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Discussion Starter #1
I experienced this at a track day this past Sunday. Very un-nerving.

When rolling off the throttle setting up for a turn entry no doubt....

The Problem: When rolling partially off the gas the engine suddenly drops to around 1000 rpm. It happened twice on track. SUCKED. I was able to repeat it at the pit. Slowly run her up to about 6000 rpm, begin to roll her back down and BAM...drops to idle. Bring her back up to 5-6 K and roll slightly out again and BAM, idle speed.

I trailered her home and on monday evening figured I would have more patience and time. Started and warmed her up. Ran it up to 6000 and rolled back down without any problems. COULD MAKE IT DO IT AGAIN...ugh! I hate intermittent problems.
I can't in good faith take it back out there on the track not knowing that this is solved. Anyone had this happen? PS I have no FI code
 

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Discussion Starter #2
59 views and nobody has experienced this issue?

Cables all work fine and are smooth. has two brothers exhaust, but I do not have a PC or any fuel management device.
 

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Have you swapped out for aftermarket exhaust (full or slip on) or air filter? With no fuel management system, it might be causing you some issues.
But being it starts happening under 6k RPM, it might be an injector issue, because above 6k I believe the secondary injectors are active. Does it feel really sluggish under 6k when you ask it to accelerate?
 

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Discussion Starter #4
Have you swapped out for aftermarket exhaust (full or slip on) or air filter? With no fuel management system, it might be causing you some issues.
But being it starts happening under 6k RPM, it might be an injector issue, because above 6k I believe the secondary injectors are active. Does it feel really sluggish under 6k when you ask it to accelerate?
Hmmmm, secondary injectors are active above 6K huh. Well, that is very interesting. So, perhaps my primary injectors are failing to operate.
Do you know if the TPS controls these two banks of injectors?

*oh, and it pulls hard and smooth throughout the throttle. Not saying a good fuel controller and a tune wouldn't make it better. But, until this, she has been...well A HONDA.
 

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Hmmmm, secondary injectors are active above 6K huh. Well, that is very interesting. So, perhaps my primary injectors are failing to operate.
Do you know if the TPS controls these two banks of injectors?

*oh, and it pulls hard and smooth throughout the throttle. Not saying a good fuel controller and a tune wouldn't make it better. But, until this, she has been...well A HONDA.
I'm no mechanic (although mechanically inclined enough to do all my own work), so most of my information is gathered from things I've seen here. I'd have to assume the TPS is linked to the injectors because you have to connect to TPS and injectors when installing fuel management systems.

Give us some background on the bike. I remember seeing you're newer to the forums. People are helpful, but aren't going to hunt for the information.

What mods do you have? How many miles on the bike? Did you let it sit over the winter with gas in it? Have you disassembled the bike recently (potentially pinched a hose)?

Simplest place to start would be checking your air filter and trying to run a bottle of fuel system cleaner through. I prefer seafoam cleaner.
 

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Discussion Starter #6
G-Money, I have had it for about 7 months. Bought it so that I wouldn't crash my wifes on the track any more. Seriously. She was pretty hot about it last time!

Had to put her back to factory. New 520 kit, and that is about it. Ran her for about 4 tank fulls on street riding over the past 3 months. Then took her to the track. Issue happend once before lunch. Just thought is was a fluke. Then again MUCH worse after lunch in T13 at Jennings Grand Prix. I pitted on the next lap and was able to recreate the issue while sitting on the rear stand. Rev to 5+K. You can hold it steady. But as soon as you begin to roll back down....she drops to idle.

But now at the house, she won't do it again. I really don't like intermittent problems. I'm going to pull her apart next week sometime. It's Bike Week at Daytona, so we have plans to go there this weekend, and of course, for the 200 the following weekend.

Thanks for the ideas and suggestions thus far. I think I'm going to look for a loose connection or pinched hose when dissasembling. Was hoping that someone had "been there, done that" with this issue and could say..."Do BLANK, and BLANK. Also look for BLANK".
 

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A huge shot in the dark check the air vent hose off the bottom of the gas tank
 

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Okay, is this accompanied hy a severe drop in road speed? if this happens when you are rolling at speed and with the clutch engaged ( lever out) then there is either: a serious issue with your gearbox (randomly hitting false neutrals) or your clutch is slipping badly or your drive sprocket is slipping on its axle ( dont know if thats even possible)..

Engine speed should not just 'dip' while its mechanically linked to the rear wheel, the very least you'll experience severe engine braking if not rear lock-up..

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It's not a severe drop in speed this is caused by the servo valve I felt that condition all the time with Miss O'Seven when it was stock . Once I switched to an Akrapovic Full system which got rid of the servo valve but left the servo motor plugged into the ECU that condition of automatic engine braking upon downshifting went away it was annoying for sure
 

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Lets say you are in 1st gear near 12K rpm @ 60 mph, how can the engine drop to idle speed without pulling the clutch in or accidentally hitting neutral?

I think what you are refering to is momentary no response to throttle, giving you a feeling the engine is slowly dying away, but what he described is a dip all the way to idle, and thats on track, so rpm is prolly pretty high already...
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I was able to repeat it at the pit. Slowly run her up to about 6000 rpm, begin to roll her back down and BAM...drops to idle. Bring her back up to 5-6 K and roll slightly out again and BAM, idle speed.
Just noticed this, sorry moeman my bad.. To OP, something is off with your description, can you confirm it dropped all the way to idle while riding in gear? Or was it just bad throttle response?

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