Author Topic: Gotdang Intake leak  (Read 905 times)

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Offline PJultra

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Gotdang Intake leak
« on: September 13, 2020, 02:03:42 PM »
I keep getting an intake leak on the front cylinder. I try and I try. I am running a  carb, used to be EFI.
I slightly snug the manifold, install the carb and air cleaner assembly, then slightly tighten the 2 manifold bolts and 1 allen screw that I can get to. Can't get to the front carb side allen when the carb is on.
Then I remove the air cleaner assembly and remove the carb, and then tighten down the intake manifold.
I have good seals and even tried the blue ones (which I am going to try again). And I put a little dishwashing soap on the cylinders so that the manifold slides in nicely.
I did not have this issue when it had an EFI throttle body manifold.
Any suggestions? Buy another manifold?
My old shovelhead manifold was better and easier then these evo manifolds.

Offline Ohio HD

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Re: Gotdang Intake leak
« Reply #1 on: September 13, 2020, 02:22:35 PM »
Maybe the clamp flanges are flexing / bent? Try different flanges.
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Offline PJultra

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Re: Gotdang Intake leak
« Reply #2 on: September 13, 2020, 02:30:41 PM »
Maybe the clamp flanges are flexing / bent? Try different flanges.

I do have another set. I didn't think of that. Thanx, I'll see what happens.

Offline nmainehunter

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Re: Gotdang Intake leak
« Reply #3 on: September 13, 2020, 02:53:27 PM »
There isn't much room to do any work with the carb on. Get a solid manifold and put that on first then put the carb on. It's way easier.

Offline fbn ent

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Re: Gotdang Intake leak
« Reply #4 on: September 13, 2020, 03:00:46 PM »
If you are not removing the tank, try that....way more access.
'02 FLTRI - 103" / '84 FLH - 88"
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Offline Deye76

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Re: Gotdang Intake leak
« Reply #5 on: September 13, 2020, 03:51:36 PM »
"Maybe the clamp flanges are flexing / bent? Try different flanges."
 :up:

East Tenn.
2014 CVO RK, 2015 RGS, 1992 FXRP

Offline PJultra

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Re: Gotdang Intake leak
« Reply #6 on: September 13, 2020, 04:48:05 PM »
Different flanges, leaking front and back cylinder.
Tomorrow after work I will try the thicker blue seals and see if that helps.
I've done it so many F'n times now, I can pull everything apart and have it back together in half an hour. Including the dang throttle cable.
I'm tired of doing it.........   :angry:

Just had a thought. Could it have to do with the Ness air box? Maybe causing some sort of misalignment???

Offline JW113

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Re: Gotdang Intake leak
« Reply #7 on: September 14, 2020, 03:38:11 PM »
Just so we have the same understanding, how are you detecting that the intake manifold is leaking?

And how tight are you cranking down on the bolts?

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Offline PJultra

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Re: Gotdang Intake leak
« Reply #8 on: September 14, 2020, 04:13:28 PM »
Just so we have the same understanding, how are you detecting that the intake manifold is leaking?

And how tight are you cranking down on the bolts?

-JW

I'm spraying the intake manifold from the left side with carb cleaner, bike almost dies. After the bike is hot from riding, it will cough cough blurp blurp when I shut off the ignition. I can turn the air mixture screw all the way in with 0 change.
As far as how tight, pretty dang tight, but not using a torque wrench.

Offline Burnout

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Re: Gotdang Intake leak
« Reply #9 on: September 14, 2020, 09:35:34 PM »
Spraying from the left side you can be feeding fuel in the back of the air filter.

Dribble the cleaner on from the right side.  :^)

If you can close down the idle mix screw and the motor will still run, it is getting fuel from somewhere else like the "choke", or float level is not under control, or the air filter is full of fuel from reversion. Or worse yet gas in the oil.
« Last Edit: September 14, 2020, 09:39:36 PM by Burnout »
They don't call me Ironhead Rick just because I'm "hard headed"

Offline PJultra

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Re: Gotdang Intake leak
« Reply #10 on: September 14, 2020, 09:56:48 PM »
Spraying from the left side you can be feeding fuel in the back of the air filter.

Dribble the cleaner on from the right side.  :^)

If you can close down the idle mix screw and the motor will still run, it is getting fuel from somewhere else like the "choke", or float level is not under control, or the air filter is full of fuel from reversion. Or worse yet gas in the oil.

I put a different air box on, one that has the breather bar that runs over the carb and looks like crap.
I sprayed carb cleaner from the air box side and the front is good, but the rear is sucking it in.
What do you mean when you say "float level is not under control"?
I'm not suspecting the choke as this is the 2nd carb with all the same issues.

Offline capn

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Re: Gotdang Intake leak
« Reply #11 on: September 15, 2020, 05:18:23 AM »
If you can try to tighten all manifold bolts with carb and AC backing plate mounted . In your case tightening 3 bolts might not be enough.

Offline JW113

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Re: Gotdang Intake leak
« Reply #12 on: September 15, 2020, 02:57:06 PM »
Sounds like more going on than just intake leak.

