Exhaust question

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Oct 26, 2022 | 05:29 PM

#11

Ken45

Thread Starter

Road Master

Joined: Oct 2022

Posts: 960

Likes: 668

From: USA

Quote:

Originally Posted by commander47

Removing the cat will not cause any immediate problems. The O2 sensor will adjust and mostly keep the bike from running too lean. At idle, low RPM and accelerating, the bike will run lean. This will cause the motor itself to overheat. How much so depends on your riding style.

Also, you need to consider your warranty on an M8.

Finally, the cat is probably the single most expensive part on the bike. At last look, the contents of the cat go for: \
Platinum: $900 per ounce
Palladium: $790 per ounce
Rhodium: $850 per ounce

I was not planning on doing any thing until the warranty runs out. Just removing the cat to reduce heat but will not do it if it will damage the engine unless a tune of some sort will prevent damage. Some say that the new ECM can not be tuned and others say it can.

Oct 26, 2022 | 05:37 PM

#12

downzero

Stellar HDF Member

Joined: Mar 2008

Posts: 2,328

Likes: 2,205

I would be very interested to see people's wideband results on the claim that it will be running "lean." How lean is lean? What is the commanded AFR vs. actual?

Oct 26, 2022 | 06:03 PM

#13

commander47

Tourer

Joined: Feb 2010

Posts: 356

Likes: 345

From: Georgia

Quote:

Originally Posted by Steelie68

Forgive me but I am a little confused by your post. Bike will be getting a catless header, slipons, power vision tuner, SE Ventilator and dyno'd. Why would bike run lean if it is tuned properly? Thanks.

I understood the OP to ask about removing the cat only. I didn't see anything about the whole exhaust.

Oct 26, 2022 | 06:12 PM

#14

commander47

Tourer

Joined: Feb 2010

Posts: 356

Likes: 345

From: Georgia

Quote:

Originally Posted by downzero

I would be very interested to see people's wideband results on the claim that it will be running "lean." How lean is lean? What is the commanded AFR vs. actual?

The scoot will run lean. How much? Depends. The pipes and motor will run hotter with the cat removed on a stock system.

It would be better to scrap the whole system and retune like Steelie mentions above.

Check out post 11 on this thread. This is just one of many:
https://www.hdforums.com/forum/milwa...questions.html

Oct 26, 2022 | 06:50 PM

#15

Ken45

Thread Starter

Road Master

Joined: Oct 2022

Posts: 960

Likes: 668

From: USA

Quote:

Originally Posted by commander47

I am going to leave the bike stock but want to cool it down, it does get hot down here in the south as you know. I have a head pipe coming that I will gut the cat from. I guess I will have to find some kind of mild tune to go with it. I will buy one of those hand held temp guns and will do a before and after readings to see how this stuff works all through the process. I think that this 2021 Road King will be powerfull enough for this old doomsday speed demon the way it is. I am probably lucky I am still alive and plan on staying that way. lol