Bike cutting out / power loss whilst riding

Hi all,

I have had an Suzuki SV650 SK3 for about a year now however in the last couple of months I have been having (even more) issues with it.

Whilst riding the engine will completely cutout. By completely cutout, I mean that the engine will be completely silent and all vibration from the motor is gone and the rev counter will drop down to 0. There will be no response from the throttle however the speedo is still showing a speed, all be it one that is dropping due to loss of power. This will last up to a few seconds before the bike comes back to life as if nothing had happened. It started off very periodically however got more progressive until I got to the point where the bike was cutting out and going every few seconds so I had to pull over on the motorway.

I have also noticed that in lower gears (1st to 3rd) if I hold a constant speed (say 30 in second), the bike wont be smooth, it will jurk forward fairly often as if it is about to cut out but doesn't quite manage it before starting up again. It seems that I notice this first and as I keep riding, the issues escalate until it cuts out as mentioned above.

Now I have just had the bike serviced (and they also looked to see if they could find the source of this issue whilst they were at it). The work included amongst other things:

Spark plug replaced
Compression and Leak check
Removed, inspected and cleaned injectors
Balanced throttle bodies
checked valve clearances
change of air filter, oil filter and oil
replaced brake fluid
topped up coolant

Now whilst the service did make a noticeable improvement on how the bike performs, this intermittent issue is still there. The garage have taken the bike out for a combined 130 miles to try and replicate the fault so they can diagnose it but it seems every time they take it out, the bike is running smoothly?!?!?! They have said that if they cant replicate the issue, they won't know if any work they do on it will fix the issue.

I was wondering if anyone else has come by these issues and/or can diagnose it? Any help would be greatly appreciated as I have had nothing but issues with this bike and for once, I would just want it to run nicely for a while.

Ravi

[Tomor]

Have you checked the throttle position sensor? makes the running a lot smoother.

[Sid Squid]

Have the fault codes been checked?

I'm not so bike literate so I havn't really checked anything myself.

The garage did say when they looked at the bike originally that they thought it was the throttle position sensor however I can't see that anywhere on the invoice they gave me of the work they have conducted. I will have to ask them the question to see what they say.

And I have no idea about fault codes being checked. Again, I will ask the question to the garage. Is this something I could easily check myself?

[Sid Squid]

Search for the TPS setting thread, it will show you where to make the necessary connections to bring up the - limited, but still useful - self diagnosis and fault code display.

It may show nothing when running right, but could possibly point you in the right direction when it's not working right.

[Bibio]

sounds like classic side stand switch giving up or furred up connector even a loose side stand will cause issues so make sure that the springs hold it up with force and securely.

speedo will still register as you are still moving so you can rule out the green ignition connector as it cuts power completely.

Hi guys,

Sid: I will check out the post and report back, thanks for the heads up!

Bibio: Is it posible to disconnect the side stand switch to test whether it is the component at fault?

[Bibio]

i don't know where its an open or closed switch but i would presume its a closed type e.g. it makes a loop when in use. bridging the contacts of the loom plug will tell you if its a loop and bike should run with bridge in place. it's often overlooked as a problem source.

if it is a loop you could rig up a connector for a short while and try. if found to be the cause then replace it as i have seen people go bunny hopping because they have left the side stand down.

[ChrisCurvyS]

My side stand switch has cut in before on the motorway after it got loose and clogged up with grime.

It will normally happen when you hit a bump which causes the stand to jerk downwards - has that been the case?

[rictus01]

I agree it sounds electrical, I'd be bypassing all the cutouts, check all the multiplugs for corrosion, check the low coil feeds and any areas the loom that might rub, TPS shouldn't make it cut out like that, but if you're there; why not.

that would be my approach anyway

Cheers Mark.