SuzukiSavage.com - Fuel petcock

Oldfeller--FSO

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Re: Fuel petcock
Reply #30 - 09/17/11 at 06:09:30

Too kind, huh .... sometimes I wonder about that "too kind" stuff.

Wuz I being too kind when I teased Verslagen about him being a virgin engine rolling test bed for an "early onset oil consumption" episode due to an impending future vac petcock fuel starvation failure?

And now I've teased you about your future first vac petcork episode when it sputters and dies on you in tight packed traffic .... and somebody runs a SUV up your rear fender because you suddenly slowed down in the middle of traffic.

It is all jest good ol' cranky/teasing unless it might actually happen in reality, in which case wuz it really being kind at all?

==================

Routy, in the name of all things sane and good, please don't go into heavy traffic and play traffic/chicken with your vac petcock once it starts acting up on you any at all whatsoever.

I implore you, don't put your body at risk over a "disputed opinion" because although I like to be right, I don't like to be right all THAT much !!!

Me being right and you being hurt -- that is a poor assed trade I'd never make intentionally.

In other words, don't you be doing this kinda stuff -- I'd rather be wrong, really I would.

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« Last Edit: 09/17/11 at 15:58:38 by Oldfeller--FSO »

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Routy

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Re: Fuel petcock
Reply #31 - 09/17/11 at 22:35:03

I doubt that you are 1/2 that serious about my well being.
Actually since this PC stuff started,....since I been involved anyway, you guys have been batting a very poor average as far as any fuel issues being cause by the vac PC,.....even if we include the vacuum line,...... even if we include a shortage of vacuum source. There has been a couple vac line issues, and a couple vac source issues, but even some of those were not thoroughly verified.

And in reality, any bike that will still do 85 to 90 mph, is not in any danger of not being able to accelerate out of trouble at 10 or 20 or even 50 mph.
There has been many posts of fuel problems at low speeds, sometimes even at idle, whether it be lack of throttle response, hesitations etc etc, but yet will run good at crusing and WOT speeds, and the problem gets blamed on to the vac PC. I don't think thats fair to those who lack the knowledge of how a fuel system really works.

I have been accused of.......what ?? Telling the truth ???
Tell me where I was ever dead wrong when I said the problem was not the PC or the vac line, or the source ! I have ended up right most times ! You guys are perdy smart, I'll be first to admit, but you're not smart enough to always be right ! If you notice, I am not always real quick to post an answer, not till I analyze it from several posts.
Why am I even bothering w/ all this ???
Why are you concerned about my well being, when you are not concerned about your own,......meaning I firmly believe that the vac PC is a saftey device, in more ways than one.
But yet when I posted the news story of a fellow rider nearly burning to death riding a bike that I'd bet a lot of money did not have a vac PC, nobody wanted to hear about it possibly being an issue.
Now what if a fellow rider here that you so quickly told to change out the PC,.....before you even really knew the detailed facts of the fuel problem, got into a wreck like the one in the news last nite, and really did burn to death,.......what would you be feeling like today Shocked

Lets pray that don't happen !

Hey, don't mean this a personal attack,......like was thrown on me by a couple here, only as a few thoughts from my point of view.
Keep up your good work,.....most you guys do a fine job !

What all did I say above ?? Your guess as good as mine Wink

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Rich
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Oldfeller--FSO

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Re: Fuel petcock
Reply #32 - 09/18/11 at 00:51:13

Routy, I'll talk with you more later. Until then, it might be best for us to hold off on the heavy petcock discussions that might be picked up on by a legal secretary doing Google searches/research for her lawyer boss.

Google does source crawl our site -- go punch in "vac petcock Savage" and see what you get.

I was surprised, to be sure. We are not the only ones seeing the vac petcock issues.

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« Last Edit: 09/18/11 at 08:05:20 by verslagen1 »

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Routy Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 2280 Winston Oregon Gender:	Re: Fuel petcock Reply #33 - 09/18/11 at 07:46:46 You got it.
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Re: Fuel petcock
Reply #34 - 09/22/11 at 18:04:43

Hate to interrupt you guys, but I just finished the petcock swap on my bike. The problem was pretty classic -- the bike felt like it was ready to switch to reserve, but still stumbled on reserve. Ran OK on prime, so I did the swap.

It went just fine, only now I've got to re-check how far I can go before, and after, I hit reserve. Maybe I'll bring along a spare 1/2 gallon and do a fuel check ride. Hey, the weekend is coming up! Cool

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Every difference of opinion is not a difference of principle. Thomas Jefferson

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Bubba Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 956 Denver, CO Gender:	Re: Fuel petcock Reply #35 - 09/23/11 at 08:09:43 problem solved...hooray!
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Re: Fuel petcock
Reply #36 - 09/24/11 at 06:29:10

I just replaced my stock petcock with a raptor. I noticed the idle went up about 200 rpm. To me that means the vacuum draw to operate the stock pc was causing some loss of efficiency. So by extrapolation I might get a little better mileage? Undecided

BTW the reason I changed it was because I found it very difficult to turn the stock one due to arthritis in my hands.

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Re: Fuel petcock
Reply #37 - 09/24/11 at 07:00:22

arteacher wrote on 09/24/11 at 06:29:10:

I just replaced my stock petcock with a raptor. I noticed the idle went up about 200 rpm. To me that means the vacuum draw to operate the stock pc was causing some loss of efficiency. So by extrapolation I might get a little better mileage? Undecided

BTW the reason I changed it was because I found it very difficult to turn the stock one due to arthritis in my hands.

