thunderheader tuning problems
Road Warrior
Joined: Dec 2007
Posts: 1,286
Likes: 64
From: SoCal
RE: thunderheader tuning problems
Good luck mav7500. I hope I ain't sending you off in the wrong direction, but I don't know what else it could be. I hope torque cones are the solution. If it is reversion, then the anti-reversion stuff in that new exhaust sure isn't doing its job. What did the indy shop say?
Novice
Joined: Feb 2008
Posts: 24
Likes: 0
From:
RE: thunderheader tuning problems
I've got one on my shovel with an \\;S&\\;S"B", it runs fine, try to disconnect the accelerator pump \\; and give that a try, make sure you don't have any air leaks at the intake manifold
Road Warrior
Joined: Dec 2007
Posts: 1,286
Likes: 64
From: SoCal
RE: thunderheader tuning problems
mav7500, I hope this post goes through. I wanted to tell you all engines have reversion to some degree somewhere in their rpm range. What you are trying to do is lessen it at this particular rpm range. \\;
Intermediate
Joined: Apr 2007
Posts: 40
Likes: 5
From:
RE: thunderheader tuning problems
Mav7500, I agree with Megawatt on his thought concerning reversion. I had similiar troubles when I changed my exhaust. I replaced my carb and cam trying to fix the problem, but ulimately had to change my mufflers......again
......to get the bike running right.
 \\;
Here's a thread I'd started about mine: https://www.hdforums.com/m_2269484/m...tm.htm#2269484
 \\;
Good Luck!!
 \\;
 \\;
......to get the bike running right.  \\;
Here's a thread I'd started about mine: https://www.hdforums.com/m_2269484/m...tm.htm#2269484
 \\;
Good Luck!!
 \\;
 \\;
Road Master
Joined: Jul 2007
Posts: 1,009
Likes: 4
RE: thunderheader tuning problems
Bend the edges of the baffle out toward to muffler wall. \\; Try two at first and then three. \\; If that dosn't work you can always bend them back to their original position.
Road Warrior
Joined: Dec 2007
Posts: 1,286
Likes: 64
From: SoCal
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Novice
Joined: Jun 2008
Posts: 20
Likes: 0
From:
RE: thunderheader tuning problems
What cam are you running and what jets do you have? Engine displacement also. I will tell you torque cone are useless in any motor. Reversion to the point of spitting fuel with the proper jets usually is affected buy cam duration vs. cylinder fill \\;and can be corrected to a point \\;with changing the main air bleed to bring in the main jet either sooner or later and worse case adding a third fuel circuit i.e. a thunderjet.
Cruiser
Joined: Dec 2005
Posts: 104
Likes: 0
From: NH
RE: thunderheader tuning problems
Sorry you have such a pain with that thundeheader - I run a 2-1 on my 74" shovel and it runs like a rapped ape. \\; Motor has Andrews cam, s&\\;s super E shorty, perhap other head or valve work I'm not sure, I bought it as is rebuilt. \\; First I had short straight pipes, it ran fine, then added the thunder and it still ran great ableit with better horsepower as you revved trough the rpms. \\;
 \\;
Like someone said - be sure to double check for any intake leaks in the carb-intake manifold, they are infamous for leaks in that area (I fabricated a metal tab to brace the cab to the top motor mount bolt to hold that sucker very solid). \\; Also make sure you have a good seal of the exhaust port too, I used the early evo-style gaskets on top of shovel gaskets (pursuant to good advice obtained on this forum).
 \\;
best of luck
 \\;
Like someone said - be sure to double check for any intake leaks in the carb-intake manifold, they are infamous for leaks in that area (I fabricated a metal tab to brace the cab to the top motor mount bolt to hold that sucker very solid). \\; Also make sure you have a good seal of the exhaust port too, I used the early evo-style gaskets on top of shovel gaskets (pursuant to good advice obtained on this forum).
 \\;
best of luck
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jpnelson1978
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