the tank somehow forced the fuel into the oil tank... but how? :o|
 

vent lines are usually under the handle bar pad.Check if it has been crimped or plugged.That is a scary situation if you ask me.Lucky no one came around and tossed a cig. butt on the floor..
 
I had the same problem with my SXR 700. What happen is that I had my gas tank off & when I re-installed it I pinched the vent line & that caused the gas to go into the oil tank. For sure you have a pinched vent line somewhere.
 
X2 on plugged/pinched vent line as well as a possible fuel pump problem. As gas warmed up it expanded, with out vent it pressurized fuel pump. Floats stopped it from entering engine. Instead it pushed the oil out of the oil line back into tank and then overflowed oil tank. Could have ben tragic if your oil tank had ben low and didnt overflow. Fire it up and BURN DOWN/BOOM. Going to need to flush and bleed oiling system prior to riding!
 
Same thing happened to my good buddies Thundercat. but unfornutaly he was on the trail when it happed. Seized up soild. We threw a bunch of oil in the tank and he was able to drive it back to the trailer after it cooled down. but he scuffed a cylinder. Not a good day on the trails that day.
 
i did this once, it sat out front of the sop and pushed oil out the overflow so much that it soaked the foam in the handlebars and covered the gas tank shroud and running boards. what a mess.
 
Appreciate the replies guys. Went thru the system today and flushed everything out. Didn't find a problem with vent lines down below but based on the responses it's probably in the rat's nest squeezed together underneath the handlebar pad. Will dig there next.

Sad thing is I'm usually on the 4-stroke side for RX1 problems... rarely touch the old 2-stroke except for every fall when I go thru 3-4 plugs trying to get it to start and run reliably after the summer shutdown. After that, she's good for the season! :2strokes:
 
Probably not the best for your health but low tech way of checking is pull that rats nest apart. Figure out one is for gas tank, put your mouth in the filler hole and blow. Should be able to feel air coming out of line. May have ben something as stupid as condensation froze in vent line and didnt melt fast enough to release pressure build up. If you have an air compressor you can get a blow nozzle and wrap rag or whatever around it BUT be careful as if your put to much pressure on it you have the sequel to your first experience or worse.
 
yeah those nests are bad,usually they end up chewing up all kinds of wire in there also.I had to fix numerous wire on my 2 sleds when the mice nested in the handlebar pad years back.Bare wires were grounding out on the frame and such.Now I remove all foam from the sleds fro the summer.Fixing the wires in a tight spot was no fun.
 
Happened to my dads viper last year. Had the rear end up in the air over night and came out to gas all over the floor. The crank case was full as well. Took the exhaust off and it was full of gas too. Dried everything out and same thing the next day. Ended up being a bad fuel pump. i assume there was a hole in the pump membrane that allowed the fuel to go back into the vacuum line. Id say pull the pipe and plugs and slowly pull it over by hand to be sure your crank case isnt full. Then check the fuel pump.
 
sxr1000 said:
Has anyone seen the pump and carbs fill up with oil? I have seen two sleds this year with this.
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Happens every year with my friends 98-SRX7. We have to pull the carbs and clear all the oil. He needs to replace the brass 1-way check ball things I am guessing. It takes all summer, but they do fill with oil.
 
NY_SXR700 said:
Happens every year with my friends 98-SRX7. We have to pull the carbs and clear all the oil. He needs to replace the brass 1-way check ball things I am guessing. It takes all summer, but they do fill with oil.
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yes, the 1 way check valves are bad in the lines, make sure when you put in new ones to pay attention to the arrow on them when you remove and reinstall, its for the flow direction.
 
Dont the check valves point twordes the fuel pump? so how could they be bad? oil is supposed to flow to the pump or do they shut and not let oil flow when not on use?
 
Sweet picture man! Viper lights in two stroke smoke! :D

JDViper said:
Happened to my dads viper last year. Had the rear end up in the air over night and came out to gas all over the floor. The crank case was full as well. Took the exhaust off and it was full of gas too. Dried everything out and same thing the next day. Ended up being a bad fuel pump. i assume there was a hole in the pump membrane that allowed the fuel to go back into the vacuum line. Id say pull the pipe and plugs and slowly pull it over by hand to be sure your crank case isnt full. Then check the fuel pump.
Click to expand...
 
sxr1000 said:
Dont the check valves point twordes the fuel pump? so how could they be bad? oil is supposed to flow to the pump or do they shut and not let oil flow when not on use?
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if the valve is bad or stuck open it will let fuel go back into the oilpump and fill the oiltank with fuel. the fuel is larger and has more weight so it pushes the oil back into the tank, more liquid is heavier then less liquid.

the oil is mixed in the fule pump so that how it pushes back thru the oilpump and lines into the oil tank.

theres a yamaha service bulletin on this, dont remember what year but its in the tech manuals.
 
mrviper700 said:
if the valve is bad or stuck open it will let fuel go back into the oilpump and fill the oiltank with fuel. the fuel is larger and has more weight so it pushes the oil back into the tank, more liquid is heavier then less liquid.

the oil is mixed in the fule pump so that how it pushes back thru the oilpump and lines into the oil tank.

theres a yamaha service bulletin on this, dont remember what year but its in the tech manuals.
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Mrviper statement is true to this thread topic, not so much applys to sxr1000 post on this thread about fuel pump and carbs filling with oil. Fuel pump and carbs filling with oil would either be fuel pump malfuntion and letting straight oil weep threw pump or gas evaporating and leaving oil behind.
 
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