Performance issues with Mikes XS EMGO "Commando" mufflers?

[Tnrfd]

Anyone else experienced performance issues with Mikes XS Command exhaust mufflers / EMGO part-number 80-84034? Seems like the flow is really poor. Non removable baffles so not much to do without cutting them up.

I have performance problems as described in this post and things points to exhaust flow problems:
http://www.xs650.com/threads/exhaust-reversion-problem-with-mikesxs-commando-exhaust-system.54313

 

[fredintoon]

Anyone else experienced performance issues with Mikes XS Command exhaust mufflers / EMGO part-number 80-84034? Seems like the flow is really poor. Non removable baffles so not much to do without cutting them up.
I have performance problems as described in this post and things points to exhaust flow problems:
http://www.xs650.com/threads/exhaust-reversion-problem-with-mikesxs-commando-exhaust-system.54313

Hi Tnrfd,
the good ol' pointy bar trick* worked to open up the over-restrictive stock mufflers on my
'84 Heritage Special and my son's 's '80 Special.
The sound went from pf-pf-pf to Throb-throb-throb and the bike seemed to be more responsive.
* use a ~1/2 meter length of ~20mm diameter steel bar stock with a tapered chisel point ground on it's end.
Hold the blunt end with a vise-grip, shove the pointy end into the muffler until it hits the baffle then pound on
the end with a ~ 1 KG club hammer. Turn the bar through ~90º every hit so it don't get stuck and keep at it
until the baffle opens up. And like I told my son after I'd done mine and revved it up,
"You sure you want yours done because there's no backsies from this procedure."
"Oh yes!" he said.

 

[650trader]

Note: You owners with short memories: The Original Mikes XS mufflers 07-0065/0015 were Dyno developed for Mike Lalonde on
Heiden Tunings Dyno and flow bench. The real mufflers have a special baffle with a removable center plug and the mounting point is re-enforced
and has an EURO OEM ref.# stamped in the mount bracket . Emgo mufflers may look the same externally but use a baffle meant for a small bike.
No engineering there just a lower price.

 

[willis]

That may be true, but Mike's still advertises them as the old mufflers. I wrote up a thread addressing this as a buyer beware, as Mike's is pulling a bait and switch product.

"Commando Style dyno tuned* Megaphone Muffler.An "XS Performance" part. Dyno tuned design by Heiden Tuning for improved power at all RPM's and good sound.Chrome Megaphone is 26" Long x 3 7/8" end Dia. with a welded in mechanical steel baffle, welded on end cone and a reinforced mounting bracket positioned to improve fit to the XS chassis. Fits to 1.5" inlet (38.5mm) with reducing sleeves. OD headpipes and includes a hanger strap and clamp. Steel non-removable baffle."

http://www.xs650.com/threads/commando-opinions.52753/

 

[650trader]

Still it's easy to check if they are as advertised. They will switch if the part is a sheckel less.

 

[TwoManyXS1Bs]

An affluent enthusiast could buy one of those EMGO mufflers, saw it lengthwise down the middle, and post pics. Then, folks might be able to cook-up gutting mods...

 

[Tnrfd]

I have now drilled several holes through both baffle plates in the muffler and only a slight improvement. Now I can see through the mufflers. It's still like the engine hits a rev limiter at 4000rpm and starts stuttering.

I've tried with some other open (and stupid loud) mufflers and then the engine works perfectly so def. a problem with the mufflers. I'm baffled....

 

[arcticXS]

Go in from the front with the largest hole saw that fits, on a suitably long extension?
That may help, or not.
I actually bought some aftermarket Norton Commando peashooter style mufflers to fit my 1 1/2" single wall headpipes. They fit well, and looked beautiful. But sounded horrible on my XS,
These Norton peashooter mufflers have a louvred core with no packing between core and muffler body. And sound almost like a 2 stroke when fitted to an XS. Must have something to do with valve sizes and cam profiles vs. a Commando 750 or 850, as those always sound real nice.
In any case, I do believe a perforated, straight through core with 35 mm ID and of sufficient length, packed with fiberglass, is the best solution for power and sound. Both my Ducatis have slip ons with this type of muffler core, and they sound really good, and perform well.

 

[Techman]

Sometimes a challenge attempting to get that slip on 1.5" to 1.75" header to muffler fit. Some of the aftermarket mufflers do include reducers and such. This is may be some assist to seal those situations. This is a muffler joint gasket you can get from MikesXS p/n 07-4622

 

[Mailman]

Like Fred said earlier, the easiest fix, really is the easiest. I went to Home Depot and bought a 3’ long 1/2” diameter piece of re bar. Ground a chisel point on one end and start beating from both ends until you can see through. It usually doesn’t even require a sight line straight through to get a deeper sound. Often it’s just a matter of removing one or two obstacles and the sound will get much deeper.

I did this in a late model Triumph.