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Discussion Starter · #1 ·
So this problem has occurred twice, the first time no big deal was made since it was barely noticeable. Now it has happened again...the issue is when riding at high rpms my bike will beging to "jerk" around and slowly start decreasing in power. This happens in all the gears.
This is my first bike, it's 2012 with around 2400 miles. I bought it about a month ago from a person and it worked fine, including at high rpms.
I have some ideas of what it could be, but want to get it correct the first time.
Anyone had a similar issue and got it resolved?

I'll be attempting at fixing it myself if possible.
 

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Check to see if anything from under the seat hasn't blocked the air intake , a few guys on here have had that problem.
 

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This is similar to another thread not long ago.

In that case it turned out that the screen/filter/strainer inside the tank was partially blocked - with what exactly i don't recall - and it was starving for fuel when the demand was higher.
 

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Discussion Starter · #5 ·



So this is how the gas tank looks like, it seems to look fine, I tried moving stuff around and all seems sturdy and on its spot.
I took the front seat off and first off i found a comb, not mine so maybe previous owner. The air filter seems untouched and in good standing.

I've attached pictures to see if anyone can see anything out of the ordinary.
If it was a bad chain or sprockets, I would be getting the jerking motion throughout the whole ride, not just high rpms correct?

Thank you also for the feedback
 

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How old is the gas? Has it been sitting with a low level in the tank? Are you running ethanol-free?

Bad gas, or gas with a lot of condensation in it, will cause odd running problems.

Just to be sure, I might completely drain the tank and refill with the lowest octane gas you can find that doesn't contain ethanol. I'd also add a fuel system cleaner like Techron (my favorite - no surprise there) at 1oz per gal to the fresh gas.

You could also pull the plug and post a photo of it so we could see if it's burning correctly.
 

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Discussion Starter · #9 ·
I would run the bike every weekend for about 2-3 hours, and the gas would get refilled when almost empty. I put 87, since the manual says 86, but i haven't been able to find that around here.
Which plug are you referring to? I'm completely new to motorcyling, but very willing to learn all about it, main reason I would rather attempt at repairing the problem myself before giving up and taking it to a mechanic.

I gave it another run to further examine the problem, i cant reach red line since even before that it starts rocking back and forth, i did notice that if i ease into the speed i can pass 8-9k a bit more before it starts rocking, not sure if thats any helpful information.

I'll definitely go buy some Techron
 

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I would run the bike every weekend for about 2-3 hours, and the gas would get refilled when almost empty. I put 87, since the manual says 86, but i haven't been able to find that around here.
Which plug are you referring to? I'm completely new to motorcyling, but very willing to learn all about it, main reason I would rather attempt at repairing the problem myself before giving up and taking it to a mechanic.

I gave it another run to further examine the problem, i cant reach red line since even before that it starts rocking back and forth, i did notice that if i ease into the speed i can pass 8-9k a bit more before it starts rocking, not sure if thats any helpful information.

I'll definitely go buy some Techron
If you can, I would siphon the remaining gas out of the tank before filling with fresh gas and cleaner. Adding good gas on top of bad won't help you isolate the problem - just confuse the issue.

87 octane is fine. The manual recommends 86 or higher, but you will get the best performance with what you are using. Is it ethanol-free? The only reason, IMO, to go to a higher octane, or "Premium", fuel is to get away from ethanol. Use the lowest octane you can get without ethanol. Keeping the tank as full as possible most of the time will help reduce the chances of condensation (and eventually rust) forming in the tank. You could have a significant amount of condensation in the fuel - enough to give you the problem you have.

The spark plug sits on top of the engine with a good-sized wire running to it. It's condition and color can help you determine what the problem could be.

I would do the gas first, then if there's no change, pull the plug (engine cold). The tool kit should have a plug wrench in it, and I'd search around here for a quick "how to" if you aren't sure what you are looking at.
 

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Ok now the air box cover is off take it for a ride & see if it has the same problem, if it still does then this is where the fun starts, other things to check are,
Under the tank there is a filter( could be blocked )
To get to the strainer ( looks like a white sock attached to the fuel pump) you meet the tank off & remove the fuel pump to check.
Or do you know if the valve clearance was done? Could be out,
Or it could be a bad earth, sitting on the bike the main earth bolt is under the left side cover. Worst case if any of these things are out of your mechanical ability get it to a dealer or grease monkey to check out for you. Ride safe mate ;)
 

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Hi,

Same thing happened to me last week...when I was reving over 6000rpm, the engine was loosing power instead of further pushing the bike. In my case, the culprit was the air filter. I did a test (short distance) without the air filter and noticed that the bike is reving to the max. So, I bought a new air filter and now, the bike is like new.
 

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Had the same problem, Only someone had tied a party ballon over the pipe ;) Durex Are the bomb.
 

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Discussion Starter · #14 ·
Update for this still interested.
So I had done what I could and decided to let the experts take care of it, it was the kickstand sensor. I have not ridden it yet bc of bad weather but the sensor was broken due to someone dropping it before. The mechanic said it's fixed and I'm sure it is .
 

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thanks for the feedback of probable cause..
nice if you could take her for a good run now
over the same courses, with testing in mind,
and let us know how she went...
 

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That sounds odd. Wouldn't a faulty kick stand sensor shut the engine down completely?:confused:
Only if it failed completely. I can see a situation where a misadjusted (or faulty) sensor would cut the ignition of the kickstand were jostled from the fully retracted position a few percent over rough roads. As soon as the stand retracted fully once again, the engine would be good to go. If the bike were in gear and moving it would be the same as a bump start. This could happen many times in quick succession and act as a rev limiter.

Many Aprilia owners had a problem like this caused by the kickstand sensor.
 

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Only if it failed completely. I can see a situation where a misadjusted (or faulty) sensor would cut the ignition of the kickstand were jostled from the fully retracted position a few percent over rough roads. As soon as the stand retracted fully once again, the engine would be good to go. If the bike were in gear and moving it would be the same as a bump start. This could happen many times in quick succession and act as a rev limiter.

Many Aprilia owners had a problem like this caused by the kickstand sensor.
This, my neutral sensor was half connected and did weird stuff to the bike. So it's quite possible that the kickstand sensor was half killing the bike.
 

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Ah, the wonders of the vibrating single. :D
 
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