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exhaust header pipe leak at head

T

the draggin

Active Member
:small3d023::small3d023:Okay so I have a 1997 Flhtcui. I changed the complete exhaust over to a newer factory set up with O2 bungs in 2008 in 2009 I had the engine done and put it back together and all was good. So for several years and about 15K miles now I have had no issues, now I have this leak at the head and can't cure it. I have replaced the donut gasket with a new thick one not the SE type but it doesn't seat and still leaks. So I took it apart and trial fit a new gasket to the header flange and it appears to have grown and the gasket doesn't even cover the flange opening. So if I press the gasket back into the exhaust port it will be tighter still. Okay I know it sounds impossible but. I'm at a loss as to what to do. Any help would be greatly appreciated. Thanks
 
Sounds like a real dilemma, is it possible the mouth of the header pipe somehow got distorted? It doesn't take much for it not to seal completely. 1 other issue could be it's not properly lining up to create a tight fit. You might try losing the other flange and see if that helps the alignment if it's a 2 into 1 exhaust.
 
I have loosened the complete system and still cannot get a good fit, this is really buggin me. Nothing has been done with it, it just started leaking.
 
I'd be looking at either a crack at the mouth of the header pipe or the pipe got so hot it distorted it. JMHO.
 
sorry for not getting back sooner, but it was the head gasket leaking right under the header. So now I'm into that and not sure what caused it. I usually don't have to run it when I start the day I just coast down the street with it in neutral and at idle for about a half mile and the high idle cuts off and then I have to stop. I usually just roll off the stop and go back to neutral to coast for another quarter mile. So I don't think warm ups are the problem. The head and cylinder seem smooth and flat using a stainless straight edge and there were no burn marks on either when I pulled it down. It had a cometic gasket set installed 3 years ago when I did a re-ring on it and has been running fine for about 10k. Maybe I just missed something.
:small3d023:
 
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Have a look here
Cylinder Head Installation
bullet Make sure the cylinder stud holes are clean and dry.
bullet Always use new head gaskets. Do not re-use head gaskets under any circumstances.
bullet Place new O-rings on the inserts and position the head gasket on the inserts.
bullet Be sure to clean and lubricate the cylinder head bolts before tightening them to the correct torque. Any dirt or grime on the bolts can cause additional friction, causing the torque wrench readings to be incorrect. Thoroughly clean the threads on the cylinder studs.
bullet Clean and lubricate the cylinder head bolt threads. Dip the head bolt threads in engine oil and wipe off any excess.
bullet Carefully place each cylinder head in its proper position, making sure not to move the head gasket from the proper position.
bullet Install the cylinder head bolts finger tight
bullet Tighten the cylinder head bolt using either the factory method or torque wrench method in the proper tightening sequence.
bullet If you reuse the OEM pushrods, make sure you place them in the proper order based on color codes.

We recommend the use of James Gaskets in your Harley-Davidson engine.


Warning

Install new O-rings over the cylinder dowels before installing the new head gasket. Installation of the O-ring first will ensure proper alignment of the head gasket.

The procedure for tightening the head bolts is extremely critical. Proper installation is required to prevent head gasket leaks, cylinder head stud failure, cylinder distortion or head distortion.

Head Bolt Installation
Factory Method

For each cylinder head, start with head bolt numbered one. In increasing number sequence (1-2-3-4), tighten the head bolt in three stages.

1. Tighten each bolt to 7-9 foot pounds of torque.

2, Tighten each bolt to 12-14 foot pounds of torque.

3. Mark each head bolt and head with aligning marks. Tighten each bolt 1/4 turn (90 degrees).

The factory method for installing cylinder head bolts is the same for all Evolution Big Twin and Sportster engines.


Head Bolt Installation
Torque Wrench Method

For each cylinder head, start with head bolt numbered one. In increasing number sequence (1-2-3-4), tighten the head bolt in four stages.

1. Tighten each bolt to 7-9 foot pounds of torque.

2. Tighten each bolt to 12-15 foot pounds of torque.

3, Tighten each bolt to 22-25 foot pounds of torque.

4, Tighten each bolt to 38-42 foot pounds of torque.

The torque wrench method of cylinder head bolt installation is used by James Gaskets and S&S

headbolt.GIF (1346 bytes)


Pushrod Color Codes

Front Exhaust is Green

Front Intake is Yellow

Rear Intake is Blue

Rear Exhaust is Purple
 
Thanks Jack, I'll be using cometic gaskets and I understand they have the proper sequence and torque spec on the tech sheet. I appreciate the feedback.

Enjoy the ride.
 
the draggin said:
Thanks Jack, I'll be using cometic gaskets and I understand they have the proper sequence and torque spec on the tech sheet. I appreciate the feedback.

Enjoy the ride.
Click to expand...

Do not install the O-rings at the cylinder dowels with a Cometic MLS head gasket.:s
 
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