Anti-spill gas valve?

[GV27]

Hey Guys,

New here - I'm pretty active on some online car forums - don't know why I didn't look for a CBR forum sooner rather than knocking myself out on this problem for months! This is actually a question about a '93 CBR600F2, but I think it's probably the same on all CBRs regardless of vintage. I was told you guys are pretty sharp on wrench questions.

My question is: is the gas tank valve designed so it won't spill if the hoses are disconnected?

Here's why I'm asking:

A couple of years back I got a job where I was traveling at least 3 weeks out of 4 including a lot of weekends. I left the bike to basically rot in the garage. Didn't do a thing to winterize it. I got it fired up about a year ago and it did run, but not very well.

So anyhoo - doesn't need to be a long story! I went ahead and overhauled the carbs to get them unclogged. While I had the tank off the bike I went to drain the old fuel out via the valve underneath (on-off-res). Nothing would come out the valve. I figued it was clogged so I took the valve apart as best I could - it's got a pretty elaborate single peice - and cleaned it out as best I could. Unfortunately my service manual doesn't say anything about the workings of the valve itself. Cleaning out the valve hasn't helped. I've repeated the cleaning several times. I haven't tried to put the tank back on the bike.

So the thought suddenly hit me (and boy will I feel dumb if I'm right!): maybe the valve is designed to not flow fuel when off the bike. Maybe as a safety measure?

So have I been banging my head into a brick wall for the last couple of months, or what? :banghead:

Thanks,

Chris

[RodeRash]

Unlike earlier dirt bikes that required you shut off the fuel when you were not running, most street motorcycle petcocks are vacuum operated. The engine supplies the vacuum. When you shut the engine off, the valve is closed.

[SwampNut]

Those answers are correct, and I'm pretty sure the F2 has that.

In addition the F3 had a fuel pump, not sure about the F2. You should join the CBR mailing list and ask there. cbrlist.com

[mickcbr1100]

Like they said but some of the older bikes also had a PRI(me) position on the tap which would let the fuel out under gravity. To confirm its a vacuum operated tap it will have two pipes coming from it, the larger for fuel the narrower for the vacuum.

[birdie_xx]

The '93 CBR1000F was like that. You could remove the tank without a spill....

Now the XX is a different story (FI model at least) :shock:

And I learned the hard way :oops: .....

Cheers,

[GV27]

So what you guys are basically saying is: :banghead: :banghead: :banghead: !!

Yeah that's it. Gosh darnit. I'm usually pretty sharp mechanically. I can't believe I didn't think of it sooner. 2 hoses, fuel and vaccum. No fuel pump - I know that much for sure!

I've just alwyas been really careful to keep the valve shut and I've never tried to open it off the bike. I can't think now what I thought the little hose was.....pretty freakin' obvious now that I think about it! :banghead: I've carefully reattached it probably 20 or 30 times without ever thinking about what it was there for.

Thanks a bunch guys. It was 50-60 deg here all week. I'll have to get that girl fired up soon! I'd pretty much given up in frustration.

Chris

[RichardCranium]

The '93 CBR1000F was like that. You could remove the tank without a spill....

Now the XX is a different story (FI model at least)  :shock:  

And I learned the hard way  :oops: .....

Cheers,

Ditto. That shit comes out fast too.