XS 'Commando' bolt on performance?

[Chicken_Feet]

Hi there team,

I have a stock 78 xs650 standard which I have just purchased. It runs beautifully but was looking for a different sound as well as the chrome flaking off the exhaust in some areas.

If the Commando Style Megaphone Mufflers from XS performance were bolted onto the stock headers and with no changes to needles/jets, would they hinder or improve performance on the stock XS?

They sound and look great but I don't want to lose any of my HP.


Thanks in advance!
Mat

 

[figure8]

I can't say either way, but you're not gonna lose HP. Just may need to up jets to compensate.

 

[gggGary]

If you aren't willing to change the jets, don't touch the mufflers. Sadly many bikes with holed pistons have passed through my shop, because the PO didn't think he needed to change jetting "just for a muffler".

These give a bit more throat without being obnoxious.

"Dunstall" style replica Universal 27 3/4" motorcycle muffler reverse cone
"Dunstall" style replica Universal 27 3/4" motorcycle muffler reverse cone Photo "Dunstall" style replica Universal muffler with reverse cone.
Non removable metal baffle
Includes inlet clamp, sliding bracket, 1 5/8" 1 id and 1/2" id, 1 3/8" id with adapters. 27 3/4" long. Sold EACH.
Part #07-0774 $75.50 USD Ea.
There are threads about jetting but expect 1 or two sizes up on the mains and mid jets.
If you are past the look at me stage in life don't pick any of the other, removable or fiberglass baffle types, you won't be happy.

 

[Chicken_Feet]

Ok, cool. Thanks for the info.

I wasn't looking for an increase in DB, I just wanted a deeper, less tinny sound.

I know they sound great but do the Commando's or Dunstall's have a big increase in DB as well?

 

[5twins]

I think the Commandos are near perfect, slightly louder than stock but not overly loud. They make the bike sound like a motorcycle should, in my opinion. I don't recommend those Dunstall reps Gary mentioned AT ALL. That is what I started out with. I thought they were OK until I got the Commandos, then I saw just how bad they were. I mounted one Commando next to one of the Dunstalls and started the bike. Boy, did that drive the point home as to what a shit muffler the Dunstall was. Also, besides the crappy sound, one of the "fixed" baffles broke loose and fell out after a few hundred miles.

If you learn a bit about the 650 carb history, you'll discover that your '78 carb set came with the biggest mains ever put in a 650, #135s. If the mufflers are your only change, you shouldn't need much, if any, rejetting. You could and should try one size larger mains, just to be sure, but that would probably be all you'd need (if you even needed that).

 

[Chicken_Feet]

Great, thanks for the info, team!

Much appreciated

 

[5twins]

If you get the Commandos, get the 1.5" inlet ones, not the "universal fit" ones that come with adapters for multiple different sized headpipes. They never seal right.

 

[Chicken_Feet]

Haha was just looking at that

Will do, thanks mate!

 

[gggGary]

My mistake, yes the commandos not the dunstalls are what I run. they now include the metal strap that makes them easy to mount to the stock footpeg/muffler bolts. Don't go near Emgo (look like commando) mufflers, either sound is awful and they are TOO restrictive. An old guy (like me) ordered the short mufflers instead of the 26"s then asked which he should buy. He is now all "DO NOT say I told you so! Know anyone wants a pair of 17" mufflers?"

 

[XSLeo]

If you do get a universal set of mufflers that are 1 3/4 inlets with reducers to fit smaller pipes, throw away the clamps that come with the mufflers. They are not strong enough to get a good seal.
Go to the nearest Harley dealer and get their 1 3/4 clamps. They are very strong and will seal. Last time I checked they were $7.99 each.
I'll post a pic. You can see how heavy the strap is and the bolt is 3/8 inch. You can really torque them down.
Leo

 

[Chicken_Feet]

so i got the 1.5" commandos and they are too small to get over the headers. Must be after market headers. Im guessing the headers are 1.5" also as they look the same diameter. Anyone have any suggestion? Send back (headache) or is there a fix i can do to get them on?

 

[5twins]

If it's very close, you can probably use a tailpipe expander tool to "stretch" the muffler opening a little .....

http://www.harborfreight.com/automotive-motorcycle/exhaust/small-tail-pipe-expander-69550.html

 

[Chicken_Feet]

how far can you stretch the pipe? Will it not effect the chrome?

 

[Chicken_Feet]

I have just decided to return them for the universal ones! Are xs650direct good with returns?

 

[Jaymerica]

Hey Chickenfeet,
How did you make out? I've got an '82 Special II that I'm looking to up the beefiness of the sounds with. I'm not necessarily looking to replace the whole exhaust, rather just the muffler as well. I had my eyes on the Commando. Any chance for a video or a soundclip for reference?
How was the install? Did you change the carbs at all?

 

[Chicken_Feet]

Not sure yet mate. I just returned the original 1.5" set and waiting on the universals. On holiday atm but will put them on in 6 weeks. I'll follow up once they are on. Just make sure what your header pipe size is haha I did not.... Hence the delay

 

[Chicken_Feet]

Bit from my research and the advice from the experts here, they sound like the best choice!