What difference would removing the T120 cat make?

I have a T120 Bud Ekins edition, and although I like hanging farkle as much as the next guy, I don’t want to upset the aesthetics of this particular bike.
On the other hand, I wouldn’t mind saving weight and adding power. I haven’t seen any aftermarket exhausts that don’t change the way the bike looks, and I like the pea shooters. What if I simply removed the cat and replaced it with empty pipes?
Would it make any difference? Rumor has it it’s a big (-ish) job.

I haven’t done it myself, so can’t really advise, but I’ve read plenty of comments on other forums, as it’s quite a popular mod. All say that it makes the bike louder. Some say it increases the performance a bit, others say it doesn’t and just results in more noise. I’m personally very happy with the sound my standard Street Twin makes, and wouldn’t want it any louder. In my experience, an over-loud exhaust gets very tiring when riding any serious distance.

Thanks for your comment, Dave. I agree with you: the sound of the stock bike is so nice that I’d hate to change it for no good reason.

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add to that it might be necessary to load a new prog to the ECU to have a smooth working bike.

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I seem to remember that @Andyc1 de-catted his Bonneville quite soon after he got it - should be in a thread on here somewhere.

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I found it, thanks. He said the sound stayed okay but didn’t mention any change in performance. I wonder if it saved much weight.

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The newer Bonnies have 3 cats now, one under the engine and one in each silencer. Just removing the one under the engine didn’t make much difference. You would need to remove all 3 to notice much difference. They are making it harder hand harder to remove them too. When I took the cat off my 1200 thruxton it resulted in a superb noise (not loud) and performance felt better.


Thanks for the info, Andy. There’s a company called Motone, or something like that, which makes cat-delete pipes; did you use them?
What I’d really like to do is get the bike to have more-instant throttle response like my Suzuki, which acts like it has carbs. Some Triumphs (and other brands) seem to want to think about it for a beat before increasing fuel flow.
I’m just wondering if freeing up the exhaust might give better throttle response.

Does your Bonneville have a Sport mode? If so that will sharpen the throttle response?

No, it only has ROAD and RAIN modes.

I think it was Black Widow I used for the cat under the engine. When I done my 2016 Thruxton, the cat was easily removed but you still have to partially remove a piece of the chassis frame to get it out. There were no cats in the silencers either. The newer Bonnie had the cat under the engine welded to the rest of the exhaust and 2 additional cats. I don’t know what year they made these changes. If you can get rid of all the cats then it’s worth it IMO. there is also a snorkel on the air intake, that’s very easy to remove. Do all that and you should feel a little difference.