Muffler discussion (Commando or otherwise)

[SomervilleXS650]

I'm considering upgrading the stock pipes and mufflers on my 1974 TX650A. I chose to keep the stock ones when I did my resto last year and just focus on riding, but I think I may opt to take on this winter project ahead of the riding season. The old headers have some rust and the mufflers have a few dents and scrapes, and both seem to be rusting out from the inside (I know the inner pipe of the headers leak).

I was very happy to see 650trader sorted out his website yamahaxs650.com issues and got his store up and running, and sounds like a lot of you guys are jumping on the 750 Big Bore kits he has. I was gonna check out his exhaust options.

What I'm considering is:
* 1.5" chrome headers. Seems no one is really doing pipe-in-pipe, so seems like single wall is the only option. And having seen lots about inserts, torque cones, adapters, etc it seems like sticking with 1.5" will be my best bet all around. I was considering picking up a set of these headers.
* For mufflers I've heard a lot about the Heiden-designed Commando re-issues he has. I know @5twins has talked highly about this designs.
It seems like THIS 26" Commando is that muffler, and would fit the 1.5" pipes. That sound right? (My bike is stored, but does anyone know the length of the stock mufflers, btw?)

But he also has THIS 18" XS Performance Reverse Cone which reads more like it, from the description? (Dyno-tuned baffle, etc).

I sent him a note but didn't hear back. In any case, curious to hear general thoughts on the plan, and if anyone can shed some light on the mufflers. I also realize that there may be some carb jetting mods in my future (and would gladly take any advice on that as well, although I know there is a lot out there to find).
Thanks everyone.

 

[5twins]

You want the 26" Commando, not the 18" reverse cone. The 18" would be very, very loud. My buddy had a set and sold them because of that. After hearing mine, he now runs the Commandos too. We both have the old original style ones, the good ones. 650Trader says his are that old design but I've yet to see any reports on them from a customer. I hope they are because I'd like to order some.

 

[Team Junk]

Something else to consider about the pipe length is the influence on the power curve.

Generally the longer pipes will provide a bigger and flatter torque curve while the shorter pipe will increase the horsepower peak at the expense of low rpm grunt.

This is of course a generalization with other factors coming into play. Exhaust systems have a resonant frequency like a organ pipe and need to be matched to the torque peak rpm for best torque and efficiency. Shorter pipes tend to match the peak horsepower rpm.

Bottom line is if you spend most of your time WFO the shortys are your goto. If you spend your time cruising down the highway then the commandos are a better choice.
Just my experience.
Now do you want to talk about oil?

 

[650trader]

Do not confuse 18" megaphones sold by yamahaxs650.com with those sold by Mikes/Emgo
You can see the tunable baffle design # 07-0115 baffle that is used in the 18" megaphone and
these are not loud like the perforated baffle type sold by Emgo/Mikes/others. yamahaxs650.com
is selling only the Heiden/Mike Lalonde type exhaust as they provide good power without the outrageous
noise.

 

[Capnkente]

Do not confuse 18" megaphones sold by yamahaxs650.com with those sold by Mikes/Emgo
You can see the tunable baffle design # 07-0115 baffle that is used in the 18" megaphone and
these are not loud like the perforated baffle type sold by Emgo/Mikes/others. yamahaxs650.com
is selling only the Heiden/Mike Lalonde type exhaust as they provide good power without the outrageous
noise.

I just put a set of these on my F model, and I absolutely love them. Awesome rumble, but, not enough to piss off the neighbors. Lots of low end torque!

 

[Vincenthdfan]

Do not confuse 18" megaphones sold by yamahaxs650.com with those sold by Mikes/Emgo
You can see the tunable baffle design # 07-0115 baffle that is used in the 18" megaphone and
these are not loud like the perforated baffle type sold by Emgo/Mikes/others. yamahaxs650.com
is selling only the Heiden/Mike Lalonde type exhaust as they provide good power without the outrageous
noise.

Thats the part number for the 26" megaphone.

 

[Vincenthdfan]

I just put a set of these on my F model, and I absolutely love them. Awesome rumble, but, not enough to piss off the neighbors. Lots of low end torque!

Which part number did you go with?

 

[Capnkente]

Which part number did you go with?

07-0114