Can not get gas into cylinder?

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Karl
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Can not get gas into cylinder?

#1

Post by Karl » Sun Sep 04, 2011 10:35 am

Hi fellows, first post here.

(Bear with me and my language, I´m Swedish..)
So, here we go...

1964 Panhead. Not much is stock or untouched.
Bought it some years ago, it had been tucked away in a dark corner for 17 years.
When I kicked it over, I was struck by how hard it was to turn over. Turns out that the former owner rebuilt it with different cam higher compression pistons, and god knows what else...
I had it running, but it ran pretty poor. A lot of backpulses and coughing back out through the airfilter, occationally with a little flame...
Ok, no good I thought. I did not want to set the damn thing on fire.

So instead of breaking my leg on the kick, and set her on fire, I decided to try and get the bike down to a more userfriendly scoot.
Some time later, (years) here´s where we are at today:

Standard cam.
Thicker head gasket
New big battery, 20 AmpHrs.
Solid lifters.
CV carb, all cleaned out twice, mounted on a S&S intake.
Mallory ignition.
New coil.
New ignition leads.
New plugs.

I get spark, nice fat and blue.
I get gas to the intake, but not further..?
The sparkplugs are all dry, and when I kick her over with the plugs out, there is no whiff of gasoline coming through the sparkplug hole.
There ´s no smell of gasoline through the exhaust neither?

But when I look through the carburettor, into the intake, I can see a small lake of gasoline inside, just waiting to be flushed into the cylinder.
But somehow it does not get there..?

So now:

1. I set the timing as I understand it is supposed to be set.
Front cylinder in compression stroke, turn engine over ´til the "I"-mark is visible throught the inspection hole.
At that moment, the red diod on the Mallory goes on.
2.The valves open and close as they should. I even had the rocker cover off in order to visually see the valves movement.
They look fine.
3. Gas is there, can even see it in the bootom of the intake.
4. Spark is there.
It seems like there´s no gasoline getting through
5. Kick like a sonofab..

Nothing..
Not even a "hohtt" or a "Phhtt"
It´s just stone cold dead.

The cam was installed with the marks properly aligned.
The lifters have the right freeplay so they can be spun when "relaxed"

Is it possible that the previous owner reinstalled some cogwheel or such wrong?
How about the pinion, can it be installed wrong?
I´m in the dark here.

Q´s:
1. Is there anyway to "Reset" the engine?
2. Could it be so that the timing is set wrong after all? I read some threads in this forum that the "I" -mark should be just visible in the hole, I.e not centered, but just coming into view from the right.
3.But still, it does not explain why is there no gas into combustion chamber?

Whatever ideas you have...
/Karl



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Re: Can not get gas into cylinder?

#2

Post by 1950Panhead » Sun Sep 04, 2011 12:17 pm

One thing to check is cam timing, pull the plugs, put front piston at top, put a piece of tape on the engine sprocket, turn engine forward with wrench, intake valve should open just before top dead center and stay open until bottom dead center (watch pushrods).
Exhaust should open just before bottom dead center and stay open until top dead center. Some camshafts have pressed on gears, gear pressed wrong it won't run. Both valves closed when points open (spark).
Another thing to check is for intake leaks, search forum.
Jerry

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Re: Can not get gas into cylinder?

#3

Post by john HD » Sun Sep 04, 2011 12:45 pm

karl

welcome to the forum!

the CV carb has an enrichner on it instead of a choke.

the throttle must be completely closed in order for it to work. try giving it 3 or 4 prime kicks with the throttle closed and the ignition off, the try a hot kick with the ignition on. it should start right up.

if that doesn't work, double check that you do not have any intake air leaks.

john

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Re: Can not get gas into cylinder?

#4

Post by Karl » Sun Sep 04, 2011 2:04 pm

Thanks for the input guys!


Still, the main issue remains. Why can´t I get gasoline into the cylinder?

I´m in the garage now, and just checked alignment on cam. All marks line up fine, so all is good there.
The valves open and close at the right moments. All good there too.

Since I installed a Mallory distributor now, there´s no breaker points anymore.
But that does not matter, as I hade the same problem before with breaker points distributor on. So it has nothing to do with the spark.

If I kick the engine over, and close the air intake with the palm of my hand, it feels like I´m about to get sucked into the intake.
Shouldn´t this be enough to suck in gasoline?
So why are my plugs still dry?

Any tip on how to check for intake leaks with a dead engine?

Thanks again guys!
Karl


@ Jerry, what was that with putting tape on engine sprocket? What does the tape do?

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Re: Can not get gas into cylinder?

