fuel petcocks on tank and under.

farmerdave · Post by **farmerdave** » Tue Apr 15, 2008 12:39 pm

have a question about starting. Takes about 1 to 2 minutes of cranking to start my 82 CBX. A person said that I need a new petcock for the fuel, is it the one on the tank, or the one under the tank that has the 6 six lines coming off of it. Any help would be great, Thanks

alimey4u2 · Post by **alimey4u2** » Tue Apr 15, 2008 12:54 pm

farmerdave wrote:have a question about starting. Takes about 1 to 2 minutes of cranking to start my 82 CBX. A person said that I need a new petcock for the fuel, is it the one on the tank, or the one under the tank that has the 6 six lines coming off of it. Any help would be great, Thanks

Welcome to the site Dave....

The fuel petcock is directly underneath the left hand side of the tank. You may not need a new one, it may well be the filter (inside the tank which is connected to the petcock) is partially blocked. I would check that first before spending money as it is easily cleaned. Th six tubes you refer to are carburettor overflow tubes. As a side note, are you sure your choke butterflys are closing properly prior to starting ?? Hope this helps & please keep us updated with feedback...

EMS · Post by **EMS** » Tue Apr 15, 2008 1:59 pm

I think he talks about the vacuum valve on the Prolinks, which some people call a petcock

. This valve cuts the fuel flow off, if it is not opened by engine vacuum. Theoretically, it may need replacement, but you can actually remove it completely, plug the vacuum line and run the bike without it. It is only there to prevent ongoing fuel flow into the float chambers when the engine is stopped.
Because of this device, Prolinks are notoriously hard starters, if they have sat for a while, because you have to crank the engine in order to fill the float chambers in case they are dry or almost dry.

Sorry

Welcome farmerdave

Hope you will enjoy the site!

alimey4u2 · Post by **alimey4u2** » Tue Apr 15, 2008 2:13 pm

Good backup Mike....

farmerdave · Post by **farmerdave** » Tue Apr 15, 2008 3:06 pm

Thanks for your input, will look at the petcock on the tank. The reason taht I called it a petcock, because in Honda's part system, they are both call the samething. Will look at both and let you know how I make out, will be in a couple of weeks. Dave

CBXRoger · Post by **CBXRoger** » Tue Apr 15, 2008 7:42 pm

Those of us with the late model CBX's with the vacuum fuel shut off under the tank, have learned many ways to get the engine to fire up.

Dave McMunn runs his bike out of gas as he coasts into his garage. The bike will run for a mile on the fuel in the floats and lines. Then when you go to start up, turn on the fuel tap, and crank the engine for a few seconds. This will create vacuum to open the flow of fuel. Do this a few times to fill all the floats. Then turn on the choke and the engine will start.

The advantage is that you now have fresh fuel in all the carbs.

Roger

Rick Pope · Post by **Rick Pope** » Wed Apr 16, 2008 7:20 am

Dave Ditner has an even better way to fill the bowls.
On the back of the vacumn shut-off is a nipple, or vent, opposite the vacumn port. Put a long length of vacumn line on that nipple and blow gently. The valve doesn't care if there is vacumn, only that there is a pressure difference, and so the fuel will flow. Coil up the length of line and tuck it under the tank until next time and ride.

Rick Pope · Post by **Rick Pope** » Wed Apr 16, 2008 7:23 am

Oh, and if Farmer Dave is really a farmer, he should be out planting crops instead of playing with bikes.
Gotta go top-dress (fertilize) some wheat this morning.....

The International CBX Owners Association

fuel petcocks on tank and under.

fuel petcocks on tank and under.

Re: fuel petcocks on tank and under.

Thanks for your help and input

Late Model