Chicago-Spike
11-21-2008, 02:10 PM
Drilling Your Stock Pipes (Clayton Root)
Drilling your stock pipes
Before you spend a lot of cash, might I suggest you try drilling. I did mine last Saturday and think I've completed the job tonight. It is incredibly DEEP, like a Big Block V8. In fact, I went too far and it became so deep and mellow, I had to plug a couple holes to add a little bite. I had carried out the same treatment on my Suzuki Volusia, which also has Fat Pipes, and achieved what for me was the best sound possible. Loud enough and pleasant enough for me on the bike without unduly pissing off the folk who don't care for motorcycles at all. I may be one of those rare motorcyclists who actually believes other people have rights too. I know I for one get ticked by those Rice Rockets with a 1,000 watts and 10 sub-woofers in the trunk so I try to respect the neighborhood a little. On both the Volusia and the VTX, I've had SO many positive comments at stoplights by motorists. Also, on the Volusia, I've had two acquaintances who'd opted for aftermarket pipes and hated them. When they heard mine, both commented that this was exactly what they were looking for. What's to lose but about $25 for drill bits and taps if you're already prepared to lay out the big bucks for aftermarket pipes anyway. Give it a shot. You may be very pleasantly surprised.
There is science to this process or the result will be a failure. Too few holes or too small holes will give you a tinny sound. 3/8" is too small to let the lower frequencies escape. Although there doesn't seem to be much of a difference between 3/8" and 1/2", the surface area difference is substantial.
You will need to work through at least 3 drill bit sizes or you're unlikely to end up with round holes. Since smaller drill bits are generally shorter, I had to buy a 6" long 1/8" 135 degree pilot bit to avoid scraping the chrome outer surface with the drill chuck. This bit worked well and didn't walk around much when trying to begin a new hole. Because of the tapered end of the exhaust pipe, center punching first is a challenge, especially at the top. My final drill bit of choice is 15/32" rather than 1/2". This can be followed with a 1/2" National Fine Tap so that fine threaded 1/2" bolts can be screwed in tightly to give you a route back to stock or allow you to custom tune the sound. I've found on my VTX that Black Allen Head bolts don't even look bad. If you don't jump ahead and overdo it like I did, you won't even need to thread any holes. That 1/2" tap was the most expensive item at $15. The 6" long 1/8" bit was $4 and I forget how much the 15/32" bit with the 3/8" chuck size cost as I had it left over from my Volusia work.
SO, this was my process. When you look inside the end of the pipe, the black plate has some notches on it. Starting on the bottom of the pipes, I centered a hole on each of these threenotches.
http://www.vtxoa.com/images/Pipe1.bmp
Went for a ride. Sounded like *****! This is when you really start to get worried but don't give up yet. Came back and drilled two more holes centering each of them between the center one and the outside two. So now I have a half circle of 5 holes looking something like a smile at the bottom of the black plate in each pipe. Went for another longer ride with my 23 year old on board. "It's awesome" says he. "It's not" says me, "but it's getting closer". Five holes was getting pretty deep and that Single Crankpin Character was beginning to be unleashed but there was a bit of a higher pitched poppiness to the sound. After our ride, I drilled a 6th hole up around the 2 o'clock position. The look is no longer symmetrical but its hard to see up in there anyway unless you're crouched right down. Went for another ride. "This is getting pretty close to what I want" says I. I came back home and figured what the heck. Eight holes sounded good on the Volusia (its a much easier job to form a perfectly concentric ring because their backplates don't have all these stupid notches) so let's try 9 holes on the VTX. Three more holes went in the top of each backplate at approximately 11, 12, and 1 o'clock. Go for another test ride. Man this thing is REALLY deep now. Now it's time to reduce the idle speed, oh yeah, lower, lower, no oil pressure light yet, lower, oops, can't blip the throttle without stalling, back up a little. SWEET! Let's take her out on the highway. At least I can now hear the exhaust at 65 mph without a windshield. BUT, it's a constant purr and I'm having a hard time distinguishing the separate firing pulses of the two cylinders. I could hear them with 6 holes. Time to experiment. Got out the Tap, threaded, and plugged the bottom hole with a 1/2" bolt. Yeah, that added just a little bite. Took the screw out and plugged the top hole instead. Nothing much too speak of. O.K. But what if I plug both the bottom hole which made a difference as well as the top hole. That will increase the velocity of gases through the remaining 7 holes and should sharpen the tone a bit more. Time for another test ride. Yeah baby, yeah! It's still got a very DEEP rumble at idle with enough edge under load to retain that wonderful Single Crankpin burble. It sounds especially sweet when pulling away from a stop. Actual volume is definitely a step up from stock but is not obnoxious at all. My wife and son love it now. This was one case where jumping ahead of myself cost me some time and aggravation but it was a good learning experience. There will be NO aftermarket pipes in my future for my VTX. For those who absolutely have to have more sound, I've heard a 12" drill bit through the 2nd plate will give it more bite but think that will also introduce some frequencies I don't care to hear and there's no easy way back. As it stands now, I can put my VTX back to absolutely stock exhaust sound with the purchase of an additional fourteen 1/2" bolts.
At this point, the only bikes I've heard that I like better are the Police Spec Harleys and the Polaris Victories. For double the money of my VTX 1300 Retro, I'm not about to go there and put up with their other shortcomings just to satisfy my lust for sound quality.
