Bouncy idle speed? Help.

Hi all.
Riding about yesterday, after engined warmed nicely I stop at the lights and idle starts to bounce between 1300 and 1000 for about 20 seconds (sometimes continuous) then back to normal. Doesnt effect acceleration or cruising speed at all and doesnt cut out. This happened a few time on the journey home. Got home, turned engine off then back on and was fine. It isnt a major problem, just curious if this is normal or if something is wrong?

Could it be water? I washed my bike with a hose a couple of weeks ago.

[Speedy]

Possible water ingress to a sensor, but I doubt it.

Keep an eye on the engine temp (coolant temp) when it does this.

I'd be interested to see whats indicated......this is why:

If temp reading indicates a LOW reading, the ECU could think the engine is cold, making it run on "fast-idle". And vice-versa....so then when the coolant temp sensor reads correct again, sending correct info to ECU, the idle returns to normal.

Only a wild stab in the dark.

mine did that before the tps died the first time!

I'd put $$$ on a wet front plug

[Speedy]

Originally Posted by warrenhewitt10

mine did that before the tps died the first time!

Another possibility....TPS!!!

If the plug/HT lead had water contamination, the revs would surely die, as the engine would be mis-firing leaving only one cylinder running, which would also be under more load than normal.

I have the same bike as you, worth checking the front plug I haven't done yet simply as it hasn't become a huge problem but the revs have diped in wet. I'm sure there are loads of post about this.

Check the basic stuff first, however I'm sure the more knowlegeable people of the org will be able to offer much better advice I can.

working on a bike with no garage is no fun (garage for xmas please santa).
Wasn't able to remove the spark plug but pulled the rubber connector off. It was dry but saw some rust at the base of the rubber. Is rust a bad sign? Should I replace sparks?

Idealy you need to get the plug out and check the condition of both ends, clean up the plug cap and try it out, i dont know what to use on the connector of the cap but i managed to find some ignition drier in my work shop that my Dad got ages ago (think its as old as me!!) sprayed that on my plug cap connector and havent had a problem since

This bouncy idle happened again on Sunday's Toy Run! (thanks DB for pulling over to help out) This time it cut out when the revs dipped below 1000. Defo not water on the sparks. Could it be due to the engine hitting the 100 degrees? We had alot of waiting around at lights. Is this merely the bike saying "I'm getting hot, can we move faster please" ?

Originally Posted by Speedy

If temp reading indicates a LOW reading, the ECU could think the engine is cold, making it run on "fast-idle". And vice-versa....so then when the coolant temp sensor reads correct again, sending correct info to ECU, the idle returns to normal.

Only a wild stab in the dark.

"Fast Idle" is around 1800 RPM and "Idle" is 1300 RPM , the bike would not drop as low as 1000 if that were the case . His bike is sitting in Normal Idle position then dropping lower .

I had pretty much the same thing , I faffed about with Idle speeds and balanced the Throttle Bodies and played with the TPS . It turned out to be the core in the Spark Plugs breaking down . The plugs were the OEM ones and had done their fair share of mileage . Have a read of the thread here http://forums.sv650.org/showthread.php?t=128642 . I bunged 2 new plugs in and the problem never came back . Hope this Helps you out feller .