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peplow
16-10-11, 11:53 AM
Hi all,

Right, where to start. I'm not into bikes, but my friend is and he's got a SV650S (the pointy version/fuel injection?).

I was round his the other day and he was showing me the bike and started it up, all was good. However it then started to splutter and cough so he revved it. I asked him why did it do that and he said that the engine dies ive he does not revv it when cold.

I got him to start her up again and leave it and sure enough, it died. Start up, bit of revving and she purrs like a kitten.

I asked him why it was doing it and his response was that V-Twins are renowned for doing this and its normal for and v-twin bike to die when cold like that. He backed this up by saying his mate has exactly the same problem on the same bike and is a renowned problem on the SV650's generally.

My response to that was somewhat different and id be banned from the forum if I repeated it so lets just say it was colourful. I did a comparison by saying that if his car did that, would he say the car had a problem and would you take it to the garage, as you can guess, his answer was yes.

He's got the fuel injected version (the pointy one) and not the twin carb (the round one) so Its not unbalanced carbs (at least not in a conventional sense)

Now my friend is rather lazy whereas im pro-active and have set myself the mission of proving him wrong that its "normal", getting him full power back and saving him some fuel money.

To be fair, the easiest thing is to get a diagnostics kit on it which may answer the question straight away but I just wanted to ask you SV650 owners if you have heard of this issue or known of common faults.

To me it sounds like the coolant sensor is either faulty, offset or has a flat spot at the bottom end but that's only my first stab in the dark but being as a few revs cures it, temperature does seem to be a strong evidence marker.

Cheers for looking and thanks in advance.

Mitch

MJC-DEV
16-10-11, 12:15 PM
My pointy is fine, something is definitely wrong as this is not normal for SV650S (engine layout makes no difference).
First: I would suggest check idle speed. If too low it may work at first through the FI added extra cold fuel until it starts to warm up and before reverting to normal fuelling.
Second: Check Throttle Position Sensor (TPS). full illustrated instructions on this site.
Third: Check air filter, clean or replace.

fizzwheel
16-10-11, 12:16 PM
What does he have the idle speed set at ? To low and it'll cut out as you describe. So try and adjust the idle speed so its set at the 1200 - 1300rpm mark and see if that cures it.

Cured a similar problem on my curvey and I also had the same issue on my GSXR after a mechanic adjusted the idle speed during one service. I turned the idle speed up and it cured the problem.

I'd try that first rather than fiddling around with sensors and diagnostic kits...

peplow
16-10-11, 12:52 PM
Cheers for the replies chaps, much appeciated.

Ive text my mate and have asked him to confirm what his idle speed is so ill let you know.

Out of interest (ill be honest, and lazyness) how do you adjust the idle speed on a bike? Is it just like adjusting the brakes on a road bike?

MJC-DEV
16-10-11, 01:16 PM
Using a screwdriver, turn the adjusting screw on left side of tank. Will be in owners manual.

peplow
16-10-11, 01:36 PM
Lovely stuff.

He replied, said its around 2500. I then asked for a serious answer to which he said 2500.

Turns out he has had a new throttle control sensor fitted. If its not been setup/calibrated and not seing the idle switch (assuming this is what hes reffering to) then the bike will be underfueling at what should be idle.

The question is, is it idling fast to mask another issue or is it purely because the throttle controller has not been setup? (or both)

Hes going to have a play with the idle speed today and let me know

MJC-DEV
16-10-11, 01:38 PM
Sounds like crap set up.

peplow
16-10-11, 01:47 PM
Sounds like my mate buying a pup and not wanting to give me the full story! :)

Is the throttle control sensor as it sounds, a variable input of say 0-10V on the twist throttle with an idle switch?

Sid Squid
16-10-11, 03:47 PM
Such antics are not a feature of owning an SV, (or any modern bike for that matter). The throttle position sensor most likely won't make a large enough difference alone to account for the 2500 rpm idle speed.

How does it run otherwise? Is it OK when it's hot? If yes then:

Set the tickover back to 12/1300 rpm when the bike is properly hot, (with the screw on the left side between the frame rails as said above).
What's the tickover like? Strong and steady, or rough and unreliable?

1. If it idles badly when hot then the throttle balance and TPS setting need checking, the try again.

2. If it's OK when hot, then turn it off and come back when it's stone cold, what happens when it's started then? If it won't idle when cold then the STV servo isn't working right. This could be the servo itself, a jammed linkage, the wiring to the ECU or a failure of the ECU itself.

peplow
17-10-11, 06:22 AM
Mornign Sid Squid.

Many thanks for the advice and feedback.

Its my mates bike so ive passed all your comments onto him and ill let you know when (if) he gets back to me.

Cheers again

Mitch