Muffler drilling FAQ

Hi,

I found the tutorial copied below, to open yamaha mufflers. Our XJ pipes are build like this as well? Can anyone share his experience on this method? I want to keep my stock megaphones, because I like their looks very much. But prefer a bit louder sound. Or does anyone know an aftermarket open muffler with the same dimensions? See the last picture for the model I have.


The Stages of Pipe Drilling

Drilling the stock pipes is the most popular modification among ‘Star owners. The stock pipes are very restrictive and quiet, primarily in order to meet the strict guidelines in some of the states that the bikes are sold. Of course, we all want sound and performance. Aside from investing several hundred dollars in a quality set of aftermarket pipes, this is the most effective way to get there. “Staging” will also allow you the flexibility to tune the sound to your liking.

Below are the stages and how they are done:



Stage 1

Introduction

Stage 1 involves removing the cone from the back of the muffler, or “slip-on” portion of the exhaust system. This exposes the plate that holds the final exhaust tube in place. holes in this plate frees up the system and significantly changes the tone and volume. This is the idea behind Stage 1.

It is best to perform the following procedures with the muffler set removed from the header pipe and taken off of the bike.

1. Use a ‘Dremmel’ type tool to cut the weld that holds the tailpipe cone to the exhaust pipe. This will completely free the cone. The cone can now be removed from the muffler. This can be tricky. If you like, tap a sheet metal screw into the surface of the cone, which gives you a grab point. Once removed, the cone is useless, so looks aren’t important, however you will want to minimize the damage to the center pipe, because with stages 1 & 2 the pipe remains where it is.

2. Once the cone is removed, use a punch to mark where your holes will go. Start at 12:00/3:00/6:00/9:00 and drill ½” holes.

3. Reinstall the mufflers and start the bike. If you are happy, you are done. Most will probably want to drill additional holes at the mid-point between the holes you just drilled, giving you a total of 8 holes in the baffle plate. This tends to reduce the “fluffing” sound that only 4 holes will give you




Stage 2

Introduction

Stage 2, as this is generally referred to, is the process of drilling “blindly” into the lower baffle plate. This is accomplished using a long drill bit and drilling through the holes that you drilled in the first baffle plate and into the second baffle plate. The effect is a slightly louder exhaust.

Again, it is recommended that you remove the mufflers from the head pipe, and take them off the bike.

1. Using an 18” long drill bit, enter the holes that you drilled for Stage 1. Find the second baffle plate and drill random holes in the plate.

*Note... The effect that stage 2 has is minimal. Generally speaking, if Stage 1 has grown old, or if it does not provide the desired sound, you should skip Stage 2 and go to the Stage 3 modification.



Stage 3

Introduction

The Stage 3 modification seems to be the most popular. In fact I have done 3 sets of Stage 3 pipes without ever stopping at Stage 1 or 2. The process essentially defeats the 1st and 2nd baffle chambers and uses only reduction and re-direction as the means of baffling the sound. The modification is reasonably simple and once Stage 1 is complete, you’re half way there!

1. Using a 1” hole saw, drill out the first baffle plate in an overlapping fashion, essentially eliminating the baffle plate entirely. You will leave jagged edges, and a center pipe that is no longer supported.
2. Using a hammer and chisel (or comparable tool) push the jagged edges that are attached to the center pipe back out of the way.
3. Using the same method, push the jagged edges back that are around the outside edge (attached to the inside wall of the exhaust) of the muffler. You can also grind or cut them off, although this is time consuming and the net effect is the same.
4. Insert something sturdy into the center pipe. Whatever it is, it should fit inside the pipe tightly, and give you a firm area to grip. You will then twist and turn the center pipe, using as much force as possible, until you feel the weld in the bottom of the pipe give way. Continue working the pipe until it comes completely out of the muffler.
5. All that is left is to clean up the inside of the pipe by working with the leftover edges and using some flat black spray paint.

