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Discussion Starter #1
Hi
Just purchased a used 2016 Yamaha R1 with a Two Brothers S1R exhaust. Noticed that the bike's throttle response is very choppy and abrupt. Thought that the previous owner might not have flashed the ECU so took it to a tuner to get this done. Still having some issues with flat spots in the rpm and surging at certain rpms. Anyone had this issue or any suggestions how to resolve this issue?
 

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Is it any better than before getting it tuned? Might be that the tuner didn’t really do a custom tune but just pulled a generic map.

Is it a full exhaust or slip on only? Does it have an insert? If there is an insert you might have too much back pressure? Did the tuner open the valve and leave it open? Sounds like an air/fuel ratio issue.

To be safe, would also check your spark plugs.
 

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Discussion Starter #3
Hi
It is better then it was when I first got the bike. Low speeds were very hard to regulate in any mode. The Two Brothers is the slip on that eliminates the cat. It does have an insert or short pipe.
 

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Go see Nels at 2WheelDynoWorks in Kirkland. All your troubles will be resolved.
 

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in most of our recent experience a 'reflash' is only but the 1st step.. your bike is still not tuned.

most reflash now include a 'worked over' fuel map but it is not custom to your bike per-se.. you still need a proper dyno or live tune.

personally i'm much happier with results from using Auto-Tune / Power Commander V on top of the flash, but then I tune all 6 gears live while riding..

if you're unsure of how the bike was maintained though you can check sparks, also a kinked fuel line (very common in modern sportibikes)
could cause what you're describing. fuel lines are made of hard plastic with a cover, when the line itself gets kinked you cant really see it
but fuel flow is being disrupted, I tossed mine on the 09 R1. :happysq
 
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