Stock Muffler/Boat Anchor

[A1VW2NV]

While I'm waiting for my new exhaust to be made, I thought I'd cut open my stock muffler and see if I could modify it for better flow and sound. First thing I noticed after wrestling it off? IT WEIGHS A TON!! I haven't actually weighed it, but I'd guess its 12-15llbs!
I then cut the outer shell in half. The outlet pipe needed to be relieved from this outer shell/case so I drilled several holes around it. This allowed me to separate the halves. At this point I got a better idea of what was going on inside. There is a perforated core/baffle that is surrounded by the glass packing material.The packing goes between the core/baffle and the outer shell. The next part to get the cut off wheel was the perforated core. This proved to be harder than anticipated. There are several spot welds that hold the inner piping and brackets. These needed to be drilled out. With some help from a buddy, we finally were able to separate the inner core's. SUccess! We can finally see what is going on in there. The is a lot of internal tubing and a small cat. After seeing this I've come to the conclusion that this muffler is very restrictive and produces a lot of back pressure. I haven't decided if I will modify this or wait for my new exhaust yet. I guess we'll see in a couple of days.

 

[Fasteddy]

Thanks for posting the pics, that gives some idea of whats going on in there.

 

[guzz46]

I weighed mine, it came in at 5.2kg.

 

[mr-fabricator]

Yep did the same to mine , cat was removed and put it all back together .

Note change for the better and via bum dyno breathes a little better to .

Good work

Regatds lee

 

[A1VW2NV]

Yep did the same to mine , cat was removed and put it all back together .

Note change for the better and via bum dyno breathes a little better to .

Good work

Regatds lee

Lee, did you reuse the packing between the core and the outer shell?

 

[b0Xcrash]

While I'm waiting for my new exhaust to be made, I thought I'd cut open my stock muffler and see if I could modify it for better flow and sound. First thing I noticed after wrestling it off? IT WEIGHS A TON!!

Nice! I was curious about this myself, and with a close family member with amazing welding skills thought about this myself. Done it before on dirtbikes back in the day and it worked wonders until I could cough up cash for a good can.

I almost wonder if you could take a stubby can or a d&d can, cut down and fit it in that area, then using the stock section of pipe coming off header and the stock section for the tip that comes out of the belly pan mount it up with some alum brackets or something.....

 

[Formula390]

I almost wonder if you could take a stubby can or a d&d can, cut down and fit it in that area, then using the stock section of pipe coming off header and the stock section for the tip that comes out of the belly pan mount it up with some alum brackets or something.....

You could, but performance would suffer. Any modifications to the intake or exhaust will also require remapping the ECU with the Akrapovic map at a minimum, and almost certainly will also require a Power Commander tuned to the exhaust. I'm getting VERY close to being production ready for my exhaust system (see thread http://www.rc390-forum.com/forum/engine-and-technical-discussion/395-exhaust-development.html) which will retain the stock exit location. I will require the Akrapovic map on your ECU and a Power Commander, just like all the other aftermarket exhausts. There is also the GPR Power cone, which retains the stock location, but has a "pea shooter" exhaust exit out the bottom of the belly pan which... let's just say... hasn't been well received. LOL The GPR system has the advantage that it's available today, where as I'm probably still a week and a half to two weeks out from going into production...

 

[b0Xcrash]

You could, but performance would suffer. Any modifications to the intake or exhaust will also require remapping the ECU with the Akrapovic map at a minimum, and almost certainly will also require a Power Commander tuned to the exhaust. I'm getting VERY close to being production ready for my exhaust system (see thread http://www.rc390-forum.com/forum/engine-and-technical-discussion/395-exhaust-development.html) which will retain the stock exit location. I will require the Akrapovic map on your ECU and a Power Commander, just like all the other aftermarket exhausts. There is also the GPR Power cone, which retains the stock location, but has a "pea shooter" exhaust exit out the bottom of the belly pan which... let's just say... hasn't been well received. LOL The GPR system has the advantage that it's available today, where as I'm probably still a week and a half to two weeks out from going into production...

Right, sorry about that, I was going with the "assumed" most knew that you could not run stock ecm/pcb.......I left that part out. I was going on the fact that you would need a PCV and or even a different air cleaner as well.
Considering there seems to be only the one Akrapovič map out there now, and of course in time, there will be plenty more, an aftermarket filter, modified stock can map might make dev.

Or, you can do what I have done in the past with the PCIII USB and tune each interval of a base map with a dyno or even more painful butt dyno so that when you do go to the actual dyno you are pretty darn close and might need a tweak here or there(yeah showing age, had some of the old serial port PC II models as well)

Which with that being said...really like to see Bazzaz come out with one, considering the tuning that could always be done with theirs, but than again noticed they don't even have one for the 390 Duke.

Going way off topic, but that was one thing I liked about the R6: 03, 04, 05 that I had experience with, was you could run A/F from the gauge clustering, unlocking the feature, and accessing the ecm like factory...it took a little more adjusting and messing with, but thanks to outlets like this you could share what WERA or other race teams used(I even remember Graves sharing info) to get the best setup with slip-on, filter and header x,y,z.