Here are the tools used:
http://www.vtxoa.com/images/pipe2.bmp
Clayton
Last update: 2004-12-17 12:47
Author: Ceetro
Drilling your stock pipes
Before you spend a lot of cash, might I suggest you try drilling. I did mine last Saturday and think I've completed the job tonight. It is incredibly DEEP, like a Big Block V8. In fact, I went too far and it became so deep and mellow, I had to plug a couple holes to add a little bite. I had carried out the same treatment on my Suzuki Volusia, which also has Fat Pipes, and achieved what for me was the best sound possible. Loud enough and pleasant enough for me on the bike without unduly pissing off the folk who don't care for motorcycles at all. I may be one of those rare motorcyclists who actually believes other people have rights too. I know I for one get ticked by those Rice Rockets with a 1,000 watts and 10 sub-woofers in the trunk so I try to respect the neighborhood a little. On both the Volusia and the VTX, I've had SO many positive comments at stoplights by motorists. Also, on the Volusia, I've had two acquaintances who'd opted for aftermarket pipes and hated them. When they heard mine, both commented that this was exactly what they were looking for. What's to lose but about $25 for drill bits and taps if you're already prepared to lay out the big bucks for aftermarket pipes anyway. Give it a shot. You may be very pleasantly surprised.
There is science to this process or the result will be a failure. Too few holes or too small holes will give you a tinny sound. 3/8" is too small to let the lower frequencies escape. Although there doesn't seem to be much of a difference between 3/8" and 1/2", the surface area difference is substantial.
You will need to work through at least 3 drill bit sizes or you're unlikely to end up with round holes. Since smaller drill bits are generally shorter, I had to buy a 6" long 1/8" 135 degree pilot bit to avoid scraping the chrome outer surface with the drill chuck. This bit worked well and didn't walk around much when trying to begin a new hole. Because of the tapered end of the exhaust pipe, center punching first is a challenge, especially at the top. My final drill bit of choice is 15/32" rather than 1/2". This can be followed with a 1/2" National Fine Tap so that fine threaded 1/2" bolts can be screwed in tightly to give you a route back to stock or allow you to custom tune the sound. I've found on my VTX that Black Allen Head bolts don't even look bad. If you don't jump ahead and overdo it like I did, you won't even need to thread any holes. That 1/2" tap was the most expensive item at $15. The 6" long 1/8" bit was $4 and I forget how much the 15/32" bit with the 3/8" chuck size cost as I had it left over from my Volusia work.
SO, this was my process. When you look inside the end of the pipe, the black plate has some notches on it. Starting on the bottom of the pipes, I centered a hole on each of these threenotches.
http://www.vtxoa.com/images/Pipe1.bmp
Went for a ride. Sounded like *****! This is when you really start to get worried but don't give up yet. Came back and drilled two more holes centering each of them between the center one and the outside two. So now I have a half circle of 5 holes looking something like a smile at the bottom of the black plate in each pipe. Went for another longer ride with my 23 year old on board. "It's awesome" says he. "It's not" says me, "but it's getting closer". Five holes was getting pretty deep and that Single Crankpin Character was beginning to be unleashed but there was a bit of a higher pitched poppiness to the sound. After our ride, I drilled a 6th hole up around the 2 o'clock position. The look is no longer symmetrical but its hard to see up in there anyway unless you're crouched right down. Went for another ride. "This is getting pretty close to what I want" says I. I came back home and figured what the heck. Eight holes sounded good on the Volusia (its a much easier job to form a perfectly concentric ring because their backplates don't have all these stupid notches) so let's try 9 holes on the VTX. Three more holes went in the top of each backplate at approximately 11, 12, and 1 o'clock. Go for another test ride. Man this thing is REALLY deep now. Now it's time to reduce the idle speed, oh yeah, lower, lower, no oil pressure light yet, lower, oops, can't blip the throttle without stalling, back up a little. SWEET! Let's take her out on the highway. At least I can now hear the exhaust at 65 mph without a windshield. BUT, it's a constant purr and I'm having a hard time distinguishing the separate firing pulses of the two cylinders. I could hear them with 6 holes. Time to experiment. Got out the Tap, threaded, and plugged the bottom hole with a 1/2" bolt. Yeah, that added just a little bite. Took the screw out and plugged the top hole instead. Nothing much too speak of. O.K. But what if I plug both the bottom hole which made a difference as well as the top hole. That will increase the velocity of gases through the remaining 7 holes and should sharpen the tone a bit more. Time for another test ride. Yeah baby, yeah! It's still got a very DEEP rumble at idle with enough edge under load to retain that wonderful Single Crankpin burble. It sounds especially sweet when pulling away from a stop. Actual volume is definitely a step up from stock but is not obnoxious at all. My wife and son love it now. This was one case where jumping ahead of myself cost me some time and aggravation but it was a good learning experience. There will be NO aftermarket pipes in my future for my VTX. For those who absolutely have to have more sound, I've heard a 12" drill bit through the 2nd plate will give it more bite but think that will also introduce some frequencies I don't care to hear and there's no easy way back. As it stands now, I can put my VTX back to absolutely stock exhaust sound with the purchase of an additional fourteen 1/2" bolts.
At this point, the only bikes I've heard that I like better are the Police Spec Harleys and the Polaris Victories. For double the money of my VTX 1300 Retro, I'm not about to go there and put up with their other shortcomings just to satisfy my lust for sound quality.
Here are the tools used:
http://www.vtxoa.com/images/pipe2.bmp
Clayton
Last update: 2004-12-17 12:47
Author: Ceetro