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Discussion Starter #1
First off I know I’ll lose some performance but, I want to give this a try. If I were to go back to the OEM exhaust removing the Two Brothers Tarmac would it work ? Could I unplug the O2 sensor from the auto tune module, turn off the auto tune and run the bike on the current map the PCV has in it ? It would have no O2 sensor connected to the PCV / ECU at all. The bike would just be fueled by a map the auto tune had generated with the Two Brothers installed. Would this even work ? I ask because I’m just sick of the D*** noisy exhaust.
 

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cant you get a db killer for it? or a can with one to retrofit? the stock pipe is a drinking straw and it will need to retune a LOT to work right. my .02
 

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Discussion Starter #5
Did you gut the OEM can ?
 

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i was curious, does the grom version have this feature "
  • Sound reducing "T-Tip" standard on Tarmac mufflers (removable)."
it lists it. I'm assuming you have it in?
 

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First off I know I’ll lose some performance but, I want to give this a try. If I were to go back to the OEM exhaust removing the Two Brothers Tarmac would it work ? Could I unplug the O2 sensor from the auto tune module, turn off the auto tune and run the bike on the current map the PCV has in it ? It would have no O2 sensor connected to the PCV / ECU at all. The bike would just be fueled by a map the auto tune had generated with the Two Brothers installed. Would this even work ? I ask because I’m just sick of the D*** noisy exhaust.
If you want to go back, I highly recommend this free stock exhaust mod. :)

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This is how it sounds...


The sound is just deeper and a tad bit louder than with the muffler. I'm not sure how much performance I gave up as the engine runs really good this way. The exhaust is also about one third lighter without that big heavy ugly muffler. It's all tucked away under the bike and nothing sticks out.
 

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Discussion Starter #9
i was curious, does the grom version have this feature "
  • Sound reducing "T-Tip" standard on Tarmac mufflers (removable)."
it lists it. I'm assuming you have it in?

Not for the Grom
 

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Discussion Starter #10
naw. OEM can flows plenty for my 164... but the stock header even holds back the stock 125!

When you get time would you mind posting a couple of pics of your exhaust ?
 

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Im surprised one isnt available. Have you reached out to them? especially with that bracket failure, maybe they will just comp you one.
 

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Your PCV map would only be good for the open loop if you disconnect the wideband. No wideband and the stock ECU would be shooting for a 14.7 AFR in the closed loop. Get a new bung welded to the stock exhaust and let wideband continue to control your closed loop.
 

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Oh wait you have a flashed ECU don't you, scratch my last post then...cause I don't know, lol.
 

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If you want to go back, I highly recommend this free stock exhaust mod. :)

View attachment 79198

View attachment 79200

View attachment 79202

This is how it sounds...


The sound is just deeper and a tad bit louder than with the muffler. I'm not sure how much performance I gave up as the engine runs really good this way. The exhaust is also about one third lighter without that big heavy ugly muffler. It's all tucked away under the bike and nothing sticks out.
I like this idea sound soft and not loud like my 2014 groms finbro full exhaust. The box under the grom is just the CAT system. If I do get a newer grom I will remember this video. Thanks for posting the sound video
 

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You could just get a metal strap to replace the broken mount.
 

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I like this idea sound soft and not loud like my 2014 groms finbro full exhaust. The box under the grom is just the CAT system. If I do get a newer grom I will remember this video. Thanks for posting the sound video
Yes, just the cat. It's amazing just how quiet it is. I don't know why Honda even put a muffler on it. (lol) I bet a new cat will fit on an old Grom, and I'll bet a lot of SF guys even throw their stock exhaust away! I'm making a proper tail pipe for it right now and am going to do some longer term testing just to see how the gas mileage compares to the TOCE. With the warmer weather the gas mileage has been getting really good, with a record high of 146 mpg and an average of 138 mpg.
 

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Yes, just the cat. It's amazing just how quiet it is. I don't know why Honda even put a muffler on it. (lol) I bet a new cat will fit on an old Grom, and I'll bet a lot of SF guys even throw their stock exhaust away! I'm making a proper tail pipe for it right now and am going to do some longer term testing just to see how the gas mileage compares to the TOCE. With the warmer weather the gas mileage has been getting really good, with a record high of 146 mpg and an average of 138 mpg.
What I like to see on that setup is to remove the pipe from the exhaust port to the CAT and install a larger I/D pipe sort of what Finbro has for their set up just to help increase the flow of the exhaust to the CAT, or DIY a larger pipe and add a bung for future use.
 

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Discussion Starter #20
I have an SF
 
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