 

[b0Xcrash]

You could, but performance would suffer. Any modifications to the intake or exhaust will also require remapping the ECU with the Akrapovic map at a minimum, and almost certainly will also require a Power Commander tuned to the exhaust. I'm getting VERY close to being production ready for my exhaust system (see thread http://www.rc390-forum.com/forum/engine-and-technical-discussion/395-exhaust-development.html) which will retain the stock exit location. I will require the Akrapovic map on your ECU and a Power Commander, just like all the other aftermarket exhausts. There is also the GPR Power cone, which retains the stock location, but has a "pea shooter" exhaust exit out the bottom of the belly pan which... let's just say... hasn't been well received. LOL The GPR system has the advantage that it's available today, where as I'm probably still a week and a half to two weeks out from going into production...

Right, sorry about that I left that out, but I totally understood that.
I guess I assumed everyone else was aware you would need a PCV or some engine management adjustments made, and even possibly a upgraded air cleaner to balance it out.

Of course it appears at this time the PCV only has the Ark map. I know it won't be long before a number of other maps come into development as time goes on.
Of course you could always use a base map and fine tune each interval. I have done this before myself in the PCIII USB days(I admit I have been around since the PCII, serial, days using those) and from dyno results of others with a very similar setup, and the butt dyno first, it can save some time at the real dyno with little tweaks here and there or virtually none at all, nice smooth linear curve.

Be real interesting if Bazzaz comes out with AF mgmt for the KTM, but than again they do not even have one out for the 390 Duke.

 

[b0Xcrash]

You could, but performance would suffer. Any modifications to the intake or exhaust will also require remapping the ECU with the Akrapovic map at a minimum, and almost certainly will also require a Power Commander tuned to the exhaust. I'm getting VERY close to being production ready for my exhaust system (see thread http://www.rc390-forum.com/forum/engine-and-technical-discussion/395-exhaust-development.html) which will retain the stock exit location. I will require the Akrapovic map on your ECU and a Power Commander, just like all the other aftermarket exhausts. There is also the GPR Power cone, which retains the stock location, but has a "pea shooter" exhaust exit out the bottom of the belly pan which... let's just say... hasn't been well received. LOL The GPR system has the advantage that it's available today, where as I'm probably still a week and a half to two weeks out from going into production...

Right, yeah sorry, I left that part out, I knew that much, and I guess I assumed everyone else would as well.
I have been messing with the PC's since the PCII serial port days

It obviously would require a PCV and possibly even an upgraded air filter. Depending on ECU and manufacture, you can do it without and EFI makes very small adjustments, but you loose all street ridability or power usability, as well as fuel efficeny, occasional back-fire and sputters....which is performance suffering
I did like the fact on the 03, 04 and even 05 R6 you could adjust A/F from cluster after unlocking the feature, asked Yamaha Factory race team about it, well Graves to be more specific.
Seems at this time only a Akrapovič map exists, which I know in time there will be plenty available once developed.
Which this base map would work and then you can tune each interval and make adjustments with a dyno.

Which a Bazzaz would make things interesting if they ever release one for the RC, but looking it seems they do not even make one for the Duke 390.

 

[b0Xcrash]

Right, yeah sorry, I left that part out, I knew that much, and I guess I assumed everyone else would as

well.
I have been messing with the PC's since the PCII serial port days

It obviously would require a PCV and possibly even an upgraded air filter. Depending on ECU and

manufacture, you can do it without and EFI makes very small adjustments, but you loose all street

ridability or power usability, as well as fuel efficeny, occasional back-fire and sputters....which is

performance suffering
I did like the fact on the 03, 04 and even 05 R6 you could adjust A/F from cluster after unlocking the

feature, asked Yamaha Factory race team about it, well Graves to be more specific.
Seems at this time only a Akrapovič map exists, which I know in time there will be plenty available once

developed.Which this base map would work and then you can tune each interval and make adjustments with a

dyno.
Which a Bazzaz would make things interesting if they ever release one for the RC, but looking it seems

they do not even make one for the Duke 390.

 

[CDN Duke]

We can finally see what is going on in there. View attachment 493View attachment 494 The is a lot of internal tubing and a small cat.

Great pics A1VW2NV

I'm interested in more tone from the exhaust currently - recognizing that this stock configuration is actually quite good for power, there's a reason it's constructed/routed the way it is inside. Can you clarify how the exhaust is getting to the lower chamber? Is it just coming down the tailpipe from above? The reason I ask, is I've seen this video https://www.youtube.com/watch?v=TAk1ABgcO04 where dude put a large hole adjacent the tailpipe exit and it made a huge difference in sound, just wondering how the exhaust routing is modified.

 

[btalont]

Yes, I added a Bazzaz when I changed out the exhaust. With the self mapping feature, made a big difference in power, especially mid-range. I was able to pull up and pass a stock bike on the front straight at TWS from 20 bike lengths back!

 

[Andy]

Just ditched my stock silencer, can't believe how differentl/better the bike now handles even on stock suspension!



Only issues now are the fruity tone and getting some sort of remap!

 

[chrisdigital21]

Just ditched my stock silencer, can't believe how differentl/better the bike now handles even on stock suspension!

View attachment 3068

Only issues now are the fruity tone and getting some sort of remap!

FRUITY, LMFAO

I am putting my stock system back in its home and selling my GPR GHOST.