Fuel petcock...is it really needed?
Men...@hotmail.com
last weekend I decided to experiment with just leaving the damned
thing on all the time during this week to see what happens. Guess what?
Nothing happened except my bike (XR200) started on the first kick every
day this week.
My four stroke riding lawnmower does not have a petcock. My 2 stroke
chainsaw and weedeaters do not have petcocks. What gives? Why do
motorcycles have these things? It's just one more thing to clog up.
Correct me if I'm wrong, but the way I understand how a carb float works
is that as fuel is removed from the bowl, the needle opens and it is
replaced by fresh fuel. In the case of a not running dirt bike, this
would happen due to evaporation. It would seem to me that keeping the
needle seal wet with fuel (especially with 2 strokes) would be a good
thing.
Perhaps at some point in the past fuel ran past the float bowl into the
engine and screwed stuff up?
If nobody can convince me otherwise, I'm going to remove my petcock and
bolt in a deal from a lawnmower gas tank. I've had it with worrying
about it and almost crashing when the engine dies because I spoded out.
-Mental
ps...is this the most times you've seen the word "petcock" in the same
post or what? ;-) heheee
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
DirtDoggie
>motorcycles have these things? It's just one more thing to clog up.
Lets see, I’m not an expert but let’s try it.
I turn my petcock off to pull my fuel tank off the bike during maintenance.
Which by the way is at least once a week. I can then set the tank (with gas in
it) just about anywhere without having to drain it.
I also turn it off while I am trailering my bikes so that while they are
bouncing up and down their not draining their fuel contents all over my
enclosed or open trailer.
It’s also convenient to shut off the flow while going through the process of
re-jetting a bike at track side.
I’m sure there’s more let’s think about it.......
BTW: I can’t remember the last time my fuel petcock got clogged up.
DD
DirtDoggie's Triple Crown ------------------------------
99 YZ400F "Mighty Moe"
97 YZ 250 "Big Blue"
99 YZ125 "Dave's Dream"
xx...@webtv.net
eric...@my-deja.com
OK...There is some utility in these cases but I'm still not sure it
outweighs the aggravation. Other small engines I've worked on get a
pair of hemostats clipped on the fuel line when removing the fuel tank.
I've noticed that most dirt bikers are adamant about shutting of their
petcock's even when parking for just a few minutes. Why?
Could there be over-arching psycho-social forces at work here? ;-)
-Mental
fas...@my-deja.com
eric...@my-deja.com wrote:
> In article <19990610015159...@ng-fw1.aol.com>,
> dirtd...@aol.com (DirtDoggie) wrote:
> > >Why do
> > >motorcycles have these things? It's just one more thing to clog
up.
Snip Snip
>
> OK...There is some utility in these cases but I'm still not sure it
> outweighs the aggravation. Other small engines I've worked on get a
> pair of hemostats clipped on the fuel line when removing the fuel
tank.
> I've noticed that most dirt bikers are adamant about shutting of
their
> petcock's even when parking for just a few minutes. Why?
>
> Could there be over-arching psycho-social forces at work here? ;-)
>
> -Mental
>
> Sent via Deja.com http://www.deja.com/
> Share what you know. Learn what you don't.
>
I am adamant about turning the petcock off from having to deal with
bikes with Bings on them as in the 70's when Bings then were
slobber-matics. Not the carbs of today. If you ever made the mistake
back in the 70's to trailer a bike with a Bing on it and forget to turn
off the petcock, then you found out real quick why you should have
turned it off. KTM didn't put a removable plug in the bottom of the
crank area for looks. It was real nice for draining a crankcase full
of gas. Or water. Also there was nothing funny about getting to a
reset and not turning your petcock off and taking a leak and upon
coming back seeing the gas dibbling out of the overflow tubes,
especially when you needed every ounce of gas to to get to the gas stop.
I was taught to do this thing of turning the gas off early on. Maybe
bikes today don't need it. It's a habit with me.
Freddie
-------------------------------------------------------------
I know the perfect woman for
me exists, but the judge was very
specific in his restraining order.
Cameron Lemon
petcock attached. I only turn mine off when doing maintenance, aside from
this, I always leave it on. I turned it off once when trailering the bike,
and the float tab got bent. It was explained to me as there was no fuel in
the bowl, there was nothing from keeping the float from moving freely, so it
flopped around for over 1.5hrs while being trailered down rough roads. Not
sure if this was the cause or not, but makes some sense.
