Dyna Fat Bob exhaust modification

[dave franklin]

I've recently purchased the new Dyna Fat Bob. The exhaust on this bike looks awesome, but the sound - well non existent! I've tried to improve this by removing the wadding wrapped around baffles, but still too quiet for my liking.

Can anyone suggest a modification that improves the sound of this bike, which has little effect on power output or removing baffles completely? I realise slip-ons may be an answer but reluctant at this point, in case a modification to original equipment will suffice.

[Monkeybrain]

As with any baffle you can drill more holes or make the existing holes bigger, this will gradually increase the volume.

[Dave_Scott]

The Fat bob has catalists in the actual ex pipe, not the silencers as is usual,

You will have to change the whole pipe,

these will be available soon, they also have the 0 2 sensors in.

[Monkeybrain]

If there is a removeable baffle I can't see why it couldn't be drilled, from what I've read it looks as if the CAT is in the power chamber area. Read this....

Fat bob - added SE street performance slip on's

[dave franklin]

Thanks Monkeybrain and Dave Scott for your great advice. Really like the look of the Screaming Eagle pipes. Cheers Dave

[Striker]

I had a go with the drill on Saturday, be warned that the 2 silencers are very different and if you drill down the center you'll need a very long bit.

For what it's worth the baffles are very very restrictive , I drilled out the center and when I put them back on they were better but only just.

I ended up buying Rush slip ons, they sound great and for £300 are well engineered.

Cheers,

Andy

[Moosehead]

Hi Andy
These rush slip ons you got, did they go straight onto the new Fatbob without new brackets etc? Have you kept the original headers fitted?

Cheers

[big-al]

Hi,

Just did this to my new fat bob.

Disconnect the battery
Take off the silencers after the cat
Drill three pop rivets out of each silencer
Remove baffles
Top baffle has one metal disc, bottom has two
(This now sounds a little bit brutal from here on)
With a sharp 3/4" wide 18" long cold chisel and holding the top baffle by hand, place the chisel down the front end of the baffle and hit it with a lump hammer, this cuts through the thin disc, repeat until the chisel goes right through. This keeps the exhaust gasses flowing without restriction after re-assembly.
Repeat this through both thin discs on the bottom baffle
Re-assemble the silencers, (I left the wadding around the baffle) and use new stainless steel rivets (I got 6 for £2.00)
Refit to the bike

I also added a new K&N air filter (Part No. HD-1499 £52.00) which is a straight replacement but the two rubber breather pipes need a bit of tweaking as they go into the filter on the opposite side, this does not interfere with the re-fitting of the chrome cover

Reconnect the battery

Now take it out for a good 40 mile ride without switching off the engine so the onboard computer re-calibrates the fuel injection system

Result is a louder (More Harley sounding) bike with significantly improved performance