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Discussion Starter · #1 ·
So I've got the Akra header with Ivan's re flash package. I bought tnfrosty's M4 slip-ons he was selling. They came today and I mounted them up in the shop and, yep...it's LOUD. They sound really good at idle and a low rev but got a lot of bark at higher revs. I haven't ridden with them yet though, so they may be ok on the road.

I see M4 has two versions of inserts, level 1 and 2 or something like that, but both are listed as not comparable with the Z1000 / Ninja M4's. I'm gonna call and ask why, but does anyone know why, or have tried them to see if they can be made to work? They're only $35 so it'd be cheap to try unless they are wrong diameter and just won't go down inside the slip-ons.

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Discussion Starter · #2 ·
So been doing some Google-foo and seen a thread on Z1000 forum where a guy had M4's and then did Ivan's reflash kit with Akra headers and stated...

The M4 exhaust was fine with stock heads but was way too loud (to the point of hurting my head!) after installation of the kit above. A phone call to M4 and they shipped me out a set of Level 2 silencers. About a 10 minute install later, my exhaust is back to reasonable decibels.

Maybe this will work...

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Discussion Starter · #3 · (Edited)
So, spoke to M4 this morning. They DO have inserts available for these cans. Your can needs to be the newer style that has a groove around the ID for a C-clip to hold the insert in.

The Stage 1 insert, he said would "take the edge off" and drop about 1-2 db.

The Stage 2 insert, he said would drop about 3-4 db and maybe feel it in performance. It reduces the ID of the can about in 1/2.

He didn't have any pics of the inserts, but I've been able to find some on the web. The Stage 2 certainly looks a LOT more restrictive. I ordered the Stage 2 inserts from him right over the phone. They are $35ea and come with the needed C-clip (other sites charge up to $11 for the clip extra).

My plan is to start with the Stage 2 inserts, see how they sound and feel. If needed, I'll open up the hole in the disk that is on the bottom of the insert (would be deep in the muffler) a little at a time until I get to the tone I like. If that's not enough, I'll drill some holes around the flange on the exit end of the insert.

Below are pics I found online.

Stage 1 vs Stage 2 inserts


Stage 2 insert installed - to show how much it reduces the ID


Following are just more pics of the Stage 2 from different views.








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Discussion Starter · #5 ·
Ain't rode it yet, RC. Just got the M4's Sat and put them on. Just ordered the inserts this morning.

I did ease about 1/4 down the road yesterday in no gear, so really didn't get on it at all, just to see what they sounded like to the naked ear.
Again, they sound good, but are LOUD - like standing beside the speaker at a rock concert L.O.U.D. :headbang:
They do sound good - but it's just WAY TOO much of it.
Probably very little difference in running an open header.

When talking the guy at M4 and told him I had them behind an Akra header his response was "OH YEAH......they are going to be *really* loud if they aren't behind a bread box" :silly:

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Discussion Starter · #6 ·
So just to update...inserts came today. They are a little different on the exposed end than what's in the pics above, newer design maybe? Anyway, they toned the volume down quiet a bit but are not stock muffler quiet by any means (I wasn't shooting for that anyway). They sound really good and I plan to ride it a while before deciding to open the hole on the disk up or not.

One thing I didn't like was each insert included the C-clip but one was silver and one was black???? I'll paint the silver one with hi temp grill paint so they match, I guess.

Good to know and confirm that anyone who likes the M4 slip-ons and run a header have a useable option now that isn't NHRA dragster loud.

I'll post some pics tomorrow when I can and give a ride report when it stops raining.

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what i would do is remove that plate with tiny hole, get some fiberglass wrap, and wrap the stem of the baffle, dont tighten the wrap or it will be loud again, insert and done..
those exhaust like brawlers and m4 are loud because they are close to the rider, thats why aftermarket header for upright positioned bikes are longer we are not like supersports that are leant forward, exhaust sound resonates like 3x
inside the helmet.. so better wear earplugs, i do in my 2 exhaust set-ups and made it a habit.. saves your hearing in the long run including helmet noise and such
anyway have somebody ride the bike and do a ride by.. see and hear how loud it is
cheers
 

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Discussion Starter · #8 ·
I got out for a little ride yesterday. The inserts sounded good but I decided they weren't much louder at idle and low revs than the stock mufflers were with the Akra header. When I got home I pulled the inserts and drilled the 1//4" hole in the end plate out to 5/8". It raised the volume a little and I'll wait til I ride it before doing anything else to them.

Overall, I am really pleased with these slip-ons. I wanted duals that worked with the factory saddlebags, sounded good, were Carbon or black and weren't $800+. So far, these fit the bill.

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