<snip>
Peter Patton
time the gas in your bowl cam damage your floats or even saturate them. I always
trun mine off after riding for several reasons--the one above (probably a non
issue); so the oil from the WHOLE tank doesn't settle to the bottom (carb) and
risk plug fowling on startup; so I am not putting undue pressure (gravity of the
gas weight) on my floats. I don't know the truths behind these, they are just
things I've heard over the years. Actually, unless you draing your bowl, there
is a carburetor full of gas when you turn off your petcock.
Peter
Cameron Lemon wrote:
--
http://people.mn.mediaone.net/motoppl/public_html/index.html
mot...@mn.mediaone.net
Motocross Rules!!!
Peter 3 # 524
Peter # 739
Peter Patton
(My own terminology) What I mean is that when the vehichle is turned off it
is the same as manually turning off your petcock, exept it's done
automatically.
Peter
Men...@Hotmail.com wrote:
> Having done the spodely forget-to-turn-the-petcock-on during my ride
> last weekend I decided to experiment with just leaving the damned
> thing on all the time during this week to see what happens. Guess what?
> Nothing happened except my bike (XR200) started on the first kick every
> day this week.
>
> My four stroke riding lawnmower does not have a petcock. My 2 stroke
> chainsaw and weedeaters do not have petcocks. What gives? Why do
> motorcycles have these things? It's just one more thing to clog up.
>
> Correct me if I'm wrong, but the way I understand how a carb float works
> is that as fuel is removed from the bowl, the needle opens and it is
> replaced by fresh fuel. In the case of a not running dirt bike, this
> would happen due to evaporation. It would seem to me that keeping the
> needle seal wet with fuel (especially with 2 strokes) would be a good
> thing.
>
> Perhaps at some point in the past fuel ran past the float bowl into the
> engine and screwed stuff up?
>
> If nobody can convince me otherwise, I'm going to remove my petcock and
> bolt in a deal from a lawnmower gas tank. I've had it with worrying
> about it and almost crashing when the engine dies because I spoded out.
>
> -Mental
>
> ps...is this the most times you've seen the word "petcock" in the same
> post or what? ;-) heheee
>
> Sent via Deja.com http://www.deja.com/
> Share what you know. Learn what you don't.
--
John
the floats didn't
I saw a bike spontaneous combust scary.....
my reason is the old bikes I had would leak into the cylinder and flood
the bike.
My xr600 I leave on most of the time
but trail 70's gas gets turned off before the key.
john
Josh Sheesley
want to drain your gas tank every time you take you carb out to
clean/service/re-jet it. Second, if you use your bike off-road then
there is that chance of crashing. Floats only work when the bike is
upright, and will dump your gas out all over the ground, or you if your
under the bike, if it lays on it's side for very long. So if you crash
and cannot pick your bike up for a period of time then you will have gas
pouring out of the over flows. Three, if you have a dual sport, then you
will probably have on/off/reserve. If you are 10 miles out and go to
reserve, then you need to get some more go juice. If you had no petcock
on your bike that is going to be a long walk/push. I'm sure that there
are many more reasons to leave the thing on there, but these should be
enough to convince you.
Josh {;-)>
99 KX250
dust...@my-deja.com
That way we, someday, may get to read the following type of posts:
Removed Gas Tank, Gas spilled everywhere...
Why does my motor not run, now that my bike burned up.
Laid bike over, gas went everywhere, garage caught on fire, damn bike
makers! who do I sue?
in other words:
Leave the petcock alone.
Put the tools back where they *belong*
David E. Wilson
Men...@Hotmail.com wrote:
> Perhaps at some point in the past fuel ran past the float bowl into the
> engine and screwed stuff up?
>
Yes, it can. I don't think that would be a good idea for all the reasons
mentioned. A important reason (but it's not common any more) that wasn't
mentioned is that, on a two stroke at least, the fuel can get into the
bottom end of the engine and cause a hydro lock above the piston when you
try to start the bike. It can actually bend the rod, just like getting a
lot of water in your motor and not taking the spark plug out etc prior to
kicking the bike over. I had this happen once...but it was back in about
1968. This will only happen if the float sticks for some reason or the
valve is going bad. Maybe now the rod are stronger and this can happen, but
I don't want ot find out. This is much less likely to happen to a four
stroke but I guess I wouldn't want a lot of gas draining down into a four
stroke engine either. I shut off all petcocks as soon as I'm done riding
the bike, no matter the type of carb or the type of bike. Of course I also
change air cleaners most every ride and do all the maintence on even trial
bike like I was getting them ready for a long distance race too.
