80 AUTOMATIC FUEL VALVE

[EMS]

. . . . . or, just put a '79 valve on your '80 or ProLink ;)

Don

You just take out the vacuum valve. The petcock remains and feed directly into the carbs.
But some people like their bikes original.

[bdento59]

I know a lot of people do not have problems with it and claim their bikes fire right up, but....
My Prolink is a lousy starter after sitting for a longer period of time.
I blame it on the vacuum valve.

IMO&E, your blame is well directed. That's also why I defeated my vacuum valve, depending now only on my (not yet failing) memory to turn off the gas every time I turn off the motor. Invariably, when I turn on the fuel tap in preparation for flight after the bike has been sitting for even just a week, the fuel can be seen to flow vigorously through the filter for 20-30 seconds before the float bowls are full again. After that, a few full pulls on the throttle to prime with the accel pumps, full choke and she fires up quite readily. I am a happy camper.

[Dave Ditner]

There's an easy way to prime the carbs and save the battery and starter. I wrote it up in a previous issue of the Xpress. You don't need to disable the valve either. Cost about $5.00. What you do is find the vent line for the valve. It exits the bike with the overflow hoses on the rh side, if I remember right. Pull it up out of the clip and cut the end off of it so it will curl up behind the rh side cover. Then go to your medical supply store and buy a replacement pump bulb for a blood pressure cuff. Stop at an auto parts store on your way home and buy a plastic vacuum fitting, 1/8" on one end, 1/4" on the other. Plug the 1/4" end into the bulb, the 1/8" end into the end of the vent hose and give it a couple of pumps. It should hold pressure. If not check the vent hose end for brittleness or tears. Cut it again if you h ave to.
How it works. Pressure on the vent side of the diaphragm is like vacuum on the working side. Fuel flows. Hold pressure for three or 4 minutes or so and you should fill the carb bowls. It should start rignt up. Your battery and starter will love you.
I run my carbs completely dry at the start of every winter. I fire it up with the fuel selector off, run it till it coughs, choke it, work the throttle to empty the accellerator pump and passages, until it dies completely. Then open the drains to get the last drops out. In the spring or after it's been sitting awhile, I pull the side cover hook up the pressure ball pump it up some, hold it for awhile light it up and go for a ride. Been doing this for at least 5 years and haven't had to clean a carb yet.

[Jeff Bennetts]

To follow up on Dave's post, the secondary reason for hard starting is that 75% of the CBX's out there that have not had the carbs cleaned lately have clogged Accel pump nozzles, you can pump the throttle all day long and if the fuel can't reach and pass through the nozzles NO priming is going on.

You can check them by pulling the tank, removing the carb tops and slides, pump the throttle, check the throat of the carb and if its dry then they are plugged. The other method is to tilt the motor, pull the air box and plenum off and visually check each nozzle while pumping the throttle.

Now of course the carb bowl with the pump that feeds the nozzle needs fuel in it before you can check the nozzles, you can do this with all yrs by bypassing the vacuum shutoff and just filling the carbs at the carb inlet.