Leo Vince muffler.

I recently fitted one of these to my '07 Swing and was very impressed by the quality of the product including the mounting hardware, Top gear . It took me about 45mins. to complete a very easy installation. The new unit is wee bit louder at standstill and around the traps but seems the same at highway speeds .It does however provide a nice deeper rumble to the exhaust note.What was a bit disconcerting on that first run was the a-poppin'n'a-bangin' that occurs on the overrun e.g. slowing and stopping at traffic lights. Is this normal or does something need tweaking somewhere ? I am also left with a thin round SS disc of 50mm diameter which has five 9mm holes punched in it with the no.50 stamped on one side. This was not identified by either the written or pictorial instructions but it is fairly obvious that it is a baffle for somewhere in the muffler outlet. Could its omission be the cause of the noise described and - where is it meant to fit???

G'day mate, our Canadian friend bigbird is the bloke with the answers to your queries, he fitted a Leo Vince to his Silver Wing a few years ago.

I too have the disc (somewhere!) as I could find no mention of it in the instructions.  The popping on the overrun tends to go once the system is really hot.  I suspect that the cone joint gets tighter as things heat up and expand.

I just read the thread title and you piqued my interest in this one.
My LeoVince 8552 muffler was apparently the first imported into N. America 3 years ago for me by the US distributor. Perhaps it has since been redesigned, as I had no disc supplied as you describe. I do have a rather large drilled tube that is called the dB Killer, and is just a fancy name for the baffle that makes the muffler acceptably loud for street use. This tube slides into the end of the muffler and tightens with an hex screw. Removing the dB Killer made the exhaust ridiculously loud and annoying, especially at steady highway rpm. The droning drove me crazy. After that highway ride, I put the dB Killer back in and haven't removed it since.
The popping and crackling on throttle back off is normal. It's caused by air injected into the exhaust system by the PAIR valve in the engine. It's purpose is to complete the combustion of unburned hydrocarbons in the exhaust, before they pass through the catalytic converter in the stock muffler. It's normal. I like it, but if you don't, you could always disable your PAIR valve. Check the service manual if that's the route you want to go. You really don't need the PAIR valve once the stock muffler is removed, because then the catalytic converter is gone as well. I have left my PAIR valve intact. Hope this helps, even though I have no idea about the drilled disc you both have.

I was one of the early ones to fit a leo vince exhaust on my bike, somewhere around 2004.
That model was the "4road" exhaust. I don't know if that is the same model you have.
Keep in mind that certain later stock exhausts also had an oxygen sensor.
Do not know if Leo Vince was modified to adapt to that.

I recommend adding to your bike a power commander.
This device, when properly mapped, will optimize your fuel/air mixture across the power band.
This should improve gas mileage, and reduce the crackling and popping from unburned fuel.

As far as the DB killer goes, I saw a very interesting modification.
A person had used extra long versions of the screws provided and placed them inside springs.

When there was little pressure, such as at idle or low speeds the springs kept the db killer in place.
As the pressure (speed) increased the db killer was pushed out of place (against the springs) allowing more air to flow.

Thus he had the best of both worlds. Quieter at idle and faster at speed.

Dan

Thanks one and all for the replies . The unit is the 8552 mentioned complete with dB killer and the adptr.to fit the O2 sensor or not with a blanking plug provided.My Swing is a late '07 made in October of that year which has a sensor and which I re-installed. As I have only ridden a short distance since the change-over I might just leave things as they are for now as I can quite easily live with the crackle. It does,as mentioned ,tend to lessen as things heat up.As for the mystery disc,for interests sake, I guess I could contact the manufacturer.

PAIR valve is the answer to your problem as bigbird describes above.Usually you struggle a hose from the air filter box which leads to the PAIR valve in order to bypass it.I'm not sure for SW though.Keep us informed .

Thanks agin guys.Would disconnecting the PAIR valve solenoid have the desired effect without upsetting any of the other electrickery ?

ericclapham wrote:

Thanks agin guys.Would disconnecting the PAIR valve solenoid have the desired effect without upsetting any of the other electrickery ?

Very cool word.  I'll have to start using it.

The PAIR valve is a mechanical device. It doesn't need any electrickery, as it is just a reed valve. The solenoid, which relies on electrickery, allows the flow of filtered air from the PAIR valve into the exhaust once the engine is warmed up ( up to model year '07) or the emissions control system is in closed loop mode ('08 and after).

17:34:53DSPEVAK .Feel free to use the word .I have picked it up somewhere on my travels. Another phrase I like when referring to things electrical is "the jelly beans."

Does anyone know what the weight difference is between the 8552 and stock that it replaces?

LDB wrote:

Does anyone know what the weight difference is between the 8552 and stock that it replaces?

The 8552 is a straight through design with no internal baffling. It also has no catalytic converter, as does the stock muffler. The 8552 weighs 9 lbs. The stock muffler weighs 18 lbs (I just weighed mine for you), for a net savings of...... 9 lbs.

Thank you for doing that. That would be a nice weight reduction.

LDB wrote:

Thank you for doing that. That would be a nice weight reduction.

You're welcome.

For another 5-6 lb weight reduction, you can replace the stock AGM Yuasa battery with a Shorai or similar Li-Fe battery.

Won't a straight-thru muffler cause the engine to run lean? If so, how could you compensate for that lean condition without reverting to a Power Commander?

Tim

That's a good plan although I'll probably run the stock battery for a year at least. When it's time for a new batter I'll definitely go that direction.

Cosmic_Jumper wrote:

Won't a straight-thru muffler cause the engine to run lean? If so, how could you compensate for that lean condition without reverting to a Power Commander?

Tim

On the '08 and later models the Lambda (O2) sensor detects too much or too little O2 in the exhaust. A rich mixture needs more O2 to burn completely, and a lean mixture will have excess O2 (needs more fuel to use the excess O2). The high voltage (rich) or low voltage (lean) from the O2 sensor goes to the ECU, which adjusts the fuel injector pulse width (how long the injector remains open), determined by many parameters.
So any fuel injected engine with a closed loop operating system (lambda sensor) can control the fuel mixture based on its own self monitoring. An open loop system, like those used on '07 and earlier Silverwing engines, would need a Power Commander or similar device to remap the pulse width adjustment. However, a Power Commander also adjusts ignition timing as well as fuel injection mapping.
So yes, Tim, an '07 or older would require a Power Commander to not run lean, an '08 or newer, no.
I have checked the plugs on my '09 a couple of times with the LeoVince straight through muffler, and their burn signature is perfect. Of course I reinstalled my O2 sensor in the LeoVince. if I didn't, I would have a bag of problems.

I would like to purchase a Leo Vince 8552.

kreiseldave, do it there's nothing stopping you. Now if you want some advice or help with something it would be best if you introduced yourself HERE Then post any questions you may have. This site is a very helpful site, but a introduction is the best first post.