Build Thread...Special to Cafe Bike

[weekendrider]

RG did you ever just take the float valve out and try it that way? If it doesn't shut off why have it?
Bob can make his own decisions. I have never thought much of posses.
And I will continue to adjust and set my float heights by the mfg.s guidelines knowing that they intend the fuel to shut off a certain point.
The petcock isolates the fuel to the tank.
The float valve isolates the fuel in the carb bowl.
Simple concept for me.

 

[YamadudeXS650C]

I am miles away from being any sort of expert or guru, but it is my understanding that the float needle valve does the job of providing a reservoir of fuel for the carb. Just enough fuel. Not too little (in consideration of bursts of intense acceleration), and not too much. But it is not a shut-off valve.

 

[Bob Kelly III]

I am miles away from being any sort of expert or guru, but it is my understanding that the float needle valve does the job of providing a reservoir of fuel for the carb. Just enough fuel. Not too little (in consideration of bursts of intense acceleration), and not too much. But it is not a shut-off valve.

but it IS a shut off valve ! ...... or you would have gas running all over the floor Dude ! your wording is wrong is all
it's Not intended to be a Permanent all pervasive shut off valve NO I agree with that, but it has to shut off the fuel completely at some point or you loose fuel ! I know you know that..... so quit saying it's not a shut off valve ! it has to be ..... LOL
or when you turn on the gas it would immediately start leaking.....
either that or define what you mean by a "shut-off valve" <grin>
.....
Bob.......

 

[YamadudeXS650C]

but it IS a shut off valve ! ...... or you would have gas running all over the floor Dude ! your wording is wrong is all
it's Not intended to be a Permanent all pervasive shut off valve NO I agree with that, but it has to shut off the fuel completely at some point or you loose fuel ! I know you know that..... so quit saying it's not a shut off valve ! it has to be ..... LOL
or when you turn on the gas it would immediately start leaking.....
either that or define what you mean by a "shut-off valve" <grin>
.....
Bob.......

Yup, it does perform a gate-keeping function while the engine is running. So, we are in agreement.
But, it is not a ........................I won't say it again, I promise.

 

[YamadudeXS650C]

Kinda seems like The Controversy has been unearthed. Damn, am I to blame ?

 

[Bob Kelly III]

And while it's sitting doing nothing on the side stand with the fuel petcock left on...... it's expected to shut off the gas then too !
.... But certainly it's MAIN function is a metering device to allow a certain amount of fuel into the bowl this much and no more and keep that level..... As 2M said in another thread I am amazed they work as good as they do because the fuel is anything but level with all the vibration in them.... it's not level at all.....
I saw a bike run one time that had see through float bowls on it, i think it was a Honda 750-4 and the fuel level was not definable with it running !..... it was splashing all over the place ! bubbles of air all through the gas at idle ! and yet the carbs have emulsifier tubes just for that purpose ! LOL......I bet the engines would run just fine without emulsifier tubes in them at all because of the constant adjation !
.....
..... What controversy ? you're all saying the same thing ! just wording it wrong is all ! LOL and yes don't say that word again ! LOL

....
Bob.........

 

[mrtwowheel]

The fuel delivery system, tank, fuel line, petcock, filter, better deliver more fuel than the carburetors will ever need or the bike will run LIKE CRAP. The float valves better shut down the fuel when they are pressed against the seats or the carbs will overflow.

Living with the other scenario we should all live in fear of letting our bikes idle while the carbs are over filled.

NONE of my bikes NEED their petcocks shut off while sitting, if they did, then there is something wrong with the system.

Scott

 

[650Skull]

Not to add to contraversy, this is a discussion on the true value and efficency of a Float valve.........

look up what the definition of the word "Valve"

Float Valve..........Look up what that means.......

Carb float valves work in the same way as all float valves do........When the level of fluid gets to a preordained level the float has triggered a valve to stop any more fluid from entertaining that chamber............How can you have a float height if the fluid can't be stopped...........

Any biker with carb experiance knows not to rely on these valves.........why, because floats can get stuck...........this leaves the float valve open and if the petcock is not turned off then you have fuel all over............Not the valves fault......it couldn't do it's job and shut the fuel off

Petcocks are 100% guaranteed to stop fuel from entering the carbs....................

Your petcock might be letting gas through (like it has failed). The float needles are not actually designed to FULLY shut off the gas, am I correct?

Any old timer will say yes to this question because it will to make sure you remember to turn the fuel off at the tank. Recommended practice.

Yamadude quote:
" The float needles, as I mentioned, are not expected to fullly shut off the gas."

Absolutely correct. That is why the petcock (or peacock ), must be 100% shut off capable..

Don't agree as per above.........agree on "turn off the Petcock"

 

[YamadudeXS650C]

Not to add to contraversy, this is a discussion on the true value and efficency of a Float valve.........

look up what the definition of the word "Valve"

Float Valve..........Look up what that means.......