#5

Post by steve_wood » Sun Sep 04, 2011 4:56 pm

Karl:

Can you run a compression test? Although you may feel suction on your hand, it would be best to get a more accurate assessment.

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Re: Can not get gas into cylinder?

#6

Post by john HD » Sun Sep 04, 2011 6:24 pm

karl,

did you try starting it as i suggested?

john

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Re: Can not get gas into cylinder?

#7

Post by Karl » Sun Sep 04, 2011 7:48 pm

steve_wood wrote:Karl:

Can you run a compression test? Although you may feel suction on your hand, it would be best to get a more accurate assessment.
Hi Steve,

Compression test might be one of the next steps I guess.
However, I had an Ironhead before, and whomever tried to kick one of those over knows about compression. I would say this pan is close to that.
I´m pretty sure it has compression in a bunch. I´ve been wrong before, but lack of compression is not the first thing that comes to my mind here.

Besides, I had it running before, and the engine sounds really good.
-It did not run clean, but still, the engine sounds good.

You know, the problem is; It does not even cough. No "poof" or "FFFhhh" -s whatsoever.

But all ideas is as good here. Keep on brainstorming...

Thanks!
/Karl

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Re: Can not get gas into cylinder?

#8

Post by Cotten » Sun Sep 04, 2011 7:52 pm

Karl and All!

Plugs need not be wet for a motor to start.
In fact, it indicates flooding.

A puddle in the manifold is not desireable, and along with "A lot of backpulses and coughing back out through the airfilter, occationally with a little flame..." are signs of a vacuum leak, as Jerry and John noted.

A very detailed description of leak-testing has been provided by our member Steve Wood: viewtopic.php?f=5&t=9095

A brief discussion of basics can be found at [url]http:virtualindian.org/11leaktest.html[url]

A large rubber stopper works as well as a testplate, but requires three hands!

Beware that even modern manifolds can display casting porosities in places never imagined:
S&Spore2.jpg
S&Spore2.jpg
And I have a question about CV carburetors, of which I have no experience: Is there a support bracket that fits them to a Pan?

....Cotten
PS: Wow!
I re-sized a huge photo, deleted the first upload, uploaded the smaller, and now there are two of them!
And only one shows up to delete upon "edit".
....Sorry...
You do not have the required permissions to view the files attached to this post.
Last edited by Cotten on Sun Sep 04, 2011 8:07 pm, edited 2 times in total.

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Re: Can not get gas into cylinder?

#9

Post by steve_wood » Sun Sep 04, 2011 8:03 pm

Slightly more up-to-date version here in the Knowledge Base:

viewtopic.php?f=59&t=9139" onclick="window.open(this.href);return false;

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Re: Can not get gas into cylinder?

#10

Post by john HD » Sun Sep 04, 2011 8:13 pm

Is there a support bracket that fits them to a Pan?
only custom made!

i made one from a modified aircleaner backing blate and a piece of steel strap.

my linkert is much easier!

john :D

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Re: Can not get gas into cylinder?

#11

Post by Karl » Sun Sep 04, 2011 8:18 pm

john HD wrote:karl,
did you try starting it as i suggested?
john

Hi John,

Unfortunately I do not think the carb is the culprit here, however I do agree that carbs must be designed to Satan himself. Carbs are the root to all evil...
I see it this way;
An engine needs 3 things to run.

Air, fuel and ignition.
Compress air and fuel and ignite, thats it.

1. The bike gets fuel, and lots of it. as I said before, when I open the throttle and look all the way to the bottom of the intake, to right where it comes to the "T"-junktion leading to the intakevalves, there is gasoline floating there from all the kicking and jetting.
But there´s no gasoline in the combustion chamber. The sparkplugs are still dry as new.
2. Ignition is good to, timing of ignition is not 100 yet, but I installed according to the Mallory instruction sheet, so I should at least get a "Huff"

When I kicked it over today, there was no response att all. It was as dead as if you would kick it over without a key in it.
But here´s the real snag:

When I remove the plugs and kick it, there´s no smell of gasoline coming out from the combustion chamber.
I had my friend sniff the exhaust when I turned engine over, and no gasoline smell from there as well.
But when I peep into the

It´s like the valves wont let gasoline into the cylinder for some reason.
Even though I triple-checked clearance for pushrods, timing is spot on and set for compression stroke, it´s all dead...
What the hell is going on?


So now I´m looking for some way to "reset" the engine. To get it from square one and start all over again.

But thanks for the inputs John, keep ideas coming!

/Karl

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Re: Can not get gas into cylinder?