1. Those intake screws don't have to be all that tight. It is a compliance seal. If  you are putting a bit of arm on them, there is a chance you warped the head surface where the gasket seats against. Make sure that area is perfectly flat.

2. If you can bottom out the idle screw and the motor don't die, that is a problem. What cam are you using in this bike? The next time you have the carb off, look into the back side of the carb, down at the bottom of the throttle plate. Do you see any of the little transfer port holes exposed?

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Offline Deye76

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Re: Gotdang Intake leak
« Reply #13 on: September 15, 2020, 04:11:22 PM »
Have you tried new flanges? Or are you working with used ones?
East Tenn.
2014 CVO RK, 2015 RGS, 1992 FXRP

Offline PJultra

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Re: Gotdang Intake leak
« Reply #14 on: September 15, 2020, 07:43:42 PM »
OK. pulled it all apart again (after watching some videos on line). The flanges are not warped, The carb is tight in the front hole.
I'm not done yet, But I completely greased the (lightly) the flange seals and I am going to tighten the bolts/screws way more evenly. Each one 1/4 turn at a time to try and get them as even as possible.
I have an old carb body that I am going to strip everything off of so that I can get to the breather side allen screws with the carb on.
J.W., I am tightening the screw/bolts pretty good but I am not putting all my muscle into it. I wouldn't think that I've tightened them so tight that I warped the surface. If all else fails, I will have to check that out.
I will look at the ports, but I have a feeling it's because of the intake leak. I remember you told me about those ports before. It is something I will keep my eye on.
I go to you guys for help because I respect your help. Thank you guys.

Offline Deye76

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Re: Gotdang Intake leak
« Reply #15 on: September 16, 2020, 06:14:10 AM »
"The flanges are not warped,"
If you checked them going by Scooter Tramp Scotty's video, you might want to spend $30.00 on new ones.  :teeth:
East Tenn.
2014 CVO RK, 2015 RGS, 1992 FXRP

Offline jeffscycle

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Re: Gotdang Intake leak
« Reply #16 on: September 16, 2020, 09:38:03 AM »
  Have the heads been shaved? Creating a shorter "V", then the manifold has to be trimmed down also, and possibly the holes & slots in the flanges need elongation. With just the manifold held up into place you should see a good match to the port from the inside.
'01 FXDXT, '99 FXDL/XRD, '76 FLH

Offline PJultra

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Re: Gotdang Intake leak
« Reply #17 on: September 16, 2020, 05:42:20 PM »
"The flanges are not warped,"
If you checked them going by Scooter Tramp Scotty's video, you might want to spend $30.00 on new ones.  :teeth:

Hahahaha.... I saw that.
No, I used my (not portable contractors) table saw table.

Offline PJultra

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Re: Gotdang Intake leak
« Reply #18 on: September 16, 2020, 05:44:08 PM »
  Have the heads been shaved? Creating a shorter "V", then the manifold has to be trimmed down also, and possibly the holes & slots in the flanges need elongation. With just the manifold held up into place you should see a good match to the port from the inside.

No head or barrel work done.

Offline Ohio HD

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Re: Gotdang Intake leak
« Reply #19 on: September 16, 2020, 07:45:15 PM »
Are you sure the flange bolts aren't too long?   
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Offline JohnnyCashPan

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Re: Gotdang Intake leak
« Reply #20 on: September 17, 2020, 01:36:13 AM »
Are you sure the flange bolts aren't too long?

Good point.  Also check the threaded holes for foreign material and correct thread depth.
Old, slow and fat...

Offline JW113

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Re: Gotdang Intake leak
« Reply #21 on: September 17, 2020, 08:18:08 AM »
No disrespect intended, but when things just don't add up, have to ask....

Which way are you installing the intake seals? Beveled side toward or away from head?

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Offline jeffscycle

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Re: Gotdang Intake leak
« Reply #22 on: September 17, 2020, 09:37:05 AM »
   could the flanges your using be '06^? should be older "F/R marked, slots to left side. Just asking, without pictures or personal examination, something is amiss.
'01 FXDXT, '99 FXDL/XRD, '76 FLH

Offline Burnout

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Re: Gotdang Intake leak
« Reply #23 on: September 17, 2020, 09:40:53 AM »
I suspect the intake is not right if it won't seal.
They don't call me Ironhead Rick just because I'm "hard headed"

Offline PJultra

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Re: Gotdang Intake leak
« Reply #24 on: September 17, 2020, 07:55:07 PM »
Sounds like more going on than just intake leak.

1. Those intake screws don't have to be all that tight. It is a compliance seal. If  you are putting a bit of arm on them, there is a chance you warped the head surface where the gasket seats against. Make sure that area is perfectly flat.

2. If you can bottom out the idle screw and the motor don't die, that is a problem. What cam are you using in this bike? The next time you have the carb off, look into the back side of the carb, down at the bottom of the throttle plate. Do you see any of the little transfer port holes exposed?

-JW

2. Yes , all exposed. Should there be any, except the air mixture screw?