The Yamaha Road Star Warrior Forum

There are several threads out there describing different approaches to modifying the stock Warrior exhaust, but I haven't seen it done quite like this before. The procedure outlined below also works well for those of us who don't have access to a plasma torch.

Tools needed:
- Dremel with metal cut-off wheels (at least 3)
- 2-1/8" metal hole saw
- 1" metal hole saw
- 18" drill bit extension
- Electric drill

This mod consists of two phases (to avoid confusion with Frankenstein's "stages"). The phases can be done in either order, but I prefer the order I've outlined below. I've done it both ways, and Phase 2 on its own doesn't increase the sound significantly.

I should also mention that I don't have dyno comparisons and there was so much swapping between stock and modified pipes as well as a Cobra slip-on that I didn't notice a significant change in horsepower one way or the other.

Phase 1:
This phase can be done with the silencer on the bike, but I'd recommend removing it to improve accessibility. Remove the aluminum cap from the outlet of the silencer. Slide the Dremel as far into the tailpipe as you can reach (~2-1/2") and cut the pipe off from the inside out. Once this is done, Use the 2-1/8" hole saw to cut the tailpipe out of the back of the silencer. The hole saw should just fit over the ~3/4" of tailpipe that extends out of the back of the silencer. Remove the cut off tailpipe section and take her for a spin.

Using the tools and methods above leaves nice, clean edges that look professional and almost factory.

The result is a mellow rumble as opposed to the stock wheeze. The drawback is that there is an awful lot of pumping air noise when coasting with the throttle closed.

Phase 2:
This time you'll have to remove the silencer from the bike. Remove the aluminum cap from the outlet of the silencer. Install the 1" hole saw on the extension. Drill as many holes as you can from the front and the back of the pipe. If you look in the silencer inlet and the outlet (which you cut off in the previous phase) you'll see a flat piece of sheet metal which separates the 1st and 2nd silencer chambers. I was able to make 5 holes in this partition. Be sure to remove the slugs you've created during this step. You don't want them rattling around in there.

This bit of surgery isn't as slick as Phase 1, but it can't be seen unless you look inside the silencer with a flashlight.

The resulting sound is more of a low growl, quite a bit louder than Phase 1 alone. Also, the pumped air noise all but disappears. It's just the sound I was looking for. Not nearly as cool as the Big Shots I used to have, but I get along with the neighbors a lot better now.

If you give this a try, let me know how it turns out.

Added some photos. Most of the mods are internal so there isn't much to see from the outside. Major difference is that the tailpipe doesn't protrude though the end cap. You might want to have a muffler shop weld a tailpipe to the outlet for aesthetics sake, but I'm happy with it the way it is.[]

Insert Image:

22.46 KB

Insert Image:

22.89 KB

Insert Image:

23.03 KB

[8D]That is very impressive for it's simplicity and apparent ease of execution! (and well written too!) I'd like to hear the results, and a picture or video would be great. That a mod I'd like to try on a spare can.

Nicely done, pics???

I'll try to get some pictures posted later today. Not much to see since most of the mods are internal. The only noticable change is that the tailpipe doesn't protrude through the aluminum cap.

twerth,

is that my old can? im sure glad that you were able to use it.

bedivere

Hey bedivere66,
It sure is. I fried my original silencer's chrome with a torch, so I tore into the one you sent me. I ended up with the sound I was looking for and couldn't be happier. I owe you one.

anyone that has a spare can: you can use the trim ring & chrome cover off the front of it to cover your freshly modded tailpipe. It will allow you to get the full benefit of the mod instead of still forcing everything out the tiny hole in the stock trim ring. Plus it gives the water heater a nice symmetrical look IMHO.
just my two cents. Everyone, riders & cagers, always comment on how good Thor sounds compared to most v-twins.

I just did the phase 1 part of this mod. It sounds better than stock, on decel it sounds like a semi w/ a jake brake. Plan on doing the rest of the mod in the next couple of days. The '05 muffler may be a little different than the '02 because I don't see how there is enough room to make five holes in the baffle wall as stated for phase 2. It should hold me over until I can get some rineharts this winter.

You're right doc. There's a lot of extra noise on decel with the phase 1 mod only. Phase 2 makes a world of difference. I think you'll be pleased.

As I mentioned in my first post in this string, I've done this mod twice and was able to find room for 5 holes both times. I was able to drill 3 from the front and two from the back. To make things easier, don't drill your first hole in the middle. Try to drill off to one side of the inlet pipe, and then to the other side. Then you should have room for the third in between. The tail pipe is offset from the inlet, so you'll be able to drill in a different location on the baffle for the last two.

Good luck []

Thanks for the info. That gives me a better idea of how to do it. I might get to it tomorrow or Tues. I'll let you guys now how it turns out. Did you have to adjust your ecu to compensate for the extra airflow?

doc,
I have a PCIII and I'm still running the stock map. It seems to run fine with no increase in backfiring or other annoying side effects.

I also have a Cobra slip-on (for sale), and I may be incorrect, but I understand it can/should be run with the stock map. That's why I didn't get to concerned about making adjustments when I modified the stock pipe.

I put the rest of the holes in the baffles this morning and took a 30 mile ride. The sound is good, and its not nearly as loud on decel. It does pop occasionaly on decel, but its usually just one slight pop, I don't think its really enough to worry about. I did get five holes in the baffle but mine went two in the front, and three from the outlet side. I also used a 1 1/8" hole saw because that is what my uncle had. Overall the sound is alot better than stock and it should keep me happy until I can get those rineharts. I also started and revved it a little with just the header pipe, man is that thing loud.

Tried Phase one yesterday, Haven't taken it out on the road yet, but there was a significant sound increase when sitting at idle, will probably do phase 2 in a couple of weeks if I want more sound.
Great mod only cost me the tools I needed.

AD

Phase 2 will increase the sound level a little, but more importantly, it greatly improves sound quality. I'd recommend doing it as soon as you get a chance.

Let me know what you think.

I did a variation of this to my stock can. I was pleased with the overall sound. It is a little louder at idle but significantly louder when on the gas.

Instead of cutting the pipe I completely removed it. I removed the last baffle plate to the flange that the alu. cover is attached to. I wiggled the pipe until the welds broke that attach the pipe to the second baffle plate. Once the welds are broken the hole must be enlarged to allow the pipe to be removed. I did this with a 12" piece of 3/8 rod sharpened to a chisel edge, hammered around the pipe then the pipe slipped right out.

I also drilled 6 - 1" holes into the second baffle plate.