2003 HD Sportster XL Custom

I'm having some problems with it dying on me while riding.I'm not sur
whats going on but I took my kid for a ride and we ran out of gas, so
pulled or should i say we pushed it and filled it. Then all of a sudde
it stopped running and shut down. Had to wait awhile before startin
it.It was hard to start and seemed like if I gave it gas it stil
wouldnt turn over. When it did start I went on only to have it buck o
me and then die again. I've heard it could be an ignition problem? An
suggestions

 

Does that model have a Mikuni constant vacuum carburetor on it? If so,
I will tell you the same thing I tell people who have Japanese
motorcycles with Mikuni or Keihin constant vacuum carburetors with the
big round cover on top.

Those carburetors have really tiny idle passages and really large idle
jets. It doesn't matter how big the idle jet is, if the idle passages
get plugged up with gum and varnish, the engine will idle OK, but it
will die when you open the throttle.

You might try putting about 3 ounces of Berryman's B-12 Chemtool Choke
and Carburetor Cleaner in a full tank of gas and going for a putt. The
B-12 will clean out the carburetor and the idle RPM will increase, so
you may have to stop and turn the idle speed down.

Find out where your idle speed knob is and get to know and love it. A
rider who doesn't know where the idle speed knob is shouldn't be riding
anyway.

You can buy Berryman's B-12 at Wal*Mart for less than $3.00 for a 15
ounce can of the liquid kind, or you can buy the aerosol can and spray
it into a measuring cup before dumping it in the gas tank.

No, I do not own stock in Berryman's or in Wal*Mart, and I do not
distill Berryman's in a shed out in the woods. It's just that the stuff
is so cheap and it cleans out carburetors so easily. I use B-12 in my
gas tank about three or four times a year to keep my carburetors clean.

 

It's never a good idea to run any vehicle out of fuel. Both
for obvious reasons, and reasons such as this.


Gary

 

Something that sounds daft but actually happens is that the air
inlet in the tank cap gets blocked. This will create enough vacuum in
the tank to stop petrol flow after riding for some time.
You can test if this is your problem by opening the tank cap the
next time you experience the same problem. Listen for a whoosh
sound. If the engine starts and runs fine after just opening the
cap this could be your problem.

 

Or it could just be that the 'original' fault was not lack of fuel?

 

Please explain both the "obvious" reasons and how this relates
to the original posters problems.

 

Well. the obvious reason(s) is/are :
You may have to walk
Your passenger may have to walk
You & your passenger may have to walk, and walk a
very long distance.
You may have to buy a gas can that you'll either discard
after refilling the bike, or have to tote with you.
Your bike could be stolen while you're hiking for gas.
You bike could be vandalized while you're hiking for gas.
I've recently heard of various city imposed towing of
vehicles abandoned on their highways. I suppose that a
dry fuel motorcycle, with an out of sight owner just might
qualify.

"Are you catching on yet"?

And, regarding the relevance to the OP's dilemma:

Many times, but not always, I have seen vehicles run very
poorly, or not at all, after allowed to run dry on gas. This
has usually been attributed to a residue trash entering the
system in the absence of fuel. Although just theory, it can
certainly be possible. So, why create the exposure?

Questions?

Gary

 

Thanks guys! It ended up needing a new air filter, a new 190 jet and
circuit breaker. Well it should be ready for saturday. Thanks all fo
your help

 

OK, that was a bit too obvious for me. As we mainly post
about the technical aspects of motorcycling here, I
thought you meant some sort of direct damage caused
by running dry.

Now that there are more and more bikes that have
catalytic exhaust cleaning, there might actually be some
good technical reason not to run dry on these models.
OTOH, bike catalytic systems are AFAIK a bit different
from on cars.

Let's stay away from "vehicles" and stick to bikes. We
don't want to even think about old diesels where you were
in for a spannering orgy of venting and priming if you ran
dry.

In an old fashioned bike tank with a reserve position on
the petcock, the critical moment is when you turn on the
reserve. The fuel is then taken from a point much closer
to the bottom of the tank and the engine can get a gulp
of for example water that has been sitting at the tank
bottom.
If the bike does not have a screen around the tank outlet
there could be a lot of rust or other crap as well. Anyone
running a fuel system with no filtration deserves this.

If there is no reserve position, maybe not even a petcock,
there will be no lowering of the fuel outlet point and any
crap will flow into the carb no matter how much fuel is
in the tank. Until the tank is empty, of course.

On bikes with fuel injection, where I have no personal
experience, I guess it will take a while to flush the air out
of the system.

