cvk34 vulcan 500 carb problem

Erm?

 

Name your exception. I know you're going to.

Vacuum doesn't lift an airplane's wing, it's the differential pressure
between top and bottom, and the reaction force of the downwash.

Some classic lab demonstrations:

Take a rubber suction cup and wet it for a good seal and stick it onto
a piece of glass.

You can pick the glass up with the suction cup because of the weight of
the atmosphere,
over a ton per square foot, pushing the outside of the rubber cup
against the glass, not because of vacuum inside the cup.

Place a piece of cardboard over the top of a full glass of water and
quickly invert the glass, while holding the cardboard against the top
of the glass. After a certain amount of water leaks out, a low pressure
empty area will form in the bottom of the glass, which is now on top,
and you can take your hand off the cardboard and atmospheric pressure
(over a ton per square foot), will hold the cardboard against the rim
of the glass.

A physicist once took a pair of metal hemispheres and placed the lips
of the hemispheres together and evacuated all the air from the
hemispheres which were now held together only by the weight of the
earth's atmosphere (over a ton per square foot).

Two horse pulling on the hemispheres in opposite directions could not
separate them...

Take a wooden spool from your wife's sewing box. Push a pin through a
small piece of cardboard and put the pin into one end of the spool and
blow air through the other end.
The harder you blow, the harder the weight of the atmosphere (over a
ton per square foot) will push the cardboard against the spool.

 

No vacuum, no effect of air pressure.

Can't have one without t'other.

Action and reaction (after a fashion). So you can as validly say that
the vacuum is holding them together as you can say that air pressure is.

Got any more thoughts about car-type bike clutches, while we're at it?

Look, let's be honest here. You know a lot. There are also some amazing
gaps in your knowledge and a lot of perceived wisdom and bias
masquerading as fact (like when you said chain oilers are a waste of
time).

However, as I've said many times, if you say something on Usenet that is
manifest bollocks, and get called out over it, it's a really good idea
to shrug, fess up, say "I goofed", or similar, and everyone moves on.

Moving goalposts, inventing "reasons" and "you're saying xyz, then?"
excuses makes you look an imbecile and, and puts you in the same
category....

....as Hoyt McKagen, who was another bod who knew a lot but couldn't
remove the blinkers when necessary.

 

Bollocks.

 

OK, let's have the reasoning. Without a vacuum, the air pressure would
not hold them together. Yes, the air pressure is pressing the parts
together, but without the vacuum....

und so weiter, und so weiter, ad nauseam.

The two are inseparable. Yin and yang, equal and opposite.

It's semantics anyway - people talk about vacuum gauges, vacuum taps,
vacuum cleaners and vacuum forming, for a pretty good reason.

Now, got any more thoughts on car-type dry clutches?

 

B-12 schreef:

Yes, bollocks.

Vacuum does not suck, The differential pressure pushes.
At least that is what I was tought when I studied aircraft design.
But it doesn't really matter what you say, as long as the result is
the same.
It sometimes is easier to calculate how much (mass/second) air is
pushed (accelerated) downwards by a wing than to calculate
the pressure at each square mm of the upper (curved) side
and the lower (curved) side of a wing and multiply that by the
surfaces of upper and lower wing side, corrected for the angle
of each square mm to the vertical, in order to get how much lift
this wing gives.
Done properly, both calculations give the same result.
So in effect you also may say that acceleration of air downwards
is what the wing tilts upwards. There is action=reaction for you.



I used to read this NG regularly many years ago (at work), and
only recently rediscovered it. What has happened to the famous
Hoyt?

Rob.

 

This is more or less what I've said in my posting made a couple of
minutes ago. Yes, the air pressure pushes things together, no it
wouldn't without a vacuum, yes, it's semantics.

As for Hoyt, he dropped off the twig a year or so back.

 

Newtownian physics is about force and mass and time. Pressure is a
force. Vacuum is the opposite of that force only because the force has
been removed.

Back to my nap...

 

Hence my qualification "(after a fashion)." Which, I note, you have
deliberately chosen to ignore.

Look, I'm not disagreeing it's about pressure differential. Merely that
it is so much easier to go along with everyday terminology. See my brief
explanation of how a Kawasaki 550 fuel tap works, elsewhere.

There is just no need to complicate things. KISS. I mean, wlesewhere
some bloke is asking for a simple home job to improve his XT350 front
forks and you give him 5000 words of tech bollocks. Why?

 

This will not assist the original poster who is probably looking for a cure
not quotations from engineering reference books. If you understand the
principle, the terms are irrelevant.

If not, the same applies in this case.

I defer

 

GaZ wrote:

Precisely. "Pressure differential" was the phrase I was struggling for
(thanks to the bod who supplied it).

If someone wants a fix, they want a fix and not reams of irrelevance.

