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Discussion Starter · #1 · (Edited)
Hi there!
I just picked up my SV 650s 2004 from the dealership, and i absolutely LOVE it. So much fun! It only has 13k km on it (8k miles)

The only issue i'm having, is that sometimes the idle rpm seems to become a bit unstable. Could it possibly be an electricity issue?
It seems to happen regardless of how hot the engine is. I've been doing some more testing, and it appears that it only happens at higher temperatures, after a longer ride.
Heres a video of it
Thanks in advance for any input! :)
 

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did this occur before the dealership touched it? I've got the same bike and it idles perfectly at 1300. It simply could be a fuel problem, ie stale gas, could cause a varnish problem with the injectors.
 

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Discussion Starter · #4 ·
Yes. ‘Just’ picked it up from the dealership? Take it back to them. Unless you bought it ‘as-is’, and sometimes even then, it should be covered by a consumer warranty.
Unfortunately it is a bought as "as-is"
I'm hoping it's not a big problem and just a quick fix. Might swing it by a mechanic for a service soon.
 

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Wehlast, if the bike has been bought from an official dealer (I mean you didn't buy it from a private owner), according to european laws (I guess from the flag under your avatar you're from Denmark) the bike is covered against hidden defects for a period of 3 months.
Might be worth checking.
 

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I have an '04, had an issue with "hunting" rpms for years. Other symptoms were poor fuel economy, bike dying after an hour ride at highway speed with smell of unburnt gas (flooding). Tried so many things to fix it.

I'm not sure, but for me, the possible fix was cleaning the injectors. Funny thing is, I had them properly (professionally) cleaned at a fuel injection shop years ago. This time I took them to a local auto shop where they sat on the shelf for a few weeks. I got fed up with the shop's inaction, took them home, and sprayed them down with carb cleaner. Didn't even do a proper job, just sprayed the surfaces. For the life of me, I can't see how that could have helped, but it did. Symptoms were gone.

An '04 with only 14,000 km. means it hasn't been ridden a lot. It could have been sitting for long periods of time, leading to "varnish" (circabob) or dirty injectors.
Fuel filter clogged? Shouldn't really affect idle, I would think, only higher revs.
Presumably you've already put a few tanks of fresh gas in it (based on the mileage in your video) so old gas shouldn't be an issue (?)
I chased the malfunctioning coil theory (symptoms show only when they get hot) but did not lead anywhere.

Let us know how it turns out!
 

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Discussion Starter · #7 · (Edited)
I have an '04, had an issue with "hunting" rpms for years. Other symptoms were poor fuel economy, bike dying after an hour ride at highway speed with smell of unburnt gas (flooding). Tried so many things to fix it.

I'm not sure, but for me, the possible fix was cleaning the injectors. Funny thing is, I had them properly (professionally) cleaned at a fuel injection shop years ago. This time I took them to a local auto shop where they sat on the shelf for a few weeks. I got fed up with the shop's inaction, took them home, and sprayed them down with carb cleaner. Didn't even do a proper job, just sprayed the surfaces. For the life of me, I can't see how that could have helped, but it did. Symptoms were gone.

An '04 with only 14,000 km. means it hasn't been ridden a lot. It could have been sitting for long periods of time, leading to "varnish" (circabob) or dirty injectors.
Fuel filter clogged? Shouldn't really affect idle, I would think, only higher revs.
Presumably you've already put a few tanks of fresh gas in it (based on the mileage in your video) so old gas shouldn't be an issue (?)
I chased the malfunctioning coil theory (symptoms show only when they get hot) but did not lead anywhere.

Let us know how it turns out!
Nice to hear you found a solution - even after a few years! Based on the video i posted, did your SV behave the same as mine?

I've just cleaned the air filter, replaced both spark plugs and filled up some injector cleaner liquid in the tank. It's late here, so I haven't been able to test it yet, to see if that has fixed anything.
I think the next step if that doesn't fix it, is to adjust the TPS. I'll attempt that tomorrow! Judging from my google searches, that could also be the issue. If that doesn't work, I might just try the same as you did :)
 

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The TPS adjustment is to fix a jerky throttle at low RPMs. It won't fix the fluctuating idle, but is recommended at some point for smoother riding at low speeds.

I had a similar issue after not riding my bike for over 8 months using the old gasoline that was not stabilized. Ethanol in the fuel binds water over time, and when that runs through the fuel system it creates the "hiccups" you have. In my case it lasted about 20 miles and was fine afterwards. After having run two tanks of fresh fuel through the engine it purs like a kitten again.

