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Discussion Starter #1 (Edited)
OK, I HAVE A 1999 CBR900RR. I BOUGHT A USED DEVIL SHOTGUN EXHAUST. I PUT IT ON THE BIKE ONLY TO LEARN I STARTED GETTING DETONATION UPON DECELERATION. I CHECKED THE CANS AND THEY WERE EMPTY, NO BAFFLES AT ALL. I REPACKED THE CANS AND TOOK IT FOR A RIDE AND NOW THE TORQUE IS BACK. SO FIGURING IT MIGHT NEED BETTER FILTRATION SO I PUT BACK IN THE K&N FILTER AND WENT TO START IT WITH THE CHOKE ON AND IT WOULD NOT START. SO I SHUT THE CHOKE OFF AND IT FIRED RIGHT UP. I WOULD THINK WITH THE AFTERMARKET EXHAUST AND THE K&N FILTER IT WOULD BE RUNNING LEAN. THE CARBS HAVE A FACTORY PRO STAGE 1 KIT AND I JUST ORDERED SOME 135 MAIN JETS TO DO THE VIKING MOD, BUT I AM WONERING IF IT IS ALREADY RUNNING TO RICH? PLEASE GIVE ME SOME ADVICE!
 

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OK, I HAVE A 1999 CBR900RR. I BOUGHT A USED DEVIL SHOTGUN EXHAUST. I PUT IT ON THE BIKE ONLY TO LEARN I STARTED GETTING DETONATION UPON DECELERATION. I CHECKED THE CANS AND THEY WERE EMPTY, NO BAFFLES AT ALL. I REPACKED THE CANS AND TOOK IT FOR A RIDE AND NOW THE TORQUE IS BACK. SO FIGURING IT MIGHT NEED BETTER FILTRATION SO I PUT BACK IN THE K&N FILTER AND WENT TO START IT WITH THE CHOKE ON AND IT WOULD NOT START. SO I SHUT THE CHOKE OFF AND IT FIRED RIGHT UP. I WOULD THINK WITH THE AFTERMARKET EXHAUST AND THE K&N FILTER IT WOULD BE RUNNING LEAN. THE CARBS HAVE A FACTORY PRO STAGE 1 KIT AND I JUST ORDERED SOME 135 MAIN JETS TO DO THE VIKING MOD, BUT I AM WONERING IF IT IS ALREADY RUNNING TO RICH? PLEASE GIVE ME SOME ADVICE!

By "detonation" do you mean popping in the exhaust system under closed throttle? Detonation is inside the combustion chamber and does severe damage.
What are the mixtures set at?
 

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OK, I HAVE A 1999 CBR900RR. I BOUGHT A USED DEVIL SHOTGUN EXHAUST. I PUT IT ON THE BIKE ONLY TO LEARN I STARTED GETTING DETONATION UPON DECELERATION. I CHECKED THE CANS AND THEY WERE EMPTY, NO BAFFLES AT ALL. I REPACKED THE CANS AND TOOK IT FOR A RIDE AND NOW THE TORQUE IS BACK. SO FIGURING IT MIGHT NEED BETTER FILTRATION SO I PUT BACK IN THE K&N FILTER AND WENT TO START IT WITH THE CHOKE ON AND IT WOULD NOT START. SO I SHUT THE CHOKE OFF AND IT FIRED RIGHT UP. I WOULD THINK WITH THE AFTERMARKET EXHAUST AND THE K&N FILTER IT WOULD BE RUNNING LEAN. THE CARBS HAVE A FACTORY PRO STAGE 1 KIT AND I JUST ORDERED SOME 135 MAIN JETS TO DO THE VIKING MOD, BUT I AM WONERING IF IT IS ALREADY RUNNING TO RICH? PLEASE GIVE ME SOME ADVICE!
Stop messing with it while it was working in the first place ;)
 

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Discussion Starter #4
Detonation I mean "Popping in the exhaust"! The Air mixture screws are set at 2.5 turns out as per factory pro. Last night I took it for a ride and I noticed after it warmed up, it took a couple of tries to start it again. I never had that issue. I have read that popping during deceleration is a "Lean" problem, is this correct!
 

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Detonation I mean "Popping in the exhaust"! The Air mixture screws are set at 2.5 turns out as per factory pro. Last night I took it for a ride and I noticed after it warmed up, it took a couple of tries to start it again. I never had that issue. I have read that popping during deceleration is a "Lean" problem, is this correct!

Popping can be a lean indicator but it more often indicates leaks in the exhaust system.
 

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Discussion Starter #6
How would I determine which? What about the trouble starting after it warmed up? Up until I put on the exhaust, I never had any of these issues.
 

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How would I determine which? What about the trouble starting after it warmed up? Up until I put on the exhaust, I never had any of these issues.

Difficult hot starting tends to indicate rich pilot circuits, or the chokes are staying on.
By "exhaust" do you mean the muffler or the entire exhaust system?
Try setting the mixtures back to what they were before you altered them?
 

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Discussion Starter #8
The exhaust is a full system. Its a full shotgun Devil system. The settings on the carbs were never touched. I put the Factory Pro kit on several months ago.
 
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