A friend of mine said he had heard thathey was a way to mod the baffle to take out the torque dip in the the thunderheader. I did a search and come up with nothing but then i again i may not know how to search properly. Anyone know anything about this fix for the thunderheader?

 

For best results it needs to be modified a little at a time between runs on a dyno.The more cam overlap the more it's going to need modifying.

Look into the end of the Thunderheader.There's 4 triangular pieces that come to a point facing into the header.The widest part of the triangle being towards the rear of the header. To increase back pressure bend the wider part of the triangle towards the outer wall of the header. Repeat this for all four sides evenly.

 

Thanks for the info.

 

I know this is an OLDER thread but has anyone found/taken pictures of this mod? I recently got a Thunderheader for my 2012 Street Bob and would like to modify the baffle in the way you folks described...A few years ago I watched an '09 Yamaha RAIDER on the dyno after they'd intalled a SS SuperTrapp slip-on. They'd removed the disks and had only the END CAP to screw in (this IS not approved by SuperTrapp) As they screwed the end cap in with the motor running you could see the TORQUE curve on the monitor screen go UP. (they stopped when the curve peaked) PEACE RIDE SAFE

 

Border, check out this video.

 

THANK YOU...I'm not an engineer or a mechanic but the way it was once explained to me is: you want as much of an efficient/complete burn of the fuel as possible and that the right amount of back pressure helps....especially in the LOW to MIDRANGE rpms which is where the money is with V-twins...case in point I went back to my stock headers and a RS-3 SS Yoshimura slip-on for my lil' ol' ROAD WARRIOR and found an improvement in the MIDRANGE over the V&H Big Radius that my son had put on the bike (V&H makes a fine product). HOWEVER I found the extra midrange, not to mention the better lean angles reeleee helped through the (I'm a backroad junky) corners. THANKS AGAIN for the video link...PEACE RIDE SAFE