Crankcase filled with fuel...help!!

[tcrave]

Originally Posted by Gz Rider

I'm not sure of exactly what happend when but I don't think tapping of the float caused any part of your problem.

As I understand it the system works something like this:

Fuel sits in your fuel tank and is held back by a vavle in the petcock. The engine provides vacuum to the petcock via a small tube in the back if the petcock. This vacuum opens the vavle while the engine is turning or cracking and the fule runs into the carb bowl.

The fuel raises the float in the bowl until the float rises so high that is causes a vavle/needle to shut off the flow of gas. The carb has lots of little holes/jets that then stuck the gas out of the bowl and into the intake for combustion. The float drops from lack of gas and the vavle/needle opens again allowing more gas into the bowl.

In your case it seems like two things had to have happened. First, your petcock seems to have failed because you describle fuel flow without the engine turning. That shouldn't happen.

Second, even if fuel does flow when it shouldn't, the float in the bowl should cat off the flow prior to overflowing the bowl. Tapping on the bowl could cause the malfunctioning vavle/needle to reseat itself and cut off the fuel and that would be a good thing. I can't see any harm comming from tapping the bowl.

All I see happening is that the two items failed (probably one failed quite a while ago) allowing your float bowl to overflow and once it did that the gas flowed into the cylinder and then into the crackcase. With the crackcase filled with oil and gas the cylinder was hydrolocked.

I have to say I was very impresses with Blaine's diagnosis given the description (no offense to you). It sounded to me at first read like you bike had become possessed by the devil!

Now go apologize to your buddy for ever having doubted him.

Ahhh...I actually have an idea now that you mentioned the vacuum valve. I was wondering what that was, I thought it might have been a vacuum, but wasn't sure. I took the petcock off and took it apart and everything in there looks fine. I saw some dirt on the filters attached to the tubes, but nothing beyond that. All the gaskets seemed fine and everything. I looked at the petcocks channels and realized there is nothing in the petcock to hold the fuel back...so I was wondering what the hell holds the fuel back, then I saw that tube. I am wondering if maybe the vacuum pressure in the tube actually holds the fuel and PREVENTS it from coming out and going into the carb?? Then onces the engine is running maybe the pressure stops and lets the fuel run?

I really did not see a single thing in the petcock that would stop the flow of fuel...that kinda scares me...well, I take that back, there was a little disc with a spring loaded...maybe that has something to do with it...but it looked fine to me, so I don't know how that could have failed.

I am wondering that maybe if my theory is correct, maybe the vacuum hose got disconnected and didn't provide the suction needed to prevent the fuel from flowing? Or maybe the vacuum fell off in the open position?

So it hydrolocked bad? Is it repairable?

Yes, I agree, blaine did a great job, so did you.

Well, I never accused him of doing anything wrong, that was just a theory I kept to myself. He is a diesel mechanic and knows just about everything there is to know about gasoline engines as well...and so does his dad, and both of them where there. He suggested to me not to mess with the carb and just to drain the crankcase out, put fresh new oil in it and a new oil filter, change the spark plug, and go from there. (provided that I had already drained the airbox.) I really would like to clean the carb, but at the same time, I don't want to do more damage that I need to. I have never taken a carb apart before so I only have a slight idea of what I am getting myself in to.

Thanks for you help!!