Dave
Jim Hall
>I am adamant about turning the petcock off from having to deal with
>bikes with Bings on them as in the 70's when Bings then were
>slobber-matics. Not the carbs of today. If you ever made the mistake
>back in the 70's to trailer a bike with a Bing on it and forget to turn
>off the petcock, then you found out real quick why you should have
>turned it off. KTM didn't put a removable plug in the bottom of the
>crank area for looks. It was real nice for draining a crankcase full
>of gas. Or water. Also there was nothing funny about getting to a
>reset and not turning your petcock off and taking a leak and upon
>coming back seeing the gas dibbling out of the overflow tubes,
>especially when you needed every ounce of gas to to get to the gas stop.
>
>I was taught to do this thing of turning the gas off early on. Maybe
>bikes today don't need it. It's a habit with me.
>
>Freddie
Yeah, what he said. You haven't lived until you have had to deal with
an old Amal or Bing carburetor. Even old Mikunis, for that matter.
I also change jets.. a lot. I ride elevations that vary from sea level
to 8,000 feet. I could use hemostats or vice grips on the fuel line,
but the petcock works quite nicely, thank you.
I'm not religious about turning the gas off every time I park for a
few minutes, but I certainly turn it off before transporting.
But hey, if you want to treat your motorcycle line a lawn mower, who
am I to complain..... <g>.
>-------------------------------------------------------------
>
>I know the perfect woman for
>me exists, but the judge was very
>specific in his restraining order.
..... sputt......
Damn Freddie, did you get a new "Jokes for the John" book for your
birthday?
Jim Hall
380 EXC and others
turning Money into Noise...
Thank you Big Joe's Cycle; Plateau Engineering
Jay C
>My four stroke riding lawnmower does not have a petcock. My 2 stroke
>chainsaw and weedeaters do not have petcocks. What gives? Why do
>motorcycles have these things? It's just one more thing to clog up.
The needle valve is a metal on metal seal. Although it may be normally OK
to leave your petcock open for a while, I wouldn't take it off. A teeny
piece of debris can cause a needle-valve leak which can fill your cylinder
with gas and cause all sorts of problems. This may be more of an issue with
2-smokes however. I had this happen to my Yahama Virago 1100 once while it
was actually running (the Virago has no petcock because it uses a fuel pump
like a car) - killed the cylinder and blew blue/black smoke everywhere while
gas literally spewed out of the side of the motor - I thought I blew it up
for sure. Most importantly, you cannot lay any dirt bike on its side
without turning off the petcock or fuel will continuously pour out of the
carb o-flow tube. During trail-side maintenence or after a good biff,
turning the petcock off is manditory.
Jay
M. Williams
>
<snip>
>
> Laid bike over, gas went everywhere, garage caught on fire, damn bike
> makers! who do I sue?
I had a Royal Enfield burn up on my in college when a combination of a
stuck-open float needle and a backfire thru one of the carbs lit a fire
that escalated and took out the whole bike. If I'd just closed the
petcock when it was a tiny fire, it never would have gone too far.
But... for my $200 investment in that bike, I did get a great show!
Mike W
'96 XR400
Steven Eric Romer
Men...@Hotmail.com wrote:
<snip>
>
>If nobody can convince me otherwise, I'm going to remove my petcock and
>bolt in a deal from a lawnmower gas tank. I've had it with worrying
>about it and almost crashing when the engine dies because I spoded out.
>
>-Mental
>
>ps...is this the most times you've seen the word "petcock" in the same
>post or what? ;-) heheee
<snip>
You can use it to teach your bike good manners. I shut the gas off if
the bike is doing things I don't like. Be sure to tell the bike why
you are punishing it. I say "OK, I've had it with your two-wheeled
shenannigans!!--no gas for you! Time out!!" when I turn it off.
Doesn't happen that often on the dream cycle of course, but it is
effective--the bike quiets right down!
Steve A-#1 rider in the world
94 XR650L dream cycle
Steven Eric Romer
<snip>
> after a good biff,
>turning the petcock off is manditory.
