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[ric97]

I had the dealer install and dyno tune the Big Shots Long (with quiet baffles) and SERT on my 06 Fat Boy SE with 103 engine. When I first started the bike and drove home…I was happy with the sound and performance. Gradually…over the past 3 weeks…I have noticed more and more decal popping that was not there when I first drove home. As of yesterday, it is very loud and noticeable. In fact, yesterday I tried starting the warm engine and heard a psssft (sounds like air flowing from a tire…but it is a backfire-type event) and then I saw smoke rising from under the gas tank – I could not tell if it was coming from the exhaust manifold or the air cleaner. I heard the psssft backfire sound more when I would lightly rev the engine before downshifting (matching the RPM to the lower gear). What is going on? Any help would be appreciated.

[Fatboy]

Your pipes are loose and not properly sealed at the heads.........

 Did they install new gaskets when they put your pipes on? They probably should have.

 Take it back and ask them to fix it.  [smiley=xyxthumbs.gif]

[grc]

ric,

Definitely sounds like an exhaust leak at the heads.  Take a quick look and check to see if the nuts holding the exhaust pipe flanges to the head are tight (or even there).  Many folks don't properly tighten the flange nuts (evenly side to side, in gradual steps, with a torque wrench), and having one or more nuts loosen and eventually fall off is not an uncommon thing after installing new pipes.  In any case, take it back to the dealer and have them fix it properly (new gaskets, evenly tightened flange nuts, proper torque spec).

Jerry

[erniezap]

New pipes heat up and cool down and the bolts loosen up.  It's typical, and you should retorque your pipes at the heads about 1-2 weeks after installation (once the pipes take their final shape).

[ric97]

Thank you for your help. I checked and the nuts are there...will check the tightness after I get the torque specs from V&H...I did not get the installation instructions when I picked up the bike. I did pay for new gaskets...so I really want to assume they are on. Are the bolts welded to the manifold or are the easily replaceable?

New question...if I had the bike manually tuned on a dyno with the stock air filter (stage 1 but not K&N or Zippers)...and assuming it is running right after the bolts get tightened (assuming that is the problem)...would I need to have it retuned if I go to a K&N filter?

You guys are awesome...thanks again!

[grc]

ric,

The attachment at the head is by way of two nuts which screw onto studs attached to the head.  If the studs were to get damaged, they can be replaced with effort.

The H-D torque spec for the nuts is 100 to 120 in-lbs.  That is not much, so make sure the threads are clean and the nuts easily start onto the threads.  Rough threads will cause you to reach torque before the pipes are actually seated.

It is unlikely that you would need to retune after changing from the SE filter to the K&N.

Jerry

[ric97]

Jerry,

Thank you for your comments. I hope to get to it tonight. I am hopeful that it is just loose pipe nuts...

Ric