SV650 Bogging down upon quick throttle response

[Redrose]

So I washed the bike and then got this issue, so my initial guess is that it's electrical. It's also an 09.

When I turn the bike on, all is as normal. I turn the key, the go to start it, to which it just about starts up (but i think my battery needs some juice, will put it on the tender tonight) and then idles totally fine, as usual. If I slowly add throttle, it's fine. But if I wack on some throttle with any speed. It seems to bog or will stall.

Also, it appears as if the STVA moves very jerkily and delayed to the action of the throttle. I think it's the STVA anyway. It's the bar that's the upper out of the two if that makes sense.

Also, when I turn it off, I get a weird ratchet/clicking like noise coming from below the airbox, maybe on the right hand side?

Also, any ideas if this will affect MOT? I have it in 2 days...

(Links to videos to follow soon!)

[Seeker]

The purpose of the secondary throttle valves is to maintain a constant airflow through the inlet manifold. If they're not working correctly a sudden opening of the throttle may (will?) cause bogging. The secondary throttle valves should move smoothly - maybe the linkage needs cleaning and/or lubricating or electrical connections to STV needs spraying with ACF50

Any c28 errors?


Here's an 09 SV video showing their dance: https://www.youtube.com/watch?v=2dkXIIf7U20

[Redrose]

The purpose of the secondary throttle valves is to maintain a constant airflow through the inlet manifold. If they're not working correctly a sudden opening of the throttle may (will?) cause bogging. The secondary throttle valves should move smoothly - maybe the linkage needs cleaning and/or lubricating or electrical connections to STV needs spraying with ACF50

Any c28 errors?


Here's an 09 SV video showing their dance: https://www.youtube.com/watch?v=2dkXIIf7U20

Thanks for the reply. I will take off the airbox then and have a look. And by linkage, I presume you mean the plastic ends which connect to each side? Do you think I would be able to test whether or not it is this which is causing my issue by either removing the connector that operates them so they're not being operated by the ECM and just hold, with my fingers, wide open while I rev the bike?

[Redrose]

And no error codes. Just _ C00

[Adam Ef]

You haven't got water in the front spark plug have you? Sounds like one cyclinder could be flooding flooding when opening the throttle, maybe due to a lack of a spark in the front cyclinder. It's possible for a bike to run with a cyclinder down but the ECU still to be adding fuel as if all is normal.

[Redrose]

You haven't got water in the front spark plug have you? Sounds like one cyclinder could be flooding flooding when opening the throttle, maybe due to a lack of a spark in the front cyclinder. It's possible for a bike to run with a cyclinder down but the ECU still to be adding fuel as if all is normal.

How will I know or how can I test if that’s the case?

[Adam Ef]

Pull the front plug. You'll have to unbolt the rad a bit to lean it out of the way. It's a quick thing to do to rule it out if it's not the problem. Is there a drain hole on the front cyclinder? Sometimes those get blocked up too.


I only mention it as a possibility as you stated the last thing you did to change anything was wash the bike. The other symptons don't sound like a spark problem. They may be coincidence now you're looking for something though.

[Adam Ef]

+ Does the front cyclinder / exhaust header get hot? Spray water on it to see... don't touch it!
Have you had the bike running long enough to get up to temperature or managed to ride it?

[DJ123]

it may be your airbox is not sealed on to the throttle bodies (the rattling you're hearing). And it's bogging down due to the flood of air coming in it can't measure.
Check the airbox is securely fastened down.

[SV650rules]

If it is the twin spark engine I am not sure how water in one of the plug recesses would affect it. Sounds like throttle body, but how washing it would affect that I don't know unless water has got into sensors, how high pressure was the hose you used ?

[Redrose]

Adam Ef: It's the twin spark model so could that still be the case with getting water in the front plug? And I will test to see whether it get's hot. I haven't had a chance to ride it yet as it's MOT is up and that is hopefully to get done on Friday.

daddyjob: Hmmm, would that be the case when i turn off the bike? It sounds much more mechanical/ratchet-y. Once my videos upload, I think it'll be much more clear.

SV650rules: I used a pressure washer but I wasn't blasting it. I more used it to mist off the soap. But it appears as if whatever I did was too much anyway. I seem to have no luck washing bikes, I had an R3 before which had electrical issues after I gave it a wash with just a bucket and soap.

I will update this thread once the videos are rendered!

Thank you for everyone's input! I really appreciate the help as i'm lost for this. I can follow instructions but can't diagnose the issues to easily.

[Redrose]

Here are the links to the videos:

Watching tachometer and throttle:
https://photos.app.goo.gl/rGC1U3RKn4WkbxFm7

Watching the connecting rod assemblies move:
https://photos.app.goo.gl/vmmBXPJDVNWw739G7

Ratchet-y click noise upon turning off the bike:
https://photos.app.goo.gl/x4a7YW17mL2dAthD6

[redtrummy]

It behaves in a similar way to how my SV was behaving - but mine is a 99 carb job. A mixture of Redex, fuel preserver and patience finally cleared it without too much trouble (blocked pilot jet?).
Is the upper connecting rod assembly running smooth as it should it seems to be slower, more jerky than the bottom one?
No idea what the bottom clip noise is

[Redrose]

It behaves in a similar way to how my SV was behaving - but mine is a 99 carb job. A mixture of Redex, fuel preserver and patience finally cleared it without too much trouble (blocked pilot jet?).
Is the upper connecting rod assembly running smooth as it should it seems to be slower, more jerky than the bottom one?
No idea what the bottom clip noise is

I had a look at some videos online and mine doesn’t seem smooth at all compared to others. So I’m not sure if that’s the issue or a potential secondary effect of the actual issue. I don’t really know what to test or where to go from here.