 

My 2000 Honda has never even seen reserve. Not bec-
ause I fear some kind of operational abnormality, I just
try to keep the tank full. My earlier reference to "vehicles"
was merely meant to preclude someone's comments that
"hey, that can happen with cars too".

Personally, I've never run any vehicle type out of gas. But,
I've witnessed others do it, sometimes with no harm, other
times with similar consequences as described by the OP.

But, it seemed like some additional factors were present
in her/his final diagnosis.

Gary

 

Well, it might have been electrical. If the electrical circuit to the
ignition doesn't make good contact, the motorcycle just might buck and
jump as the ignition cuts out irregularly.

The 190 main jet would have nothing to do with the starting problem you
described, you only use the main jet when the engine is running at wide
open throttle and that occurs about 1% of the time for cruiser riders.

The air filter is a maintenance item. It would have to be very dirty to
keep the engine from starting.

 

Ok maybe I have someone who is fixing my bike and knows nothing,
don't know. All I know is that it still bucks and then in a while i
will shut down . Im at my wits end. I would take it to Harley but I'l
pay a mint. My brothers friend is a Sportster racer and fixes his ow
bikes. I hope he can fix it

 

Well, all those certificates on the wall at a mechanic's work station
are no substitute for experience. The mechanic goes to the school, pays
the fee, and they are going to give him the piece of paper he paid for.
If mechanics went to the Motorcycle Mechanics Institute and didn't
pass, they wouldn't get more students would they?

Try the Berryman's B-12 carburetor cleanout I recommended.

Mikuni constant vacuum carburetors have really tiny idle passages and
really large idle jets. It doesn't matter how big the idle jet is, if
the idle passages get plugged up with gum and varnish, the engine will
idle OK, but it will die when you open the throttle.

You might try putting about 3 ounces of Berryman's B-12 Chemtool Choke
and Carburetor Cleaner in a full tank of gas and going for a putt. The
B-12 will clean out the carburetor and the idle RPM will increase, so
you may have to stop and turn the idle speed down.

Find out where your idle speed knob is and get to know and love it. A
rider who doesn't know where the idle speed knob is shouldn't be riding
anyway.

You can buy Berryman's B-12 at Wal*Mart for less than $3.00 for a 15
ounce can of the liquid kind, or you can buy the aerosol can and spray
it into a measuring cup before dumping it in the gas tank.

Well, he should at least be able to show you the idle speed knob. Shade
tree mechanics have a lot of enthusiasm, but they tend to have
simplistic ideas about what might be wrong with a machine and they
really do not understand constant vacuum carburetors.

It took me thirty years to find out why constant vacuum carburetors do
some of the mysterious things they do.

Then there is the business with the circuit breaker. Many mechanics
will experimentally replace electrical parts that they don't understand
the function of.

The circuit breaker is like a fuse, except there is a button to reset
it if it trips off because of electrical overload.

If you had too much electricity flowing through the wires and that made
the circuit breaker trip off to protect the circuit, replacing the
circuit breaker would be most illogical, as it wouldn't fix the reason
for the electrical overload and the wiring would eventually burn up.

It is conceivable that the electrical contacts inside the circuit
breaker weren't making good electrical contact though.

But you say that the motorcycle still bucks after the circuit breaker
was replaced, so I recommend cleaning out the carbs with B-12.

And, you can check all the electrical connections coming out of the
ignition switch and the connections on the ignition coils and the
signal generator and the ignition control box to see if they are tight.
Your brother's friend should be able to help you find all those
connectors.

 

While I was thinking about loose electrical connections, you might also
look at the side stand and the clutch lever to see if there are
electric switches that are operated by moving the clutch lever or
putting the sidestand up or down.

I don't think Harley Davidson puts things like that on their
motorcycles yet, but all the
Japanese manufacturers do. And dirty contacts in side stand switches
will cause the motorcycle to suddenly buck and the engine will quit.

Also, if the engine quits like that, work the kill switch and turn the
ignition key on and off and feel the back of the ignition switch if you
can get your hand behind it.

If the ignition switch is getting really hot, it has bad contacts and
can cause the engine to shut off unpredictably.

 

Yeah, like when your GF backwashes in your coffee and it tastes funny,
but you drink it anyway, because it won't hurt ya?

Whoever gave you that advice wasn't thinking about what tiny bits of
rust and dirt can do to the tiny passages in a Japanese carburetor.
Even if you have an add on gas filter, water will go right through it
and build up in the float bowls.

So my recommendation is to NEVER use the reserve position on the
petcock unless it's a real out of gas situation and you are stuck miles
from a gas station.