Stuck float

[balky1]

Ya I noticed fuel dripping out from between the carb and the airbox. My oil level is much higher now too. Luckily I haven't ran it since it's leaked. I'll just drain the oil and replace when I get the carbs straightened out

Hey, one advice. After you changed your oil and fixed the leaking petcock/carbs still DO NOT CRANK THE ENGINE! First remove all the spark plugs and crank it with them removed to spill out the fuel if the cyllinder was/is overflowed. If you don't do this and your cyllinder is full, you will hydrolock it and end up with bent connecting rods at best.

Ivan

[ribbert]

Ya I noticed fuel dripping out from between the carb and the airbox. My oil level is much higher now too. Luckily I haven't ran it since it's leaked. I'll just drain the oil and replace when I get the carbs straightened out

Hey, one advice. After you changed your oil and fixed the leaking petcock/carbs still DO NOT CRANK THE ENGINE! First remove all the spark plugs and crank it with them removed to spill out the fuel if the cyllinder was/is overflowed. If you don't do this and your cyllinder is full, you will hydrolock it and end up with bent connecting rods at best.

Ivan

Safe advice Ivan but it's probably faster just to turn the engine over by hand to make sure it's free.
The fuel won't sit in the cylinders for long anyway, being thin, it runs past the rings, that's how the crankcase fills up.
There's also a good chance it runs past the rings faster than it leaks in, the flow rate from the offending carby not being very high.

I've actually only ever seen one example of hydraulic locking of a cylinder causing damage. An H2 Kawasaki (2 stroke) lying on its side for half an hour following an accident then immediately trying to bump start it down a hill as soon as it was stood upright - bent crankshaft.

The rider was not only stupid enough to crash it but stupid enough not to have considered that possibility - and he should have known better!

Noel

[balky1]

Ya I noticed fuel dripping out from between the carb and the airbox. My oil level is much higher now too. Luckily I haven't ran it since it's leaked. I'll just drain the oil and replace when I get the carbs straightened out

Hey, one advice. After you changed your oil and fixed the leaking petcock/carbs still DO NOT CRANK THE ENGINE! First remove all the spark plugs and crank it with them removed to spill out the fuel if the cyllinder was/is overflowed. If you don't do this and your cyllinder is full, you will hydrolock it and end up with bent connecting rods at best.

Ivan

Safe advice Ivan but it's probably faster just to turn the engine over by hand to make sure it's free.
The fuel won't sit in the cylinders for long anyway, being thin, it runs past the rings, that's how the crankcase fills up.
There's also a good chance it runs past the rings faster than it leaks in, the flow rate from the offending carby not being very high.

I've actually only ever seen one example of hydraulic locking of a cylinder causing damage. An H2 Kawasaki (2 stroke) lying on its side for half an hour following an accident then immediately trying to bump start it down a hill as soon as it was stood upright - bent crankshaft.

The rider was not only stupid enough to crash it but stupid enough not to have considered that possibility - and he should have known better!

Noel

Yes, turning it by hand is also a possibility. But since I was too lazy for that I did it my way. Also it would be much easier to turn it by hand with spark plugs removed. :-D
Oh, and it happens a lot more than you think that a cyllinder gets full of gasoline (not even needed for it to be full, it is enough that the volume of gasoline inside it gets higher than the rest of the volume you get in the cyllinder on the compression stroke since the liquid is incompressible, if you get me). I've seen it happen often when such overflowing happens. For a precaution, I would deffinitely do it. Two minutes to remove the plugs can save a lot of money.   

[jscgdunn]

Do you have that picture to show us of your fix on the float tab?

We really need to put that in the Files.

Noel

Pat,
You nailed it in my case.  My float has exactly the same divot as in the pic.  Strange how it did not leak one day but started the next!

Jeff

[Pat Conlon]

Thanks Jeff, but the credit goes to Noel. 

[twangin4u]

Consider buying a new petcock.

With your engine off, no vacuum, that petcock should not let any gas thru to your carbs.

Forgot I needed to update my picture. Lol. I traded my '84 for a '91. No vacuum petcock on this one. It did have a manual petcock valve on it.. Until mice decided to sharpen their teeth with it. Now it's a nub.
Thanks to new needles and seats it hasn't leaked a drop since. Pretty happy about that. Ever just dumped 4 gals of gas on the floor of your garage? Sucks. Especially when it's the first thing you see/smell when you wake up in the morning. Lol

[balky1]

Consider buying a new petcock.

With your engine off, no vacuum, that petcock should not let any gas thru to your carbs.

Forgot I needed to update my picture. Lol. I traded my '84 for a '91. No vacuum petcock on this one. It did have a manual petcock valve on it.. Until mice decided to sharpen their teeth with it. Now it's a nub.
Thanks to new needles and seats it hasn't leaked a drop since. Pretty happy about that. Ever just dumped 4 gals of gas on the floor of your garage? Sucks. Especially when it's the first thing you see/smell when you wake up in the morning. Lol

I know the feeling. I had some celebration with my friends, allready a bit drunk, and then smelled the gas throught the window. Imagine that tank removal. 

[FJ_Hooligan]

A better way to get fuel to dump out of the cylinder is to pull the plug, put it in gear, and use the rear wheel to turn the motor over backwards.

Any fuel left in the combustion chamber will get pushed out the exhaust valve rather than compressed.

Of course, this technique assumes that the cylinder filled up because the intake valve was open.

Will fuel leak past a closed intake valve?

[FJmonkey]

A better way to get fuel to dump out of the cylinder is to pull the plug, put it in gear, and use the rear wheel to turn the motor over backwards.

Any fuel left in the combustion chamber will get pushed out the exhaust valve rather than compressed.

Of course, this technique assumes that the cylinder filled up because the intake valve was open.

Will fuel leak past a closed intake valve?

Fuel will most likely leak past the cylinder rings and into the oil sump. Take the plugs out to be safe, it may be less expensive.

[twangin4u]

Ya I noticed fuel dripping out from between the carb and the airbox. My oil level is much higher now too. Luckily I haven't ran it since it's leaked. I'll just drain the oil and replace when I get the carbs straightened out

Hey, one advice. After you changed your oil and fixed the leaking petcock/carbs still DO NOT CRANK THE ENGINE! First remove all the spark plugs and crank it with them removed to spill out the fuel if the cyllinder was/is overflowed. If you don't do this and your cyllinder is full, you will hydrolock it and end up with bent connecting rods at best.

Ivan

Ya that was actually the first thing I did. I took plugs out and carbs off and blew though both sides with compressor. Id say about two cups of gas cans gushing out the intake. Good call. Thanks. All is well now. She purrs like a kitten

[balky1]

That's always the best prize you can get. 

[ribbert]

A better way to get fuel to dump out of the cylinder is to pull the plug, put it in gear, and use the rear wheel to turn the motor over backwards.

Any fuel left in the combustion chamber will get pushed out the exhaust valve rather than compressed.

Of course, this technique assumes that the cylinder filled up because the intake valve was open.

Will fuel leak past a closed intake valve?

Hooli, I believe the manual says, and it's a golden rule of chain/belt drive OHC engines not to rotate the engine backwards.

Re your question "Will fuel leak past a closed intake valve?"

I suspect you already know the answer to this, no, it won't if your seats are in good nick.

I have been using this method of checking valve seats (intake and exhaust) for nearly 50 years. With valve closed, fill the port with petrol and leave. If fuel shows up, valves seats are crook.
A well seated valve will not let petrol pass.

Noel