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Discussion Starter #1
Remove the cat today, exhaust sounds a little deeper after the removal.
Used a big screwdriver and hammer to remove.
 

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Discussion Starter #5
After the exhaust pipe was removed it took about 10 minutes to get the converter out. Can't ride yet, started snowing this afternoon.


bluesurf said:
nice. how long did it take?

and more importantly, how was the post-removal test ride?
 

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I'm going to have my bike dynoed next week. I'm planning on removing my cat also. I''ll have it dynoed again after to see the actual gain if there is any. I'm wondering how long the job took also?:dunno
 

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I hope you have done a dyno before and after and are able to show us that you did gain nothing....
 

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Juerg said:
I hope you have done a dyno before and after and are able to show us that you did gain nothing....
Uuuh.... and you are saying what?:dunno
 

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You need to change the mapping after removing the cat. Otherwise the engine will run lean. Not really good for it, especially during break-in.
 

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Stock jetting is usually a little rich on the top end and a little lean in the low/mids. Gutting the cat shouldn't screw up the mapping as far as top end hp. He should actually see a small gain in top end hp. It's kind of like installing a better flowing can on any other bike. You will get a small gain and you don't have to remap with a PC3 but you might get a little more gain with a very mild midrange remap. There is no chance of hurting anything by gutting the cat.

I am curious to hear if the midrange and light/cruise throttle feels lean at all....... any light surging? I doubt just gutting the cat would cause this but gutting the cat AND install aftermarket cans together might lean out the mids enough to feel it.

Thanks for the pics, those are great! Without having to search through additional posts, can you tell us if you're still running the stock cans?

In looking at your pics, it appears that the cat was only about 1 1/2" thick. Is that correct?
 

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Juerg said:
I hope you have done a dyno before and after and are able to show us that you did gain nothing....
Why would you think that removing a brick in the middle of your exhaust system would not result in any hp gains? Gutting the cat should produce similar gains to installing a more free flowing can. Yamaha themselves already admitted the cat killed off 2hp.

Maybe over in Switzerland you guys don't have a lot of experience with catalytic converters. Over here in the USA, we've had them since approx. 1975. I've personally removed/gutted at least 50 cats on carbueted and fuel injected cars over the years. Each and every single one gained hp and went faster in the 1/4 mile in both E.T. and mph.

As far as exhaust flow in concerned, gutting the cat is no different than installing a more free flowing can. Same results, same jetting requirement, will not hurt your bike.
 

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Amen!
It will lean it out just a little.
Now, if you were to do that mod with new exhaust cans and a free flowing air filter you would be running way lean.
 

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Seems like this mod will help many people out as they don't care to change out their OEM systems therefore cutting down on cost as well. Perhaps using the YEC slip-ons along with this mod may be the ticket for someone.:sneaky

BD
 

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Discussion Starter #17
I installed a PCIII usb on the bike at the same time so I'm not too concerned with the lean condition. The cat is about 2-2.5" inches long in the pipe.
 
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