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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 ¼” 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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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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Discussion Starter #3

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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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Discussion Starter #5
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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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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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?




Sent from my Motorcycle iPhone app
 

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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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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 :clap:
 

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I love the sound Roy I was thinking of doing mine too but mentioned it to my dealer and he said he wasn't sure but it might give the BMW rep. a way out of a waranty repair should I have a major problem. I realy can't see how since most dealers sell and install the akv.s and they are just about straight thru. What do you think? Tom
 

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I love the sound Roy I was thinking of doing mine too but mentioned it to my dealer and he said he wasn't sure but it might give the BMW rep. a way out of a waranty repair should I have a major problem. I realy can't see how since most dealers sell and install the akv.s and they are just about straight thru. What do you think? Tom
It would certainly nullify the warranty on the pipes. Beyond that, somebody would have to show how it affected whatever it was that wasn't working. My understanding is that just because the end user modifies the vehicle doesn't mean that the warranty on the vehicle is voided. If the modification causes the problem then, of course, the manufacturer has no liability for that problem. It would seem to me to be a bit farfetched to claim that adding 4 1/4" holes could hurt anything when the GT cans come stock with additional holes.

I also tend to think it would be unlikely that anyone would notice anyway.

Of course all of that is just my opinion. It obviously doesn't concern me in the slightest or I wouldn't have done it.
 

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Another Video

Since I made that video, I did another one where I wasn't so restricted due to traffic. In this video you get a sense for what the mod sounds like when wound out a bit. It's a long video, so if you just want to hear the sound at 125-135mph, jump to 2:10 and 11:40. :gm

Just keep in mind that like the previous video, the mic is placed such there is zero wind noise and 100% engine noise. You will not hear this sound when riding at speed any more than you would hear all the transmission clunks that sound so loud in the video with the mic placement.

 

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Nice video.

Was wondering what 120 looks like on the speedo. Only saw it once on the GPS after the fact. Can't bring my eyes off the road at that speed.
 

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Hey Roy,

I was just down in the Blackwater yesterday with a couple of guys. That's a fun ride down there. We did a loop up north to Massey and then back down through Queen Anne before we went down the the bottom of the Blackwater and back - about 250 miles.

Can I ask where you've got the mic? I've experimented with a few place but not sure I've found the right set up yet.
 

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Discussion Starter #16
Hey Roy,

I was just down in the Blackwater yesterday with a couple of guys. That's a fun ride down there. We did a loop up north to Massey and then back down through Queen Anne before we went down the the bottom of the Blackwater and back - about 250 miles.

Can I ask where you've got the mic? I've experimented with a few place but not sure I've found the right set up yet.
Hey Wes. On that video the mic was clipped to the license plate. Yep, for local rides that one and a loop up at Catoctin Mountain ( Camp David for the non-locals) are my favs.

I should add that for really, really local for you and me, Governor Bridge Road between Riva Road and 301 in Bowie is a quick, fun ride.

Sent from my iPad using Motorcycle
 

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I should add that for really, really local for you and me, Governor Bridge Road between Riva Road and 301 in Bowie is a quick, fun ride.
Sssshhhh.... we're not talking about those publicly :k16:
 
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