 

Don't forget that you're the one who directed the thread off into these
thorny bushes with your diaphragm that magically detaches and
reassembles itself to the slide.

What the heck year and model had diaphragms that weren't securely
fastened to the slide, some 1968 Honda CB350?

The OP has a more modern machine than that, and the diaphragm will be
fastened to the slide with a plastic ring.

 

Or bonded to it and not separable. Never seen a replaceable diaphragm
on any Jap bike, although IIRC BMW Bing diaphragms are available as
separate units.

The place for replacement diaphragms, if anyone is ever interested, is
NRP Carburettors, here in the UK. Send them your old diaphragm/slide
assemblies, and in a week or less they attach new diaphragms and post
them back (might take a few days longer to the US).

Incredibly good product, costs a third to a half the price of OE, and
excellent service.

 

What the heck year and model had diaphragms that weren't securely


1996 Virago, close relitive of the bike in question.

The diaphragm is attached to the slide by 'sandwiching' the centre cut out
rim between a cylindrical sleeve and the inside of the slide. When the
diaphragm lifts the sleeve, the slide does lift with it. When the diaphragm
returns under the spring force, it re-inserts itself and looks ok to a
casual inspection. It was only spotted by looking down the carb while the
bike was running.

 

The original equipment carbs on my GSXR have that cylindrical sleeve
you mentioned.

It's made of ABS plastic, like the slides, and there are four plastic
pins extending from the cylinder, through holes in the slide, and the
ends of the pins were heat formed into plastic "rivet heads" so the
parts couldn't come apart without breaking something.

I would think that Hitachi (or whoever made your Virago's carbs would
at least superglue the cylinder into the slide.

 

The bike was almost 4 years old when I got it, so it is possible that the
diaphragms were replaced by an aftermarket 'fix'.



I know it is not a likely problem, but I thought I would mention it as it
took me a while to find as I had never seen or read of it before.

 

Perhaps this will open a whole new dialogue into "Loose Diaphragm
Syndrome" and how it defeats the aspirations of new riders. ;-)

Oddball mechanical or electrical problems become grist for the
experienced mechanic to
talk about---or even start a small business dealing with the rare
problem.

One oldtimer at the RC airfield had a problem with fuel starvation on
one of his ARF's.

So he started his own cottage industry right there on the picnic table
at the RC field.

He would tell newbie RC pilots that the fuel starvation problem was
very common, and he would charge them $20 to cut the top of the
fuselage off their brand new $500 ARFand convert it into a removable
fuel tank access hatch...

 

Without intending to drag off subject again, I am hardly a new rider. My
first matchless in 1962 was followed by around 60 other assorted specimens,
and 4 years of my apprenticeship was spent in a Honda dealer.

But I am of the opinion that no matter how oblique a cause is, it is easier
to find if others have mentioned it.

And. as in the old saying, in the land of the blind the one eyed man is
King.

 

As I recall, it was H. G. Wells who exploded that particular myth. His
protagonist went into the Valley of the Blind in South America, and the
peasants poked both his eyes out in order to make him "normal".

 

Quite the conversation guys. Sorry I havent posted in so long, to be
honest I am just about fed up with this &*$&ing bike. I have to store
it at my parent's for the winter, except they live 2 hours away so time
is ticking before the snow starts flying. I guess Im just so fed up I
dont want to bother with it anymore.

But today I went at it again.

So, GaZ, you were mentioning that the slide was seperate from the
diaphram?

Okay. That's not it though, the diaphrams seemto be intact and seated
properly. One was a bit off, but popping it into itself let me seat it
perfectly.

The problem remains; the throttle cuts out the engine when it is
applied.

I once again hauled it apart and cleaned the three little holes goingto
the pilot circuit. To whomever asked if I accidentally put the pilot
and main into the wrong areas, I didn't I've changed the plugs again
to be sure they arent the culprit; someone on anther forum said, while
the possibility was quite remote, that the new plugs I put in were from
a bad batch.

So I dont know what to tell you guys. I dont know why a) something
would be this plugged up if it worked before I cleaned it, I understand
some sediment might have came loose but this is ridiculous and b) why
both carbs are affected. As someone else said, you would think that one
cylinder would be working correctly.

Which leaves me to believe that I have overlooked something stupid, and
this stupid thing is affecting both carbs. I've double checked the
parts diagram eleventy billion times. And I did make sure I put the
needle jet in the correct way. My needles are not bent at all, they are
perfectly straight. They are also in the right way

I'm going to play with the floats tonight to try to get them spot on; I
personally dont think thats the problem because I didnt touch them when
it was disassembled but who knows,I may have bent them both a little
with all this man handling.

Believe me your continued suggestions, no matter how stupid they are,
are well appreciated. As I've said, I figure its something REALLY
stupid and something that is mutual to both carbs that is keeping
these things from working right.

Thank you so much.