Modern fuel (especially mid-grade or premium) has enough detergents to do a good enough job cleaning your injectors. However in your case, there might be some varnish and blockages from fuel that sat stale for multiple years in the tank and lines. If it was not stabilized and contained Ethanol it may have also attacked the fuel lines. Also check the inside of the tank for rust (since Ethanol attracts water it may lead to corrosion quicker).
Those are the main problems with old low mileage bikes (well, also change the fork oil out, which the dealership definitely hasn't done since it's not listed as a scheduled maintenance item but should be done every two years).

As a quick fix I'd also suggest to have the injectors professionally back flushed and maybe replace the fuel lines.
But the cheapest method is to just ride it a lot and at length. A couple of multiple 100km day trips may work wonders to restore the health of your fuel system. After 18 years of mostly standing still it deserves some proper long rides. The more you ride your SV, the happier it will be (mine is approaching 100k km and as agile as ever). 😎
 

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Discussion Starter · #9 ·
You might have had a point there @sv650bklyn and @circabob
The issue seems to have disappeared today - I don't think it's due to me changing spark plugs/cleaning the air filter. The air filter was already pretty clean. Probably just coincidental that the issue went away after that.
I also think the problem occured due to old fuel in the system. The bike had 8450 miles on it when i picked it up, and 8700 now. Almost 2 full tanks of fresh fuel, might have just done the job! Thanks for your input :)

I'll still try the TPS adjustment later on, as I think it is a bit rough at lower speeds, suddenly gaining power at 3-4k rpm.
 

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Heh. @neimis ’ fix probably had more to do with the bike just sitting for weeks rather than spraying the injectors. It’s funny how those things go! 😄

Like your issue disappearing. I looked it up, and these bikes seem to have an Idle Speed Control (ISC) valve. This is usually just a little stepper motor that, when it fouls up, will cause exactly this issue. The ECU tells the valve to raise the idle by opening, which it does! Too much. So the ECU then says to adjust it back down by closing, which it does. By too much. So the process endlessly repeats…

@Skywalker67 , here in Canada, that warranty even extends to private purchases. Even when explicitly stated ‘As is, Where is’ on the receipt! Most European countries have even stronger consumer protection laws than we do, so it would be worth checking into… If the issue comes back. 🤞
 

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Discussion Starter · #11 ·
Heh. @neimis ’ fix probably had more to do with the bike just sitting for weeks rather than spraying the injectors. It’s funny how those things go! 😄

Like your issue disappearing. I looked it up, and these bikes seem to have an Idle Speed Control (ISC) valve. This is usually just a little stepper motor that, when it fouls up, will cause exactly this issue. The ECU tells the valve to raise the idle by opening, which it does! Too much. So the ECU then says to adjust it back down by closing, which it does. By too much. So the process endlessly repeats…

@Skywalker67 , here in Canada, that warranty even extends to private purchases. Even when explicitly stated ‘As is, Where is’ on the receipt! Most European countries have even stronger consumer protection laws than we do, so it would be worth checking into… If the issue comes back. 🤞
If the issue returns, I might have to look into that! That's a good point. I'm not sure how the issue fixed it self - still worried that it'll come back, hehe.

And yes - I could possibly swing the bike by the dealership. The reason I haven't done that, is because I purchased the bike at a dealership a few hours away from my home. Would just be ideal if I could resolve it myself :D
 

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It is not the ISC valve. That is on the SV650 2007+ only. 2003 to 2006 have manual idle adjustment.

The TPS adjustment won’t cause this problem, but if the TPS sensor potentiometer contacts are flaky, that could cause intermittent uneven idle. If the problem comes back, try lightly tap the TPS sensor to see if that alters the symptom.

A more conclusive test is probe the TPS sensor wire with a voltmeter to see if the sensor voltage changes in sync with the uneven idle. If the throttle is not moved, the TPS sensor voltage should be rock solid.

I would leave the TPS adjustment alone for now. If you do touch it, make a scribe mark so you know where it was set to originally. The TPS adjustment can be touchy.

Good luck. Intermittent problems are a pain.
 

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Try cleaning the sparkplug drain hole for the front cylinder. Halfway down rh side of front cylinder, poke hole with a piece of stiff wire or a thin screwdriver etc. Dealer will probably have washed bike, if the drain hole is blocked, the front plug tunnel fills with water and shorts the plug cap. if you have some wd40 or even compressed air try using that once the hole is unblocked.
 
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