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TOPIC: Power-pulsing at high revs?

Power-pulsing at high revs? 4 months 2 weeks ago #117006

  • xplorer
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On Saturday I took my 2012 KLR to the bike track day at Killarney race track.
Something strange happened that I did not have time to ponder in the moment, but now its bothering me.
Approaching the end of a short straight with wide open throttle in third gear, I was about two seconds from the point at which I would transit from maximum acceleration to braking hard for the corner. The revs were approaching the red but gearing up was not an option at that moment, so I decided to continue at WOT. Suddenly I experienced what felt like a rev-limiter kick in, with the power pulsing quite aggressively. I stole a quick down at the tacho and estimate about 8200RPM or thereabouts, but not absolutely sure as I was being crowded by a few other much faster bikes and the workload was a bit high with a lot happening very quickly. I immediately rolled off the power and the engine immediately felt normal again.
That was during the second of four sessions, and it did not happen again the rest of the day, probably because I was too concerned about what happened and made certain I stayed under 8000RPM after that experience.
I think that was my 8th lap out of about 34 for the day.
I have done another 185km since then and the engine seems fine.
I very much doubt that the KLR has a rev-limiter.
Or am I mistaken?
What else might cause that sensation of power pulsing at high revs?
Valve-spring resonance?
Valve-bounce?
Anything to be concerned about?
Is there anything I should check?
Am going to the Thumper Bash near Ladismith 10-12 August and don’t know if I should be concerned about my engine after that experience or not.
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Last Edit: 4 months 2 weeks ago by xplorer.
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Power-pulsing at high revs? 4 months 2 weeks ago #117007

  • capeklr
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xplorer wrote:
Valve-spring resonance?
Valve-bounce?

Most likely valve bounce.
I hope that there is still some oil left in the engine.
I would recommend a oil change before the long trip.
Fresh brake fluid as well front and back.
"The world is a book and those who do not travel read only one page."
St Augustine
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Power-pulsing at high revs? 4 months 1 week ago #117008

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capeklr wrote:
xplorer wrote:
Valve-spring resonance?
Valve-bounce?

Most likely valve bounce.
I hope that there is still some oil left in the engine.
I would recommend a oil change before the long trip.
Fresh brake fluid as well front and back.

Can valve-bounce cause any damage on the KLR?

Oil change already scheduled for this weekend.

Brakefluid replaced very recently.
Keen to meet and ride.
082 414-8448
If you are in Cape Town, message me to join our WhatsApp group for organising meets and rides.
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Power-pulsing at high revs? 4 months 1 week ago #117009

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xplorer wrote:

Can valve-bounce cause any damage on the KLR? Any motor can get damaged from valve bounce and the results might only show themselves at a later time.

Oil change already scheduled for this weekend. Good.

Brakefluid replaced very recently. Replace again, the brakes will have got very hot on the track so the chances that there is moisture in the brake fluid now is very high.
"The world is a book and those who do not travel read only one page."
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Power-pulsing at high revs? 4 months 1 week ago #117010

  • Dieseldawie
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Sell the KLR and buy a track bike. That is not what it is made for. Try to keep under 5000rpm at all times

You will blow it up eventually.
I like to drink lots of beer??
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Power-pulsing at high revs? 4 months 1 week ago #117014

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Dieseldawie wrote:
Sell the KLR and buy a track bike. That is not what it is made for. Try to keep under 5000rpm at all times
You will blow it up eventually.

I have no intention of racing the KLR. It will lose against even the 300cc racers, lol.

I took to the track to gain more experience with cornering at speed in a safe environment. No cars, taxis, pedestrains, livestock, wildlife, gravel, water, oil, etc.

Unfortunately I found most of the straight sections too short for the sluggish KLR to accelerate up to the speed that I wanted to approach the corners at, so I had to work the engine hard to achieve realistic speeds into the corners.

Even with the 16 tooth front sprocket, a KLR is going to exceed 5000RPM at normal everyday highway speeds, so its unrealistic to try keep under 5000RPM.
I tried a 38 rear sprocket but then it was a dog on the dirt, just not enough torque on the rear wheel.
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Power-pulsing at high revs? 4 months 1 week ago #117029

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KLR is not really made for "Normal Highway speeds" 16t front means around 125kmh at 5000rpm. and even keeping that up for hours at a time will not do it any good. Buy another bike for your highway commute and keep the KLR gearing standard for the dirt and trips which it what it was made for.

I see that Dux from Motoworx said KLR does have a rev limiter built into the CDI??
I like to drink lots of beer??
Last Edit: 4 months 1 week ago by Dieseldawie.
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Power-pulsing at high revs? 4 months 1 week ago #117031

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Dieseldawie wrote:

I see that Dux from Motoworx said KLR does have a rev limiter built into the CDI??

Very interesting! I would not have imagined that in my wildest dreams!

In a Google search now, I also saw an advertisement for an aftermarket KLR650 CDI that "raises the rev limit by 1000 rpm". That sounds like a stupid idea, though! :laugh: :laugh:
Last Edit: 4 months 1 week ago by Piet.
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