Gasoline gushing from crankcase

It seems I have an interesting problem. When I crank my XJ650 gasoline begins to pour from the crankcase output shaft. I've never encountered something like this and I'm not terribly sure how the gas found its way down into my crankcase in the first place. Any suggestions??

 

You may stuck floats, and possibly a bad petcock.

 

Stuck float!!!! Carbs need to be rebuilt if they already haven't been done!!! Do not run that bike until problem fixed.

 

Just went through this myself. DO NOT run the motor. Gasoline leaked past the needle and seat in the carbs and down into the cylinders, leaking past the rings and into the crankcase. Your oil is now mostly gasoline.
Put some sort of clamp on the fuel line. Drain all of the oil and get a carb rebuild kit. Once I did mine, I bought an inline shut off valve and I shut the fuel off every time I park the bike just to be safe.

 

After you drain the crankcase, run some cheap oil in it. Let it heat up, but don't ride it then drain. Refill with the good stuff and new filter. What ever you DO NOT pull the plugs and crank the motor over unless you want a fire. Don't ask how I know.

 

But Thrasher now we really want to know "how you know"...

 

Thanks for the help. I've installed an on/off valve and changed the "oil". I'm just waiting on that rebuild kit and I should be back on the road.

 

You found the "Molotov cocktail" feature of the XJ petcock !!

It takes BOTH a faulty petcock AND at least 1 sticky needle/seat/float to flood the crankcase - - just wanted to add that the glue on the oil filter has been compromised, you can stick a couple magnets to the new filter, and that many people have "rinsed" their engine with no ill effects.

 

why the heck dont these carbs have overflow tubes , i've had several hondas and all of them had overflow pipes routed to under the rear of the engine,
you can then see in an instant if a float sticks, without it flooding the engine
stu

 

Yeah all my Kaws would piss fuel on the ground underneath if a carb couldn't control the fuel...

When I first got this one, the PO said it hadn't run in at least four years that he knew of. First rough clean of the carbs just to find out if it actually ran or not, one stuck and I noticed it right away...and realized that meant the petcock was hosed as well...

But who knows how many times that had happened before I got it...first order of biz after making that stop was to change the oil...I used a pan that should have easily held a gallon...I didn't think the oil was ever gonna stop coming! It filled it right to the top, to where I had to skim some off just to be able to move the pan. Probably a 50/50 ratio of fuel/oil!

As I posted, I put one of those $5 lawn equipment petcocks in the line until I can get around to working on the petcock...but the carbs no longer have the problem of sticking.

 

Some XJs do, some don't.

If your carbs are in a proper state, it's not an issue.