Modified GTL Exhaust Note - BMW K1600 Forum : BMW K1600 GT and GTL Forums
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post #1 of 140 Old 05-31-2012, 09:19 PM Thread Starter
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Modified GTL Exhaust Note

I contemplated figuring out a way to drill the extra holes in the sides of the plugged chambers of my GTL cans to turn them into GT cans. But the only way I could figure to do it was to cut the end caps off, do the drilling and weld them back together. It could be done, but what a chore.

I figured that BMW chose to put the holes in the sides of the plugs because they got better sound that way, so that had prevented me from drilling a hole at the end of the plugs, which would be relatively simple. But a couple of weeks back I was standing next to the bike in the garage with a drill in my hand with a long bit and well...

I drilled a 1/4" hole in the end of each of the sealed plugs. Had to aim the bit slightly "up" to miss the thickest part of the crimp, but it was pretty easy. I used a well greased bit to recover as much of the shavings as possible.

The result was just a bit louder but much throatier sound. I need to get it next to a GT to see how close the notes are.

I just got an external mic for my Hero2 camera today, so I thought I would share the results of the modification here for those who want to know what it would sound like before they start drilling their expensive machines.

I clipped the mic to the license plate to put it out of the wind and close to the pipes. The result is a very good representation of the note, though don't get the idea it is anywhere near this loud in the cockpit. I can hear it but it is really quite subtle. If you're behind me, I'm guessing you would hear something like pretty close to what you hear in the video.

You get some examples at idle, driving through the neighborhood, accelerating and riding on the highway as I crossed the Chesapeake Bay Bridge. Unfortunately I couldn't really get into it because that section of road is watched very closely by LEO's since 9-11 because of the bridge. And since they really have nothing else to do, a lot of tickets get written here. As a side note, you'll notice that traffic on the bridge comes to a crawl at about 3:55. We find the culprit as I pass two Maryland State Troopers on their bikes in the right lane at around 5:04. Looked to me as if the guy on the left was an instructor with a student on his right. Why they decided it would be a good idea to have a training session at 15 mph on a 4.5 mile bridge, I have no idea.

Here ya go:
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post #2 of 140 Old 06-01-2012, 07:20 AM
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Thanks for the vidio Roy. It sounds great,been thinking about doing the same on my GTL. How long a bit did you use and what brand of windshield do you have and do you like it? Tom
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post #3 of 140 Old 06-01-2012, 08:37 AM Thread Starter
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Originally Posted by BIRDDOG51 View Post
Thanks for the vidio Roy. It sounds great,been thinking about doing the same on my GTL. How long a bit did you use and what brand of windshield do you have and do you like it? Tom
The bit is 11.5" long. The shield is a CalSci and I am in mad passionate love with it.

My CalSci shield love affair is detailed here: https://www.k1600forum.com/forum/bmw-...creen-wow.html
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post #4 of 140 Old 06-01-2012, 09:54 AM
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Mufflers

There was a post a few weeks ago from a person who devised some sort of hole saw to open up the closed tubes at the rear of the mufflers. From his description, it sounded like it worked well. Do a search.
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post #5 of 140 Old 06-01-2012, 10:14 AM Thread Starter
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There was a post a few weeks ago from a person who devised some sort of hole saw to open up the closed tubes at the rear of the mufflers. From his description, it sounded like it worked well. Do a search.
I had seen that thread also, which was very helpful because I could see how the end of the plug was crimped. That gave me some clues on how to drill. But just drilling a 4 1/4" holes was much easier than totally removing the plugs and I am pleased enough with the results. I really didn't want to make the thing much louder.
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post #6 of 140 Old 06-01-2012, 10:52 AM
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Hey Roy,

Want to meet up and compare my stock GT exhaust with yours? There might be a few of us meeting up at Bob's tomorrow then heading off to lunch.

Wes
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post #7 of 140 Old 06-01-2012, 12:32 PM Thread Starter
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Hey Roy,

Want to meet up and compare my stock GT exhaust with yours? There might be a few of us meeting up at Bob's tomorrow then heading off to lunch.

Wes
Tomorrow is a bit iffy. What time will you be at Bobs?




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post #8 of 140 Old 06-03-2012, 07:09 PM
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I did the same easy modification. Started out with a 1/4" drill bit and then followed up with a 3/8" bit.

Very nice sound, slightly louder then my friends stock GT.
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post #9 of 140 Old 09-02-2012, 02:08 AM
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Kudos to Roy for sharing. I just did this and it does make a difference.
While it's not a beautiful Remus tone, it improves stock measurably.

Thanks Roy.

Regards - Len
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post #10 of 140 Old 09-02-2012, 07:57 AM
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Am I missing the link?


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