Fast idle issue

[tom_e]

I've noticed recently on my SK5 that when I start it up the idle will jump up to around 2k rpm which is normal for my fast idle then drop for a few seconds to around 1.3-1.4 then go back up to 2k until it's warm and then it'll settle at the correct idle speed that I've set.

Also I noticed if I try and rev it during this time it's very slow to react and even an almost full twist of the throttle won't get it higher than around 4k again a few seconds later and it's fine and will rev freely with the throttle.

Does this sound like anything major or worth worrying about?

The only things I can think that may affect this that I've changed are fitting a K&N filter and removing the snorkel, although I don't remember these issues when those items were first done.

[russell664]

I had this on my Curvy, I think it is related to the cables being too tight, and not freely moving.

Start it, and move the steering lock to lock, does the RPM change then?

[tom_e]

I'll give it a go when I finish work but I can't see it being the throttle cables as like I say if I leave it a couple of seconds without touching anything it'll settle into the correct fast idle RPM and rev freely when I twist the throttle.

I doubt it'll be that too mainly because the pointy has electronic injection with fast idle etc, the Curvy didn't.
Also the pointy has a return throttle cable too, I don't think the curvy had one.

Sounds like a problem on the butterflies to me, they have been known to get dirty and difficult to move, might be worth a quick clean up?

[Bibio]

sticky tickover lobe or electrical. make sure that the battery terminals are clean and tight.

when were the spark plugs last changed?

[tom_e]

Originally Posted by Corny Gizmo

I doubt it'll be that too mainly because the pointy has electronic injection with fast idle etc, the Curvy didn't.
Also the pointy has a return throttle cable too, I don't think the curvy had one.

Sounds like a problem on the butterflies to me, they have been known to get dirty and difficult to move, might be worth a quick clean up?

This would tie in with it generally feeling a little slower off the mark and not quite as perky as it has been wouldn't it?

If so it looks like I know what I'm doing this weekend.

Plugs were last changed in december so around 5-6k ago for some Iridium ones.

Possibly yes, I maybe wrong but thats what id check first. I doubt the little motors that move the butterflies have much power behind them so any buildup and gunk etc will become apparent quick.

I think the STV is actuated by motors based on your throttle position so if these are moving slowly then yes it wont be as perky.

Again this is just stuff I remember reading on here. Good luck

[Craig380]

This thread is worth a look - a while back I did all the pivot points and linkages in the main and STV throttle linkages & pivots with a drop or two of light oil for electric motors (safe on plastics) and the throttle action is a lot smoother as a result.

https://forums.sv650.org/showthread.php?t=220760

[tom_e]

Cheers Craig that was beginning to be my thinking after some searching so I'll give it all a go tomorrow if it's dry. Already gave it a general squirting with gt85 without lifting the tank when I got home so we'll see how it fires up tomorrow.

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[tom_e]

Took the air box off this morning first things first I obviously got a little over excited oiling my air filter before I fitted it as there was a little puddle of filter oil in one corner so cleaned that out then gave all the throttle body pivots a good soak in gt85 then a final squirt of acf50 all round. Fast idle seemed smoother after that but it may be because I'd started it up once or twice before I finished so it may just have freed everything up. Fingers crossed when I start it up tomorrow after it's sat overnight it'll still be good or else it's time to look elsewhere.

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