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WorkShop > Yankee Intruder > Pipes

The Yankee Intruder
by; C. Gustave Sandberg (Sandy)
Sandy@YankeeCruisah.com

Yankee Pipes
There is quite alot of personal preference as to what is the "Best" sound.
In keeping whith the Yankee tradition, lets explore a couple of ways to improve the sound, and lets hope get some more performance.
The Stock mufflers, have a 3 baffle system, (now I'm talking about the stock Intruder 1400 pipes, but the stock 800, and the Cobra slash cuts are very similar design.) If you want "LOUD", then remove the baffles, and re-tune for it, and you'll get what 'Gunner' calls the sound of "A Norton on Steroids". I you want more rumble, and a louder note with little or no re-tuning, with a good level of adjustability then you can do various levels of 'drill the pipes'.
Either way you go, remember, that the cost of doing it is close to '0', so it's not like you're out $300 for a sound that "well ... it's ok". You can get the sound of the Cobra Slash Cuts, with a simple drill, or the sound of "A Norton on Steriods" with a drill and a slide hammer.
Now lets go on.

8/99
Well ... to help in the decision, I have recorded the three variations in .wav files.
I feel, the stock is too soft and quiet, the drilled is louder and has more bottom (rumble),
while the de-baffled (gutted) pipes were definatly louder.
Lets give a listen to my 1400, in various stages. (BTW the carbs have been adjusted but not jetted).
1400 Stock pipes
1400 Drilled Stock pipes
1400 de-Baffled Stock pipes
And now for something a little different
These were recorded at 10 feet directly behind the bike, unfortunatly the AGC (Automatic Gain Control) on my recorder wouldn't let the different sound-levels be noticed.
I might go back and re-record them slightly off axis, since most people will hear them from the side,
with a non-AGC recorder. I could also measure the level on a dB meter. stay tuned!

Drill the Baffles

From: "Dennis Dibala" <cts@phoenix.net>

italics are my comments / additions

The stock muffler contains three baffle plates. I started with less than 1/2" holes so a 1/2" bolt could be screwed in to return the sound to 'stock' four holes in just the rear (outer) baffle. This made the sound louder and a little deeper. I thought I could get the sound a little deeper yet by drilling four holes in the next baffle forward. By going through the four holes I had previously drilled, I drilled four 3/8-inch holes in the next baffle. This made the sound a little louder and a little deeper yet; however, if you are still running the stock jetting, you may experience a little popping when you chop the throttle while riding (although probably not any more than with after market mufflers). See the Yankee jet kit (below) to help eliminate the popping.

I then tried drilling a 1/2-inch hole in the innermost baffle. This was a mistake, as the bike didn't run smoothly and it popped excessively. I ended up having to go through the main exhaust outlet and welding up this last hole I drilled.

Try drilling holes in the outermost baffle first, if this is not as loud as you want then drill the next baffle in through the holes you previously drilled. Just remember that if you drill in the second baffle in, you may experience a lean condition. DO NOT DRILL ANY HOLES IN THE INNERMOST BAFFLE. Learn from my mistake. Note: when I refer to the innermost baffle, you can see this by shinning a light through the stock outlet (hole).

I have since installed a set of the Cobra slip-ons using the system with a muffler on each side like stock. I am pleased with these, but I don't think the bike runs any better than with the stock mufflers drilled. The sound isn't really that much different either.

Dennis

I drilled the outer baffle, and liked what I heard so much I went and drilled the second baffle, this did produce the popping sound, so I went and installed the Yankee Jet Kit.
Sandy

Remove the Baffles

The baffles are held in by four (4) (3 on the 800) rivits, that can be seen from the back of the pipes. Drill these rivits out using the electric drill ,and an appropriate sized bit. To remove the baffles you use a 'dent puller' or slide hammer.
You can make a slide hammer like RB did, as I will quote from his letter.
I made something like a small slide hammer. It was a 10" long carriage bolt and a short piece of 1" diameter round stock, and drilled out to slide on the bolts. I put 2 nuts on the bolt. The bolt head just fit inside the exhaust port and the flat side of the bolt then hooked on the inside ridge of the baffle. Sliding the block hard against the nuts backed the baffle and the rear plate out.
He goes on the now tell you NOT to remove the baffles, and drill the plates instead, but we're going to let you decide that. If you want more info, you can surf over to http://www.aros.net/~burnin as he also has a description with pictures of what they did to a Marauder exhaust (similar to the 800 Intruder).

Conclusion

Well there are no clear or simple conclusions, everyone has their own opinions and desires.
Lets just say that here are a couple of ways to get a better note from you ride. And by doing it 'on the cheap', you're not out any money, and maybe have improved the ride.
I'll finish qouteing RB when he says,
This cheap fix is better than buying after market pipes because the sound is great, and you can adjust the volume at will.
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