The International CBX Owners Association

Hello Chaps, I need some advise please (cbx 1980A).
Can I remove the auto valve (between fuel tank and carbs) and replace it
with a fuel hose with a “T” piece?.
If I can, what happens to the small hose that went to carb 3.

Edd

Edd,

Yes, you can remove the vacuum fuel valve and run a direct fuel line to both fuel intakes on left / right banks of carbs - via a T piece as you say.

The hose from carb three is the vacuum that opens the fuel valve when the engine is running. Just remove the fitting that screws into carb 3, and replace with a blanking screw as for the other 5 carbs.

Of course, if you do remove the valve to avoid the risk of hydrolock make sure you always turn off the fuel at the petcock, and leave the bike on the centre stand.

Paul.

Many thanks for the guidance Paul, On that note regarding hydro-locking,
when I change to new hoses and "T" piece, When I've finished riding for the day,
would It serve any purpose to turn off the fuel tap and let it run until until it splutters to a stop?

Long time CBX rider J.R. is an advocate of that proceedure.
About a kilometer from home turn off the gas and then run the carbs dry in the garage if you have to. It also lessens the chance of any ethanol deposits clogging up your carbs.
I just turn off the petcock every time no matter what bike i am on.

Edd,

Running the carbs dry is good practice as far as ensuring the jets don't get gummed up from standing in (stale) fuel. I always do it if am not going to use the bike for a day or two.

Paul

Two different things here guys. First, the risk of hydrolock is there whether you run the carbs dry or not, if you are not religious about leaving the petcock in the off position. The reason for draining the carbs is to aid in cold starting the next time, which will improve by removing the vacuum valve, usually. So, if it is not still clear - TURN OFF THE PETCOCK when the bike is sitting.

Dave

I am a little confused here, Dave. When you run the carbs dry, you have the petcock closed when you park the bike. No chance for a hydrolock.

daves79x wrote:Two different things here guys. First, the risk of hydrolock is there whether you run the carbs dry or not, if you are not religious about leaving the petcock in the off position.

And then, how is this going to help cold start the next time. The carbs are completely dry, which is usually the reason for a hard start.

daves79x wrote:The reason for draining the carbs is to aid in cold starting the next time,

short-edd wrote:Hello Chaps, I need some advise please (cbx 1980A).
Can I remove the auto valve (between fuel tank and carbs) and replace it
with a fuel hose with a “T” piece?.
If I can, what happens to the small hose that went to carb 3.

Edd

Put a little gasket sealer onto an appropriate size short bolt and stick it into the end of the hose. Done. Then, learn a new habit of turning the petcock to 'OFF' any time you park the bike -- even to go for a cup of coffee. (You will never go farther than a mile without 'remembering' to turn it on.) Personally, if my bike is going to sit longer than 2 days, I drain the carbs. Only requires a long thin screwdriver and a couple minutes.

The whole point of making these easier to start IS to begin with dry bowls - no stale gas to try to fire. Just turn on the petcock (no vacuum valve) a bit before starting and let the bowls fill with fresh gas. The bike will start instantly. We've been over this countless times.

Dave

Well, I didn't think we were talking about hard starting after parking the bike for a month or two......and there could be stale gas in the fuel tank after a longer sit. So you would have to drain that too.
The procedure they described to run the carbs dry after a ride by closing the petcock before you get home, was obviously something someone recommends to do every time.

All I'll say is that my experiences and thoughts on all this are well-documented in many other threads.

Dave

EMS wrote:<edited>The procedure they described to run the carbs dry after a ride by closing the petcock before you get home, was obviously something someone recommends to do every time.

I am not a fan of this method. It leaves fuel in the float bowls, which is bad enough, but also in the jets. The correct way is to treat the fuel with a stabilizer, run two or more miles to get it into the circuits, then drain the float bowls completely.

I am with you, Mike. When you want to store the bike.
But that procedure they describe is during usual operation, after every ride, at the end, they run the bike until it dies from fuel starvation.
Next day, they have to (try to) start the bike on empty carbs.
That's the point.

Ahh. I missed that point. Jumping in without having all the facts, my usual pattern.....

a couple of weeks ago I came across a '81 parts bike that had an enormous hole in the crankcase below #1, first time I've seen that close up...that would make me cry if it was my Z...I always turn off fuel, always keep it on the center stand and six individual drains for carbs.


but as to Dave's method for long storage which I follow worked well, instant start. You just need to allow a little time for the float bowls to fill.

as for draining every day or if the bike sits for two weeks, I never do... full choke, turn on fuel, hit start and it fires right up. I may be building up deposits in the carbs by doing it this way but for now I haven't had any problems. What I find most likely to cause any starting hesitation is the air temp.