It is strongly recommended that you re-jet the carburetor at Stage 3. A Dyno-Jet kit using a 165 to 170 main should be sufficient. You do not want to run too lean and because the stock setup tends to run lean already, allowing exhaust to exit easier tends to exaggerate the condition.

The end result will be a better running, better sounding bike, no matter which stage you choose.


Illustrations stage 3










SOURCE: http://roadstarclinic.com/content/view/50/105/


My bike

 

I don't know about drilling the pipes, but I'd like to see some more pictures of your bike! That's an XJ700, yes?

 

Based on the trim, it looks like it might even be an "X."

That being the case, start drilling holes in your exhaust system and you're gonna break "the magic."

Actually, as soon as you start screwing around trying to out engineer Yamaha on an XJ, be it aircooled or watercooled, you'll quickly discover that Yamaha had it right and overall performance and rideability will suffer. And a stocker will (quietly) leave it in the dust.

 

It's an aircooled xj700s, with shorter shocks and the 5-valve carb covers of the 'X', just for the looks. Once the bike is finished, I'll dedicate a topic to it. These are the only pictures I currently have.

I'm buying a second set of mufflers, to be able to go back to the original setup...

 

Not the right engine for and X......the fins are visible. I think there's some 'trimwork' added on. Actually, that one kind of appeals to me......

 

Haha.... just saw his reply
Dave

 

Thats what I figured. I lurked through some of your other posts and am wondering why you want to change the tank and bars? I think, from the angles you have presented, that the lines of the bike look really good. In fact, I think with the chopped fender and seat you even found a way to make the stock megaphones looks really good. Would love to see how you cut the rear off of the frame.

 

Bigshankhank:
Initially I wanted narrow apes, an oldskool look. But that just didn't match the angled risers of this bike. And while fabricating the seat, it became more of a cruiser look. Because I couldn't find which other triple trees would fit, I decided to go for these bars. So this style arose organically. I later read that the triple tree of a virago xv fits. If I find a real 'X' once, I may still continue this idea.

From these angles and from a front view, the lines are great indeed. From the side, the bike isn't compact enough or too much upwards. That's also why the mirrors aren't mounted yet. They will be of a hanging type, below the steering bar. A little counterweight could be created through raising the highest point of the seat by 2-3". I'm thinking about lowering the fork 1". Anyways, I'm pretty confident indeed. Hopefully it's finished next week so I can supply you with pictures. I'm not tall by the way, then I couldn't ride this bike comfortable...

 

Cool, I look forward to seeing more of it. It is giving me inspiration to suck it up and get back to work on my engine in my hot-as-hell garage.

 

Go with bar-end mirrors.

They really "lower the look" of the front end; and honestly change the whole appearance of the bike. I have two 550 Secas, one with stock mirrors and one with bar-end mirrors; and although they have the SAME (aftermarket) handlebar on them, the bike with the bar-end mirrors appears to have lower bars.

 

I did out on bar end mirrors. But I did go with a straight drag bar. Maybe I need to go with a style like yours

 

nice bike!!
but w.t.f. is that, in the cage
stu 8O

 

Bensalf: An African Boerboel in its doghouse, for the times I can't let it run around...

 

I just saw a 1/2 dog, 1/2 hyena on t.v. at a "ugliest dog show". Bet he'd be a scary sob to have in the house at night or whenever the hyena side kicks in. WTF!

Gary

 

Well...I bought an old rusty muffler and drilled the rivets to take off the chrome endcap. This doesn't enable you to take off a cone, as in the illustration.

The actual endcap is seamed with the megaphone tube.
The easiest way to drill the muffler would be as in the picture below, or just one hole through the partition/panel that you're seeing when you watch in the tube from either the end or the side of the collector box. Unfortunately I don't succeed taking a picture of these, too dark in the tubes.

I'm doubting what's the best option. Also thinking about cutting it in half lengthwise, to see how it's really constucted. But as these mufflers are rarer than I thought here in the Netherlands, I'm probably won't do...

 

In the meantime anyone else perhaps gained some insights into this? My project was on hold for a couple years but am planning to proceed now!