>
>Jay
>
>
Yeah, this is good advice for those out there who wipe out at all, or
this "biffing" thing as you call it. (I'm not real familiar with this)
Steven Eric Romer
>Steve A-#1 rider in the world
>94 XR650L dream cycle
But seriously,
Think of this: if the bike for some odd reason catches fire, the tube
will melt off and spew a few gallons of gas onto the poor machine. Bad
scene man--happened to one of my minibikes. My brother still laughs at
the look on my face he saw when the hose I ran for wouldn't reach :-(.
I just remember the grips going whiz whiz as each drop of
burning/melting grip dropped off!! Turns out we totally restored the
thing--mom even sewed a new seat cover (thanks mom) for the new foam I
put in there. New paint, grips, etc. too. But I guarantee you don't
want to go through this. This is a good reason to turn the gas off.
Steven Eric Romer
Steve A-#1 rider in the world
94 XR650L dream cycle
dust...@my-deja.com wrote:
>Yes, removing the Petcock would be way cool...
>
>That way we, someday, may get to read the following type of posts:
>
>Removed Gas Tank, Gas spilled everywhere...
>
>Why does my motor not run, now that my bike burned up.
>
>Laid bike over, gas went everywhere, garage caught on fire, damn bike
>makers! who do I sue?
>
Steven Eric Romer
"M. Williams" <mwil...@deletethistoemailme.crocker.com> wrote:
>dust...@my-deja.com wrote:
>>
><snip>
>>
>> Laid bike over, gas went everywhere, garage caught on fire, damn bike
>> makers! who do I sue?
>
Dave Dude
>>Why do
>>motorcycles have these things? It's just one more thing to clog up.
>
>Lets see, I’m not an expert but let’s try it.
>
>I turn my petcock off to pull my fuel tank off the bike during maintenance.
>Which by the way is at least once a week. I can then set the tank (with gas in
>it) just about anywhere without having to drain it.
>
>I also turn it off while I am trailering my bikes so that while they are
>bouncing up and down their not draining their fuel contents all over my
>enclosed or open trailer.
>
>It’s also convenient to shut off the flow while going through the process of
>re-jetting a bike at track side.
>
>I’m sure there’s more let’s think about it.......
Yeah, if the needle valve leaks by and your crank seals are bad then
your cylinder AND tranny won't fill up with fuel.......
Dave dude
96yz250
fas...@my-deja.com
> >
> >You can use it to teach your bike good manners. I shut the gas off if
> >the bike is doing things I don't like. Be sure to tell the bike why
> >you are punishing it. I say "OK, I've had it with your two-wheeled
> >shenannigans!!--no gas for you! Time out!!" when I turn it off.
> >Doesn't happen that often on the dream cycle of course, but it is
> >effective--the bike quiets right down!
> >
> >Steve A-#1 rider in the world
> >94 XR650L dream cycle
>
> But seriously,
>
> Think of this: if the bike for some odd reason catches fire, the tube
> will melt off and spew a few gallons of gas onto the poor machine. Bad
> scene man--happened to one of my minibikes. My brother still laughs at
> the look on my face he saw when the hose I ran for wouldn't reach :-(.
> I just remember the grips going whiz whiz as each drop of
> burning/melting grip dropped off!! Turns out we totally restored the
> thing--mom even sewed a new seat cover (thanks mom) for the new foam I
> put in there. New paint, grips, etc. too. But I guarantee you don't
> want to go through this. This is a good reason to turn the gas off.
>
> Steve A-#1 rider in the world
> 94 XR650L dream cycle
>
>
And you guys think I ride with both feet off the pegs.
Freddie
--------------------------------------------------
My father always said, "It ain't the size
of the pencil it's how you write your name."
In retrospect, I think that was just a
way to get out of buying me pencils.
Squeky
>petcock's even when parking for just a few minutes. Why?
Oh oh oh, I know, I know. When I park my bike in the dirt, and it
tips over, I like to have some gas left after I pick it back up. Once
I forgot, parked my bike, went working in a shed for while, came back
out and guess what??? Gee, I was down to 1/4 tank! Maybe this is why
people like turning their gas off. Turn off the gas and maybe all
that is lost is gas in the bowl and a scratch in the Barkbusters.
------------------------------
Squeky
1986 XR600R
http://www.netcom.com/~squeky1
squ...@ix.netcom.com
------------------------------