Isn't there a simple way to really shut the gas off? I'm thinking some kind of simple on/off small in-line petcock just below the tank maybe. :dunno_black: I hate to have gas just sitting there in the float bowls and jets if I have to leave it for a few weeks. Any idea's?
http://gs-500.info/index.php?title=Convert_petcock_from_vacuum_to_manual
Once you shut the bike off you can always just drain the float bowls. It only takes about 2 minutes for the whole process, most of which is just time waiting for the gas to drain. Technically having an actual shut off isn't going to help you empty your carbs when you park the bike, unless you turn the gas off before you get home and let it drain the carbs as your ride home, but you'd have to be a math genius to time that perfect, and even then I don't think the carbs would completely empty themselves, I think the bike would just stop running.
Acid, I read through that link you posted and I see that switching the selector valve around turns the pri to off, and switches the on/res. and that there's no vacuum needed for the gas to flow. Does the PRI still let gas through if the gas is on, or does it completely shut it off, regardless of the engine running or not? I might be interested to try that next time I have my tank removed.
Quote from: rger8 on April 21, 2010, 08:48:47 PM
Isn't there a simple way to really shut the gas off? I'm thinking some kind of simple on/off small in-line petcock just below the tank maybe. :dunno_black: I hate to have gas just sitting there in the float bowls and jets if I have to leave it for a few weeks. Any idea's?
There's a valve/petcock just under the tank where the two fuel lines attach to the tank. You can turn the knob with a flathead screwdriver. Fuel flows when the knob is vertical, fuel doesn't flow when the knob is horizontal.
Is that what you're talking about?
You can turn this off, and then run the bike till it dies, if you want...but you have to lift the tank to turn this valve off. Unless you're REALLY good...
Quote from: tt_four on April 22, 2010, 05:05:05 AM
Acid, I read through that link you posted and I see that switching the selector valve around turns the pri to off, and switches the on/res. and that there's no vacuum needed for the gas to flow. Does the PRI still let gas through if the gas is on, or does it completely shut it off, regardless of the engine running or not? I might be interested to try that next time I have my tank removed.
tt_four: i do believe the "PRI" becomes a complete shut-off, so no gas flows to carbs when parked. i think i'll be doing this today! haha
edit- i get it now, inside the petcock the rotation puts the new "PRI" to where the original "ON" was, so if a vacuum is put to the petcock, theoretically it would allow fuel to flow, right?
do you think they just removed the vacuum line from the carb to the petcock since it's no longer "needed" for the flow of fuel?
Quote from: sveach on April 22, 2010, 07:59:12 AM
There's a valve/petcock just under the tank where the two fuel lines attach to the tank. You can turn the knob with a flathead screwdriver. Fuel flows when the knob is vertical, fuel doesn't flow when the knob is horizontal.
Is that what you're talking about?
You can turn this off, and then run the bike till it dies, if you want...but you have to lift the tank to turn this valve off. Unless you're REALLY good...
All you need is a long screwdriver. Tank does not need to be lifted.
Picture by Kerry (petcock is ON in the picture. Turn 90 degrees either direction to turn OFF):
(http://www.bbburma.net/MiscFotos/100_1485_TankPetcockInONPosition.jpg)
i'll be doing a test of the mod today if i can.. or within this week depending on when i get all my parts in. =P
good luck to anyone else that plans on fiddling with their petcock.. kekeke
Quote from: DoD#i on April 22, 2010, 09:25:22 AM
All you need is a long screwdriver. Tank does not need to be lifted.
a REALLY long screwdriver. I tried this for 5 minutes with a long screwdriver the other day and wasn't getting anywhere. Maybe I'll try to find a longer one.
even with along screwdriver it is still hard to turn the screw since you have the other fuel nipple in front of it. i gave up and unscrewed the tank.
Would I need to cap the vacuum nipples coming off the petcock and carb if I do the in-line petcock?
I would definitely cap it off on the carb. The petcock won't really matter, but I'd do it just in good taste.
Oh, and make sure to take some more pictures and let us know how it works out. If I hear good confirmation I'll do it to mind. I'm just curious why I've seen so many people replace theirs, but NEVER heard of anything doing this before.
crf 250 petcock? 1-2 plastic 1/4" fuel switches.
isnt the purpose of the factory petcock/vacuum to shut the fuel off when not running?