Carb float valves work in the same way as all float valves do........When the level of fluid gets to a preordained level the float has triggered a valve to stop any more fluid from entertaining that chamber............How can you have a float height if the fluid can't be stopped...........

Any biker with carb experiance knows not to rely on these valves.........why, because floats can get stuck...........this leaves the float valve open and if the petcock is not turned off then you have fuel all over............Not the valves fault......it couldn't do it's job and shut the fuel off

Petcocks are 100% guaranteed to stop fuel from entering the carbs....................


Any old timer will say yes to this question because it will to make sure you remember to turn the fuel off at the tank. Recommended practice.



Don't agree as per above.........agree on "turn off the Petcock"

Your points are well stated, Skull.

In my own words, stated more accurately than I did above, the float valve cannot be expected to reliably / consistently shut the fuel off. Thus, it should not be regarded as being a shut off valve. (Damn, I said it, again). Therefore, we shut off our petcock when we stop the bike.

 

[mrtwowheel]

Clean fuel tank, fuel filters in place, floats checked for leaks, periodic maintenance with Seafoam, TC-W3 or Stabil, my float valves don't leak, and the floats don't stick.

100% petcock shutoff? That's only achieved by regular and preventative maintenance too.

Scott

 

[weekendrider]

Finally, based on Peanut's experience in trying to get to his MOT, I'll try just giving the leaking carb a gentle little cuff with a piece of wood. It was JUST rebuilt by a really good guy who knows his stuff so I'm sure it must just be a little speck of dirt.

If you truly believe the float valves always pass gas(or don't shut off whichever way you care to phrase it) why would you whack them?

 

[mrtwowheel]

If Peanut would have stored his bike with a full tank of gas, Stabil or TC-W3 in the carbs or maybe not, and the petcock open, he wouldn't have had to whack 'em.

Scott

 

[MaxPete]

Wow guys! I went out for the evening and a whole debate happened!

In my view, float bowl needle valves should shut off - but in my experience, sometimes they don't. I agree that is what petcocks are for, aside from providing the reserve function, which on a bike with no fuel gauge, is pretty handy. I have normally shut them off when parking my petcock equipped bikes - but I must admit that have occasionally forgotten to do so.

My '07 Honda ST1300 doesn't have a manual petcock - or even a visible petcock of any type. However, I have never seen anyone on the ST Owners forum complain about a fuel leak problem, so I guess it's ok.

Unfortunately, the older XS650s vacuum petcocks do seem to cause problems occasionally, so my Cafe bike will have manual petcocks, just like my '76 Standard.

Anyhow - interesting topic!

Pete

 

[mrtwowheel]

Careful MaxPete, you could start a debate about the vacuum petcocks (SOS, son of satan).

Scott

 

[MaxPete]

Shoot Scott, I'd rather talk about oil or tires, or chain lube or perhaps I'd rather have my head stapled to the floor

Pete

 

[mrtwowheel]

"As soon as I stick this red hot poker up my ass, I'm gonna chop my dick off,", George Carlin.

Topic, when I install a cleaned, empty carb, I expect the float to stick, and I have a screwdriver handle or piece of wood ready, to whack it.

Scott

 

[650Skull]

Your points are well stated, Skull.

In my own words, stated more accurately than I did above, the float valve cannot be expected to reliably / consistently shut the fuel off. Thus, it should not be regarded as being a shut off valve. (Damn, I said it, again). Therefore, we shut off our petcock when we stop the bike.

Yes......

 

[Bob Kelly III]

that's probably the Clearest explanation yet Dude !!!! Very good !
.....( even if you did say it again !) LOL
Bob........

 

[Bob Kelly III]

Depending on the bike there are bikes I've had that I turned the gas on once a day and off at night no mater what I did....
and others that I wouldn't do that ever ! .....
it's Not mandatory but it is an accepted practice to turn off the gas when parked ! also a good theft deterrent
I remember reading about a guy who got off his bike and left it parked and was about 200 ft away at a bar b q.. when some Kid hops on his bike fires it up and rides off and he's running after him screaming obscenities..... the bike sputters and dies ( because he turned off the gas) and the kid hops off and runs for his life, the guy catches him and beats him to a pulp and He is arrested and his bike impounded ..... it cost the poor guy over a thousand bucks to get his bike back , after 3 or 4 days in jail , when the Judge heard his story the Judge threw it out and didn't allow any charges to be pressed... but it still shouldn't have went down that way.... wouldn't have back in the 1950's but today is another story !
the Kid didn't want to press charges it was the money grubbing lawyer that did !
.....anyway......so much for having a Keyless ignition on your chopper eh ?
.....
Bob.........

 

[650Skull]

that's probably the Clearest explanation yet Dude !!!! Very good !
.....( even if you did say it again !) LOL
Bob........

Just for you i had to say it again................And where was the first time.........

Yamadude..........It is a Stop valve