To be clear, I'm waiting for an FMF Q4 that's on a long backorder and got cabin and lockdown fever. I'm not suggesting this is the new way forward, just posting some fun I've been having while waiting for my FMF. The end result of the OEM exhaust mod is the bike no longer sounds like a sewing machine - it's much throatier but still on the quiet side. I might experiment more.

The pics below pretty much describe the process:

• The first pics of the pressure gauge was just me being annal and testing (110 PSI) back pressure before and after mod. Dropped by 15 PSI.
• I used 1 1/4 hole saw that I rigged to stay centred in OEM tail pipe out. This kept it from bouncing around and making a mess.
• I also used the hole saw for making my new exhaust flange. And yes I do have a welder and I know the welds aren't great . . . I'm learning:-)
• Once the hole was drilled I did have to wiggle the small pipe back and forth till it finally broke off in side. The new larger pipe I welded in is much shorter and therefore does not close the last chamber as the OEM did.
• Sorry I forget to video sound before making mod - oh well.

Feel free to ask any questions.

 

BTW - having done the MCM, DJ stage 2, KDX Snorkel, Uni filter, 13t front sprocket and 43T rear makes a big difference in response (note I'm avoiding the word "huge").

Here's a look at the "finished" product. Also another short sound recording outside (and yes its COLD here). Still really looking forward to when the FMF finally arrives . . . if ever.

 

Not that anyone could tell by looking at it, but will the modification still meet the spark arrestor requirements?

 

Great question - my assumption is that the mods have negatively impacted the spark arresting performance. I did put an enlarged piece of pipe on for looks and to help reduce the risk of sparks but fully aware that this would likely not pass legal or engineering scrutiny. I am still planning on putting a Q4 on as soon as it arrives.

 

Once your Q4 comes in, you are ready for the "huge" ! ( But you'll have to ditch the airbox lid and re-do the CVK setup to get the Huge..)

 

Thanks again Klxster. I've started looking into getting the PowerBomb header too and yes I will redo the CVK setup if I go that root along with lidless. So glad that it's all clearly explained and detailed in this forum. Makes navigating choices and outcomes so much easier! BTW I used to live in Dallas Texas years ago but have been back in the Great White North for sometime now.