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High speed power loss.

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Old Sep 26, 2018 | 01:20 PM
  #1  
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High speed power loss.

I may catch some flack for this but here goes. I was cruising on the freeway with a few friends that had CBR1K's and R1's, we were rolling along at 75-80mph. Saw an open stretch and decided to open the bikes up a bit, so I get the Hawk up to 130mph then back off to 95. Give it some gas and it struggles to produce power, almost like a vibration stumble is felt through the bars. I back off a bit more down to 80 and it smooths out, was able to at times hit 100 without an issue. Stopped at gas station, no oil leaks or fluids going on, idle is fine. Scratching my head.

76K mileage, oil change done about 1K miles ago. Been awhile for spark plug changes.
Old Sep 27, 2018 | 06:09 AM
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Is Full throttle acceleration in 1,2,3 perfectly normal, idle to red?
Old Sep 27, 2018 | 01:03 PM
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Fuel petcock diaphragm.

I had the same problem, rode well until a constant high speed was held then started to feel like it was starving for fuel. Back of and return to lower speed and all was well, idled fine , ran fine until a constant high speed was held.

This became worse over a long period of time so I pulled the petcock apart and the diaphragm was torn, replaced it and all is well.

Good luck.
Old Sep 27, 2018 | 04:21 PM
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I'm a simple guy...start from the simple...drain your float bowls.
Old Sep 28, 2018 | 10:03 AM
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Originally Posted by Wolverine
Is Full throttle acceleration in 1,2,3 perfectly normal, idle to red?
No issue there that I remember, I will ride this evening and make sure.

Originally Posted by kenmoore
Fuel petcock diaphragm.

I had the same problem, rode well until a constant high speed was held then started to feel like it was starving for fuel. Back of and return to lower speed and all was well, idled fine , ran fine until a constant high speed was held.

This became worse over a long period of time so I pulled the petcock apart and the diaphragm was torn, replaced it and all is well.

Good luck.
Hmmm..... I will check this out and see how the diaphram looks.

Originally Posted by YMRacing
I'm a simple guy...start from the simple...drain your float bowls.
I can do that as well. Asking because I don't know, why would the float bowls empty or full have an impact on performance?
Old Sep 28, 2018 | 10:13 AM
  #6  
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Originally Posted by ohiophotog
No issue there that I remember, I will ride this evening and make sure.



Hmmm..... I will check this out and see how the diaphram looks.



I can do that as well. Asking because I don't know, why would the float bowls empty or full have an impact on performance?
Might have water or "crud" in them.
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