Auto valve question

[cross]

There is a connection on the front of the auto valve, toward the carbs that nothing is connected to.
Is this just overflow, drain, or?
Should i attach hose to it, plug it or just leave it like that?
If you see on the diagram, hose #5 is the one i do not have on my bike.
Diagram does not show where that hose is connecting to so it may just be drain.
Anyone know?

[EMS]

It is indeed an air vent tube. A hose is not necessary for correct function, but may prevent contamination finding its way inside the diaphragm.

[cross]

Cool, i'll get a hose and attach it but where does the other end go? Just below the carbs?

Thanks

[daves79x]

On the '82 it makes a right-hand turn then lays over the right side of the airbox, down the inside of the right frame tube, then exiting where the rest of the tubes are by the centerstand. It's a pretty long hose. I leave the end where I can reach it to help starting. Blowing into the hose will unseat the vacuum valve and allow fuel to flow, filling the bowls quickly.

Dave

[cross]

Cool,
I bought enough hose to replace all vacuum and carb drain hoseshoses, should be plenty for all.
Thanks once again, you guys are great!

[cross]

I think that my auto valve is not functioning properly.
I tested it per manual and fuel was flowing only on the shorter hose, left bank. I'm not sure if the right bank is getting enough fuel.
Right bank pipes are not getting as hot as the left bank pipes.
I'll try installing the clear hoses so i can see how much fuel is flowing out.
Right bank plugs get fouled quickly, I clean them and it runs normal for few minutes, all pipes get warm but not for long.
Spark is good, new plugs, what else am i not doing that i should?
Are auto valve diaphragms available to rebuilt it?

[steve murdoch icoa #5322]

Dave will be along to get you the right answer but it could be the choke is not operating in synch between the two banks of carbs.
The springs can get bound up with crud or not installed properly after a rebuild.

[EMS]

Sasha:

I cannot find any part number listing for repair parts for the vacuum valve. Ever so often, they pop up NOS on ebay and you could replace the complete unit.

http://www.ebay.de/itm/Honda-CBX-1000-a ... 139wt_1399

I am not sure what exactly the issue would be, if you get fuel to one side, but not enough to the other.
There is always the radical solution, and that is eliminate the whole thing. As a result, your bike will also start a little easier after it parked for a longer time. You just need to be dilligent and close the petcock at the tank every time you park the bike to prevent a possible overflow of gas into a cylinder. Due to the different overflow tubes on later models, however, this is a smaller danger anyway than on the early 79s.

There are some non-U.S. models that had the vacuum closing function integrated in the tank mounted petcock and for these, there are repair kits, which include a spring and a diaphragm, but I don't know if the parts would work on the CBX.

[cross]

Thanks guys

[daves79x]

I think your valve is fine - sooty/fouled plugs on 1-3 would indicate a choke problem, as Steve said. Unless you have a blockage somewhere, the valve opens both outlets at the same time.

Dave

[cross]

Its very possible, i opened the valve and it looked ok.
It actually is the right bank, 4-6 that are problematic.
But its probably the same issue.
I have to take them off tonight.
Any tricks on removing the sprocket center bolt?

[tevan]

Impact is what I use....

[daves79x]

Hold the rear brake, or just loosen the adjusters.

dave

[cross]

Well, who knows, knows! Thanks Steve and Dave for the tip!
I started taking things apart and noticed that cable on choke lever is loose!
The plate that pinches cable housing is lose and of course, choke was still on.
I attached it and made sure choke mechanism on the carbs is moving as it should, cleaned my plugs and now it's running on all six! Not all pipes are equally as hot but none of them are cool to the touch either.
Can't wait to take it around the block tomorrow.
I also checked the compression on cold engine and got 130- 145.
But I guess that should be rechecked as choke lever was not functioning properly.
Next I'll do warm engine compression but I don't expect it to be more than 5% higher.
Engine did not run in well over 5 years so I think that once i start riding it and rings loosen up that the compression will be higher.
Next is brake overhaul followed by fork seals, rear shock and tires!
Thanks once again to all!

[NobleHops]

Well, who knows, knows! Thanks Steve and Dave for the tip!
I started taking things apart and noticed that cable on choke lever is loose!
The plate that pinches cable housing is lose and of course, choke was still on.
I attached it and made sure choke mechanism on the carbs is moving as it should, cleaned my plugs and now it's running on all six! Not all pipes are equally as hot but none of them are cool to the touch either.
Can't wait to take it around the block tomorrow.
I also checked the compression on cold engine and got 130- 145.
But I guess that should be rechecked as choke lever was not functioning properly.
Next I'll do warm engine compression but I don't expect it to be more than 5% higher.
Engine did not run in well over 5 years so I think that once i start riding it and rings loosen up that the compression will be higher.
Next is brake overhaul followed by fork seals, rear shock and tires!
Thanks once again to all!

Fantastic!

You are running a fuel filter, right? Do I recall you cleaned the tank and strainer when you started?

The more mine runs, the better it runs. Bleeding those big single pot brakes and the splitter has driven many of us to drink, do a few searches on the subject before you get there, save a few cocktails.

Ditto the fork service, that subject comes up frequently re the oil level, springs, emulators. Lots of good info on those topics.