Something is definently strange.
The fact is, it doesn't consume any vacuum to operate a vacuum petcock.
If it was consuming vacuum, it had a vacuum leak,.....plain and simple. And the leak was very likely not coming thru the PC itself, or you would have had more problems.
But what is strange, is that if you had a vacuum leak,.....or in the case of consuming vacuum, it would not have been a quality idle, and most times the idle speed will slow, and become smoother when a vacuum leak is stopped.

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arteacher

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Re: Fuel petcock
Reply #38 - 09/24/11 at 07:58:08

"The fact is, it doesn't consume any vacuum to operate a vacuum petcock."
Some how energy is used to pull the spring in the petcock and the rubber vac line acts like a spring as well. This is what I meant by "using" vacuum. That energy is now available some where else.
Simple enough to verify- set your pc to prime, pull the vac line off the carb and cover the nipple on the carb with your thumb. Does your idle increase?
Years ago I installed an aftermarket cruise control on a Land Cruiser. I found that it would slow down while going up even gentle hills. The problem was that there was not enough vacuum generated by the engine to keep the diaphragm open in the cc actuator. (the vac line also ran the power brakes). The solution was to make a vacuum reservoir. I took one out of an old Volvo (everything was run with vacuum on old Volvo's) and put it on the vacuum line with a check valve at each end. Worked a charm.
That "savings" in vacuum when using the Raptor has to benefit something. Unfortunately I don't know enough about carbs to figure out exactly what. Huh

"and most times the idle speed will slow, and become smoother when a vacuum leak (use) is stopped."
Doesn't this kind of prove my point?

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Re: Fuel petcock
Reply #39 - 09/24/11 at 08:36:16

...either way,... that Raptor is definitely easier to turn, and it'll be still be easy 3 years from now...
Easier to remove the tank, too... Wink

...

I don't know why the idle went up either... a fixed leak would do as Routy said,... I don't know about the vac energy change... my car does drop in idle when I apply the brakes at a light, and it's in neutral...
...maybe it's just excited about getting the new Raptor...
Grin

...

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Ludicrous Speed !... ... Huh

...

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arteacher Serious Thumper Offline Ride as if your naked and invisable! Posts: 2581 London ontario Gender:	Re: Fuel petcock Reply #40 - 09/24/11 at 11:00:12 It probably drops rpm when you put the brakes on because of the increased load on the alternator.
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Serowbot YaBB Moderator ModSquad Offline OK.... so what's the speed of dark? Posts: 28649 Tucson Az Gender:	Re: Fuel petcock Reply #41 - 09/24/11 at 11:16:22 Hmmm,... maybe some LED tailights would be good... ...
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Re: Fuel petcock
Reply #42 - 09/24/11 at 18:31:49

I hate to be picky, but, hey,.. it is Saturday night,... and this stuff is fun to chat about! Grin

This statement is true: "The fact is, it doesn't consume any vacuum to operate a vacuum petcock." If there are no leaks, the vacuum applies a small amount of force to move the diaphragm/valve/spring/whatever,.. and no more vacuum activity takes place,.. simply a static force doing no work, and, therefore, using no energy.

This statement is technically incorrect: "Some how energy is used to pull the spring in the petcock and the rubber vac line acts like a spring as well. This is what I meant by "using" vacuum. That energy is now available some where else." It is a force that moves the stuff in the vacuum petcock, not energy. There is no energy gained or lost when the vacuum petcock is opened or closed by vacuum. There is no energy freed up to be used somewhere else.

If the vacuum operated systems put such a huge load on the vacuum source so that there is not enough vacuum FORCE available, then you have some other issues to address, but there is no ENERGY being transferred through the vacuum line, since we don't have things like vacuum-operated windshield wipers as installed on my Dad's 54 Chevy.

Now, what does all this have to do with this thread?
-- If the bike runs better when the vacuum lines are plugged up and a Raptor petcock is installed, it is because vacuum leaks were eliminated, and/or constrictions in the petcock were removed.
-- If the bike runs better when a new vacuum-operated petcock is installed and the vacuum lines are connected properly (meaning leak-free), it runs better for exactly the same reasons.

Either way, if you get rid of the malfunctioning parts, and install good parts (Raptor or stock), you will get an adequate fuel flow to the carb. Either way, there is no energy being used or saved, vacuum-wise.

I love this stuff!

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Serowbot YaBB Moderator ModSquad Offline OK.... so what's the speed of dark? Posts: 28649 Tucson Az Gender:	Re: Fuel petcock Reply #43 - 09/24/11 at 18:55:06 Ahh haa!,... so I was right!... The bike is just excited about getting a new petcock... ... aren't they cute when they get a new toy.... ...
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verslagen1

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Re: Fuel petcock
Reply #44 - 09/24/11 at 19:00:38

Gyrobob wrote on 09/24/11 at 18:31:49:

I hate to be picky, but, hey,.. it is Saturday night,... and this stuff is fun to chat about! Grin

This statement is true: "The fact is, it doesn't consume any vacuum to operate a vacuum petcock." If there are no leaks, the vacuum applies a small amount of force to move the diaphragm/valve/spring/whatever,.. and no more vacuum activity takes place,.. simply a static force doing no work, and, therefore, using no energy.

This statement is technically incorrect: "Some how energy is used to pull the spring in the petcock and the rubber vac line acts like a spring as well. This is what I meant by "using" vacuum. That energy is now available some where else." It is a force that moves the stuff in the vacuum petcock, not energy. There is no energy gained or lost when the vacuum petcock is opened or closed by vacuum. There is no energy freed up to be used somewhere else.

Technically, you're incorrect. The work done is very small. So the energy used is very small.

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