[Adam Ef]

Clip 1: Seems to cut out very quickly. If that's how it happens every time rather than a spluttering and fade I'd say it's less likely to be a flooding / fuelling /spark issue.


Clip 2: Delayed, sticky action / out of sync doesn't seem right.


Clip 3: I think I remember my SV sounded like that and was ok.


As a twin spark it is unlikely to have an issue with soggy plug (videos wouldn't suggest that is the problem either), but I'd be ruling out as many things as possible to narrow it down. It looks like one of those problems where a process of elimination is needed.


I'm guessing you haven't managed to get it up to temperature then? Trying to rule out a problem from washing it.. if it's moisture got in somewhere it shouldn't often just getting up to temperature and getting heat through the bike to evapourate dampness can help. If you can't get it to run at all then that won't work though.


It's just a hunch but the sudden cut out in the first video does suggest something electrical to me. If it was fuelling or air it would splutter more. Fuelling would be more random too. Have you pulled electrical connectors and checked them under the tank? The linkage in the second video seems dubious too. Have you lubed the linkages?

[Redrose]

Okay. So I’ve ended up lubing the linkages and that isn’t the problem. I also disconnected the motor responsible for controlling the butterfly valves while the bike was running. Opened the butterfly valves to about half way and gave it a few blips. The same problem is persisting: it bogging down, so I don’t think it’s an issue of the STVA?

And I haven’t managed to get it up to temp or ride it around. Not because it won’t, but because I don’t have an MOT at the moment (hopefully will tomorrow). I’m currently just letting it sit and get warm while idling.

I found that when I took the air box off and disconnected all the plugs. One of them had a bit of fluid in it, maybe water. I dried all of it off but still no improvement.

[SV650rules]

I have had problems with carbed bikes with refusing to respond to a quick throttle blip, but that has been blocked jets, with an injected engine it may be gunged up injectors, try a good overdose of redex petrol injector cleaner ( don't mess about put a whole 250ml bottle in ). Otherwise have you tried opening the fuel filler cap and revving the engine ? long shot but may be a blocked breather. Is there a fuel filter ? may be blocked up.

[Redrose]

So, the bike ends up responding better when it’s up to temperature and it won’t stall no matter how hard I blip the throttle but the problem is still there.

And SV650rules, that’s a good shout. I’ll try that and I’ll also pop in shells premium fuel as apparently it also does a good job at cleaning.

[redtrummy]

What I did was to have a small amount of petrol and a good dollop of redex in the tank (plus I had added fuel preserver to the petrol). I ran the bike over a couple of hundred miles , topping up with a little petrol and more Redex - my theory was that the rich Redex mixture would be lying in the carb when not in use and might soften the blockage. I gave up when there was no apparent improvement and arranged for the carbs to be stripped down. On starting the bike a couple of weeks later prior to having it seen to it ran as sweet as a nut! Not sure its relevant to your situation but it may help someone else

[Redrose]

So i think i've narrowed down that clicking noise (in the 3rd video) to the PAIR valve.

[Redrose]

I'm browsing through the service manual for the bike and have noticed that during the C00 error code, when the bike isn't running, the TPS position is on the lower (_) out of three options and it's supposedly meant to be in the middle (-)?

I wonder if that's potentially part of the issue.

https://imgur.com/falrDwl

[Adam Ef]

TPS sensor is often out of place. It's very sensitive to adjust. You need a security torx bit / key. There was a thread on here about it and setting it a while ago. If you adjust it my advice would be tiny taps on it with the torx bolt still mostly done up, as when you tighten up the torx bolt it is so sensitive the tightening adds adjustment to what you've already done. It can be a bit trial and error.

[aesmith]

I'm browsing through the service manual for the bike and have noticed that during the C00 error code, when the bike isn't running, the TPS position is on the lower (_) out of three options and it's supposedly meant to be in the middle (-)?
Yes, it's supposed to be in the middle when the bike's idling, and try and set it so it goes "up" almost as soon as the throttle's opened. Check slowly, the display only updates every 1/2 second or something.

[Adam Ef]

When I checked mine it was about 4k revs before the dash moved up. Common problem apparently. Took a few attempts to get it move up just above idle.

[aesmith]

I think part of the problem is that the TPS is on the rear throttle body, rather than the one directly controlled by the throttle cable. So it's dependent on any backlash in the linkage, and also means it will need to be reset after TB balance has been adjusted. I think on the original pointies it gets messed up if you change the idle speed as well.

[Adam Ef]

Plus, on a K9 you need to lock the idle with the dealer or Healtech tool as it's auto idle if you want to balance the throttle bodies. That's the stage I got to with my K8.

[aesmith]

At MOT last year I got the dealer to check valve clearances and balance TBs. I completely forgot about the effect on TPS until I was messing around and set Dealer Mode for another reason. It was way off.

[Adam Ef]

They're often set quite high from new.