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DIY Tutorial: Bafflectomy Honda 919...

51K views 61 replies 31 participants last post by  Dirty Birdy  
#1 ·
I'm creating this thread as a walk through for those of you that would like to perform a "Bafflectomy" on your Honda 919. It is a very straight forward and simple modification that opens the exhaust note up as well as give the rider a better "feel" for the bike due to the restrictive nature of the stock exhaust with baffles.

*BEWARE* This modification is irreversible, if you mess up, you're on your own!

To start, you're going to need several tools:

-1 1/4" Bi-Metal Hole Saw

-2 1/8" Bi-Metal Hole Saw

-Power Drill

-12mm socket

-Phillips head screwdriver

-A long 8-12" ~ 1" diameter bar or tube (for breaking the welds on the baffle)

-Vacuum/Telescoping Magnet

-A beer.


So now you have your tools, let's begin tearing the bike apart!

First off, I recommend (although not necessary) to remove the seat and tail from the bike. The seat, just remove as normal.

The tail, you must first remove two push clips located at the front of the tail section:

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Next, remove the two 12mm bolts located the the back of the tail section:

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Once these two bolts and two clips are removed, you can slowly slide the tail section from the frame of the bike. Be aware, the tail light is still connected so you will have to unclip the connectors for that.

When all is done, it should look like this:

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Next step, get your power drill out and attach the 1 1/4" hole saw:

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Using the 1 1/4" hole saw, you are going to SLOWLY drill around the exhaust at this location:

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This will be the result:

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Now, using the 2 1/8" hole saw, you will repeat the process for the outer portion of the exhaust cap. Once finished, it will look like this:

Image


Notice the "washer" that was left over? Use a small telescoping magnet or needle nose pliers and remove that:

Image


Also, clean up any metal dust created by the drilling. I used a magnet, but a shop vac with a smaller hole would work as well.

Both exhausts with "washer" piece removed:

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Next, we need to break the welds on the baffle pipe. To do this, I recommend getting a long bar or pipe and inserting it into the pipe itself. This is so you can move the pipe back and forth, softening the welds and allowing them to easily break.

I used an old pair of channel locks:

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Both pipes removed:

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The result of removing the baffle pipe and exhaust caps:

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Also, make sure to spray some high temp engine paint (black) on the section of exhaust that you drilled out, to stop any rust from forming and give a nice clean look.

With the tail section back on:

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Andddd...CONGRATULATIONS!! You just performed your first bafflectomy. You'll notice a grumble at idle, and a nice exhaust note at peak RPMs. Not too bad for a free modification!

If you have any questions, or comments feel free to PM me.

Thanks guys,

Chris
 
#5 ·
I didn't want any metal to scratch the clear/etc. I'm just very particular about that stuff.

As for painting, when you drill the larger diameter hole, what's left around the edge of the exhaust is rough and somewhat of an eye sore. I filed the edges smooth and then painted the edges to prevent any rust in the future.
 
#14 ·
moto i really appreciate the thread dude...just finished and i have to say the biggest feat wasnt breaking the welds .it was forcing the baffles outta there socket. the welds deformed the part of the baffles that were behind the weld and kept em from easily sliding out like i assumed would happen. nothing some locking vice grips and a hammer couldnt fix. badass read man. to all who plan on performing this mod i suggest two locking pliers (one to clamp to the baffle and the other to clamp to the first clamp for hammering leverage)...hammer until those restrictive shyts are out.
 
#15 ·
moto i really appreciate the thread dude...just finished and i have to say the biggest feat wasnt breaking the welds .it was forcing the baffles outta there socket. the welds deformed the part of the baffles that were behind the weld and kept em from easily sliding out like i assumed would happen.
This is the issue I ran into as well, so I'm glad it's not just me! I ended up using a long flathead screwdriver as a chisel to open up the hole a little more so I could get the baffles out. Everything else pretty much went as expected, so thanks for this guide!
 
#19 ·
Excellent write-up! I would add one thing however, when using the hole saws keep em cool and lubricated with WD-40, it not only keeps things running smoothly but also adds some cool smoke tendrils but the aromatherapy factor is AWESOME :)
 
#20 ·
Bafflectomy complete

I just finished the bafflectomy it was very easy. I bought holes saws from homedepot (milwaukee brand bi-metal) not the best but got the job done. I want to thank Moto I could not have done it without you. Wish I could buy you a beer. Thanks again.
 
#21 ·
Pre-Surgery Questions

Planning to do this mod in the coming days. Just wondering, are there any downsides? What was the design purpose for the original baffle? Is it mainly an emissions reduction thing? Also, does the bafflectomy change the air flow enough that I'm going to have to remap? Thanks for this write up! Very helpful!
 
#22 ·
The only downside for me is the rumble at highway speed. It hurts your ears! I have yoshi race exhaust (not street legal) shhhh! The debaffled cans sound very similar to the yoshi at low speeds but the air doesn't seem to exit as clean with the debaffled cans.

I would try to acquire a second set to cut up and save the oem cans for your long trips.

Just my 2 cents.
 
#23 ·
Just performed this and had a heck of a time. I too used Milwaukee hole saws and while the 1-1/4 was able to do both sides, the 2-1/8 was so dull by the second side that it wouldn't make it through. I had already been to HD twice (to get saws and then exchange the arbor because I got the wrong size) so I fought through using a 11/32 bit and making multiple holes and filing out chunks.
Once I got that done and had separated the pipe at the weld I again had to fight for a long time to get the pipe out. It was my own fault for not having vice grips. Finally got it done though, just need to clean up the edges a bit more, I didn't have it in me to file anymore. Originally thought I might forgo the cleanup with the magnet and let the exhaust clear itself while running. So glad I didn't do that, a lot of filings came out on that magnet.
Lesson learned... don't try to 'get by' with what you have, buy the right tools. (although the hole saws were all they had). Oh, and I haven't gone for a ride yet, but I like the note at idle. Thanks for the write-up!
 
#24 ·
I'm eager to get it done soon. Wonderful walk-through. One question though, when looking at the pic of the de-baffled can; why are there 3 holes where the welds break and which one does the pipe actually come from? Regardless, it doesn't change anything I was just curious. Ok... Two questions... Does anyone here regret doing theirs?
 
#26 ·
What happens is that 2 of the three holes are open so exhaust goes in and circulates around the back part of the pipe as other exhaust is exiting through the much smaller connecting pipe between that plate and back part that you remove.

And I don't regret it at all! I actually have a stock-stock exhaust that I had to put on when I was painting mine (I took off the front heat shields) and I could barely hear it, which made me a sad panda.

Here's how it sits now:

 
#29 ·
Who knew you could spend an extra hour and get another one of the mid-pipes out :laugh: ?

The last one is much deeper, I didn't have any tools to reach that far, nor did I really want to open up the exhaust that much (at least with not a Power Commander to adjust for the loss in backpressure).

PO of these pipes had cut out the outside ring on the baffles, I just had to cut the inside out and knock them out.

I did notice that they are usually only welded on the sides, exactly east and west, so like this:

|0|

| = Weld
0 = Pipe


So on the second one, rather than trying to pry it out, I just hammered with a long screwdriver against the sides and popped the welds. Hard part was then pulling it back through. Just had to pry the opening a bit to make room and them pull it out.
 

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