Discussion in 'Sportster Models' started by Dustinthewind, Jan 27, 2011.

  1. Dustinthewind

    Dustinthewind Member

    I am interested on thoughts on either drilling holes in the baffles on a 2008 1200R EFI. any problems that one can experience .What about back pressure. Someone mentioned removing them. I don't know,I don't want to do anything that will wreck the engine. I would appreciate hearing from anyone who has done this mod and is it worth it?
    best regards!!
  2. Jack Klarich

    Jack Klarich Expert Member

    Better to put on some slip ons, you wont like the sound after drilling out the baffles
  3. geezer

    geezer Senior Member Contributor

    I did it on my Heritage for 2 reasons, the aftermarket pipes i put on sounded terrible and I liked the look of the stock mufflers. I had it re-tuned with my TTS tuner. Runs and sounds great now and still looks like stock.
  4. Iceman24

    Iceman24 Well-Known Member

    Dustinthewind; what are you trying to achieve (sound, performance, etc.)? Advice/responses will differ, based on your reasoning...
  5. bikecurious

    bikecurious Member

    I cut my SEII slipons in half also cutting the baffles in half then re welded them outward. My buddy had them on his EFI sporty for a bit and they work great on both.... very loud.
    back pressure shouldn't be an issue because you have that lower crossover.[​IMG]
  6. ron1978

    ron1978 Active Member

    just installed a set of big city thunder monsters, there great!!! deep and loud! easy to install, i cut my stock v&h baffles in half, an d it didn't give what i wanted,
  7. Dustinthewind

    Dustinthewind Member

    Hi all.
    I used the Gronk mod from another forum to modify the mufflers. 1 3/4 " hole saw ,drilled the end and pulled out the baffles. Used a drill press and with a 1/4 " bit I enlarged the baffle holes as well as adding two more rows at the outlet end of the baffle. Cleaned the baffle with a small threaded rod to get rid of any fragments still hanging on. Then I took them to a muffler shop and had them mig weld the baffles in once again. (taking care to use a wet rag to keep the muffler ends cool,no blueing. total cost about $40.00 plus breakfast. You can here the sound on youtube. Just click on Harley Sportster with Gronk mod. It gives me a nice deep rumble without being too loud. At sixty years old I prefer the deeper rumble. The mod itself took me about 1 1/2 hrs. By the way Don't knock the inner cap out of the baffles . It's all stock except for the resized holes, and looks completely stock on the motorcycle. I like the look of the stock mufflers.
    Best Regards!