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Discussion Starter · #1 ·
To the guru’s! I need some help!
I Just got finished my 5th trackday with my ‘08 RR. Something odd happened towards the end of the day on the track. On wide open throttle in 2nd gear (on the straights) the bike would rev to 11,500rpm and hold that rpm for a few seconds before finally revving past and it still didn’t feel like the same acceleration once it passed 11,500 up to redline. Motor is stock but has a Yosh slip on and power commander 5. No engine lights or
change in oil level. No noticeable leaks anywhere.
I remember hearing some more metal “tapping” near the left side gear shift rod when it was idling after I came off the track. Called it quits and came home before something worse happened.
cheers and thx for the help in advance!
 

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Discussion Starter · #4 ·
I had a closer look at the bike and the metallic tapping seems to be coming from the exhaust area under the bike where the servo is located?
I know there is a “skutrnet” module installed on the bike to trick the ecu into thinking it’s still there.
 

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Discussion Starter · #6 ·
so first gear you can achieve 15k?
I didn’t get to try 1st - something about redlining 1st doesn’t sit right with me lol.
I took apart the “flapper” in the exhaust and found a small broken metal tab from the unit. Since it was rattling at idle, I can assume 100% this is my problem. The flapper can now move as it wants depending on exhaust gases.
 

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Yes, flapper is supposed to be wired open if disconnected....if free movement, odd that it maybe is closing at high rpms.

If you use an MJS mid pipe you can remove about 12 lbs of ugly fat.....but bike may need a PC5 and a dyno tune after cat removal....maybe not permissible if you still want road riding.
 

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Discussion Starter · #8 ·
Yes, flapper is supposed to be wired open if disconnected....if free movement, odd that it maybe is closing at high rpms.

If you use an MJS mid pipe you can remove about 12 lbs of ugly fat.....but bike may need a PC5 and a dyno tune after cat removal....maybe not permissible if you still want road riding.
Thanks!
How do I know where to wire the flapper fully open? I can’t actually see it in the exhaust.
Cheers!
 

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That sounds a whole lot like a gas, fuel filter or fuel pump issue so I'd run some know good gas through it and see if that changes anything to start. As far as the left side tapping you have the stator and water pump rotating and you could have something loose and vibrating (ex: shift linkage).
 

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That sounds a whole lot like a gas, fuel filter or fuel pump issue so I'd run some know good gas through it and see if that changes anything to start. As far as the left side tapping you have the stator and water pump rotating and you could have something loose and vibrating (ex: shift linkage).
I can confirm that there is a strainer on the bottom of the fuel pump that can become clogged and limit your rpm to 11k as fuel flow is interrupted. For the age of the bike I would open up the fuel pump and replace the strainer. Clean the tank with some screws or bbs and gas rinse it. There is a fuel filter built into the pump housing discharge. You can order a new strainer off of amazon for like $10. The tank probably has rust for its age. Worth checking out.
 

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Discussion Starter · #11 ·
That sounds a whole lot like a gas, fuel filter or fuel pump issue so I'd run some know good gas through it and see if that changes anything to start. As far as the left side tapping you have the stator and water pump rotating and you could have something loose and vibrating (ex: shift linkage).
Thx!
I ran a full session (20 mins.) in yellow group with a fresh batch of 10L of 93 (highest grade they had) - no problems.
 

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Discussion Starter · #12 ·
I can confirm that there is a strainer on the bottom of the fuel pump that can become clogged and limit your rpm to 11k as fuel flow is interrupted. For the age of the bike I would open up the fuel pump and replace the strainer. Clean the tank with some screws or bbs and gas rinse it. There is a fuel filter built into the pump housing discharge. You can order a new strainer off of amazon for like $10. The tank probably has rust for its age. Worth checking out.
Thx for this! I’m really hoping to limit the problem to just the flapper in the exhaust as it is clearly making the metal rattling at idle. (Bolt play is loose).
It’s interesting to rotate it while it is idling. There is a very distinct change in the sound of the engine for obvious reasons. I would like to think that at WOT the flapper would just open as far as it can and stay that way due to the velocity of the exhaust gases.
Cheers
 

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My flapper valve was rattling also. I took an angle grinder and chopped the ends of the shaft off, removed the flapper and welded the holes up.
 

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Discussion Starter · #14 ·
My flapper valve was rattling also. I took an angle grinder and chopped the ends of the shaft off, removed the flapper and welded the holes up.
Did you have to remove the exhaust to get the flapper out after you cut the ends off?
Did you take the headers off or the midpipe to do this?
 
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