#12

Post by john HD » Sun Sep 04, 2011 8:30 pm

karl,

panheads need a lot of fuel to start. so i think you are not doing anything particularly wrong. yours sounds like mine when i had a CV on it with a massive intake leak. double check that as cotten suggested.

one other thing to consider. today's modern spark plugs are NOT glazed on the tip, they are designed to be run with fuel injection systems. so once they get wet they are junk. even once!

i know you think you are not getting enough fuel.

just for laughs, try a brand new set of plugs and give it a couple of prime kicks (throttle closed, enrichner engaged) with ignition off. then one hot kick (ignition on enrichner engaged throttle closed) and see what happens!

john

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Re: Can not get gas into cylinder?

#13

Post by Cotten » Sun Sep 04, 2011 8:34 pm

Karl wrote: ....carbs must be designed to Satan himself. Carbs are the root to all evil...
Karl!

Modern carbs perhaps!
But carbs of the era were phenominally forgiving, I assure you!
(Otherwise, I would never do them for a living.)

I have found that no carb will perform if there is a vacuum leak. It is not just "Compress air and fuel and ignite", it is enough compression, just the right amount of air, and ignite at the right time.

Manifold leaks are evil.

Please leave no stone unturned, and bubble-test your manifold assembly first.
With a Pan, it is also prudent to test the pancover screw over each intake port, as occasionally they have been perforated into the port.

From my perspective, electronic ignitions are evil too!
Perhaps there is a little switch upon it for "Kick" as opposed to "Electric Start"? (That befuddled me once, and has me shy of such gadgetry ever since.)

.....Cotten

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Re: Can not get gas into cylinder?

#14

Post by beets » Sun Sep 04, 2011 8:40 pm

Pull the spark plugs and put about a spoonful of gasoline in each head. Put the plugs back in and try to start it.

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Re: Can not get gas into cylinder?

#15

Post by Karl » Sun Sep 04, 2011 9:31 pm

Cotten wrote:Karl and All!

Plugs need not be wet for a motor to start.
In fact, it indicates flooding.
A puddle in the manifold is not desireable, and along with "A lot of backpulses and coughing back out through the airfilter, occationally with a little flame..." are signs of a vacuum leak, as Jerry and John noted.
A very detailed description of leak-testing has been provided by our member Steve Wood: viewtopic.php?f=5&t=9095
A brief discussion of basics can be found at [url]http:virtualindian.org/11leaktest.html[url]
A large rubber stopper works as well as a testplate, but requires three hands!

Beware that even modern manifolds can display casting porosities in places never imagined:
S&Spore2.jpg
S&Spore2.jpg
And I have a question about CV carburetors, of which I have no experience: Is there a support bracket that fits them to a Pan?
Hey Cotten!

Thanks for the intake-link
I´ll do the leak test tomorrow if can manage it timewise, otherwise It´ll have to be next weekend.
Of course, a puddle in the intake is not what I am hoping for, but it shows that gasoline gets there, but no further.

Perhaps I was a bit unclear with the timespan here.
I wrote that it backfired and shot gusts out through the airfilter before, but that was the last time I had it running.
That was last summer and since then I had the engine stripped down to just the block, and I would not call it a complete overhaul, but a lot of things are replaced and renewed.

We do not want to find wet sparkplugs in a working engine, that is true. As you said, that is not an ideal fuel/air mixture for an engine.
...But this engine is not running...
I have had at least 10 different bikes in all kinds of categories, and never experienced this problem.
When ever you drown an engine with to much gas, you will always end up with wet sparkplugs.
So after some 20 revolutions of the engine and no combustion, we should be able to find fuel inside the combustion chamber or what?
But not here...
So I´m thinking, why is that?
Something is really not right here.

Follow me through this one:

-If the intake valve opened as it should. And we have a puddle of gasoline just outside the valve.
At least some air/fuel would be sucked into the cylinder, leaking intake or not.
And if not ignited, we would find fuel in the cylinder.
-But we don`t.

I have new O-rings on the intake manifold + Hylomar on all joining surfaces.
I do agree leaks will get the engine running poorly, and I´ll look it through thoroughly.
But it has to be a big leak if the engine should give no response at all.

At least we should get a hesitant engine cough or something, but there´s nothing at all...

1. It has good spark. All electrical components are brand new.
2. It has compression. I know this beacuse it ran at least fairly ok before.
3. It has gasoline, no shortage of that.

But 4. It has NO air/gas flow through the engine...
And without it, how can we get the gas/air mixture to ignite?

Desperation showing yet? Haha!

Thanks Cotten,
/Karl

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