Unsettled idle revs when engine is warm

[bat-kam]

My wee was coming to 18k service so I went ahead and changed oil, oil filter and spark plugs.

Before the plugs were changed when the engine was started in the morning the idle was very unsettled and it sounded as if the front cylinder wasn't firing properly. Once the engine was up to its operating temperature (3 bars) it had perfect steady idle revs.

Two rear plugs were in OK condition


But the front plug was in far worse condition


And the front side one  wasn't that good either


Since plugs change the idle when the engine is cold is very nice. However, when the engine is up to it's normal operating temperature the idle is a bit nervous. It should hover around 1,3k rpm but it jumps up to 1,5k rpm and then comes down to almost 1k rpm or 1.2k rpm.
I should add that after a minute or so on idle it settles down to the range between 1,3k rpm and 1.4k rpm.

I understand that I shouldn't be very picky and look for silky smooth inline 4 but it should be better then it is at the moment, right?

I was thinking of the valve clearance but Keith, who I bough the bike from, was a bike mechanic for years and been doing the service himself so this shouldn't be a problem.

Is there a way of resetting the memory of ecu?

Or is there something else that I am missing?

Thanks for all the advice in advance

Kam

[greywolf]

The plugs don't change the idle. Did you mean since you changed the plugs? The ECM controls the idle through the ISC valve and has not been user adjustable since the 2007 model year. When cold, the idle may be as high as 1800rpm. It should quickly drop down to a steady rate at about 1300rpm as the engine warms. The front plugs can get dirtier on the outside because they are more subject to splashing in wet weather. The center plug is pretty much sealed by the rubber cover fitting against the engine though. Your front center plug looks like the cover was loose and allowed water inside.

Some adjustments can affect the idle speed so there is a reset procedure. See my post #4 at http://www.stromtrooper.com/v-curious/6 ... 650-a.html

Your speed doesn't seem off though.

[bat-kam]

As always greywolf with quick response ;)

I am aware of the initial rpm when engine is started. What I meant was after it comes down, then it was unsettled.

Bike seams to pick up speed OK, although when in 2nd and 3rd gear I can feel the jerkiness up to 4k rpm

[greywolf]

I added a reset procedure by an edit. I don't think that will change things though. Are you sure the plugs are properly torqued and gapped? Are the caps tight?

[MartinW]

Kam - You have the wrong bike model year in your profile, so need to change that and then confirm the responses are valid for your bike.
 

[bat-kam]

Sorry, my profile has been updated. I am talking about wee 2010 model

[greywolf]

My responses are applicable to all four spark plug 650 V-Stroms to the present date.

[bat-kam]

I have just ordered feeler gauge so once I receive it I will check the gap. For now I have to assume the when they are new they are gapped correctly.

Torquing I did by hand.

[greywolf]

Unless the plugs got dropped, their gap should be okay. I don't know how good your feel for torque is. If the idle was okay before, a change is most likely from something you did. The tank had to come off to access the rear plugs. Make sure the moving parts on the throttle body aren't contacting anything. Doing the reset procedure wouldn't hurt.

[bat-kam]

It has been a while since last comment on this topic.

After a reset of IDLE rpm suggested by graywolf, nothing has changed with the engine. I got used to it.

Riding to work today, I felt significant lack of power on few occasions. Only for a second or so. Both times at low speed, once in 2nd gear pulling out of a T junction @ 12 mph (throttle was set but power disappeared for a split second) and second time 10 minutes in the ride in 3rd gear @20mph (throttle set but few jerks as if the engine was going to cut out). The engine wasn't even on one bar warm.

I will take a short video clip an put it on youtube of the revs.

Any suggestions?

[Juvecu]

Some coil packs can start giving intermittent spark once they are warm. It's difficult to test for though so make sure you check other obvious things first before you decide to try replacement of these. Coils failing isn't a common thing, just a possibility.

[bat-kam]

Here is a short video clip

[Firestorm]

This might sound a bit odd but have you had a good look under the tank and at the plug caps in the dark? There appears to be a 'ticking' noise during the close up at the end of the video and it sounds a bit like a stray spark.
Start the bike at night away from any light sources and have a good look around. You may be lucky. Its also free to try!

[geekay]

if it was me, the first thing I'd do is put the std exhaust back on - in my experience, rough running is almost hand in hand with open exhausts - unless the aftermarket exhaust is quite restrictive also and / or it has been well set up to take account of the aftermarket part.

also - difficult to tell, but the variable idle - the engine note doesn't seem to change to my ear - it couldn't just be a bad connection to the gauge - or some other instrumentation issue could it?

[bat-kam]

Firestorm - that is a good tip. I will try this in the nearest future. The ticking noise was worse before I changed the plugs and oil.

geekay - with the original exhaust on it was the same if not worse :( But I just may give it a go after I try the firestorm test.

[geekay]

Firestorm - that is a good tip. I will try this in the nearest future. The ticking noise was worse before I changed the plugs and oil.

geekay - with the original exhaust on it was the same if not worse :( But I just may give it a go after I try the firestorm test.

fair enough - but if the original is 'worse' might this indicate a gas-flow problem (at one end or another) rather than a spark issue?

[bat-kam]

I started the bike in closed garage with covered lights and I could not see any electric sparks jumping around the engine or the plug wires.
Though that ticking/clicking noise was around the front cylinder as soon as the engine wormed up to working temperature.
Could it be coil?

[bat-kam]

Or maybe valve clearance?

[Gassoon]

Could be valves, or even the tensioners? (At least the front one will be easiest to check!). Maybe the front one is stuck?  Might be nothing to do with the noises you hear, though, a lot of stroms make frightening noises but just keep going!

I would still test the simplest things first - Eg, another set of new plugs (or old ones you know are OK) with decent crush washers, and threaded in and torqued up carefully. Maybe even new plug caps on the front (plenty on ebay). Not sure about the coils on the DL, but in the past (on other bikes) I've simply swapped over the leads to coils to test them - so if one coil was dodgy, once 'swapped' over the other cylinder would start misbehaving, thus proving the coil was faulty!

I would even do the 'looking at the running engine in the dark' thing again, but get someone to help, maybe hold a mirror up to see under the tank a bit... maybe even lightly spray a bit water around the electrics to bring any issue out .

[bat-kam]

I found out Something interesting about spark on my dl today. I am not sure if this is the route cause of unsettled idle.
When I unplugged the lead of the side plug and started the engine there was clearly visible spark jump of the lead.



When I did the same with the front plug there was no spark jumps of the lead


It was the same story with the rear cylinder. Is this normal? Is the top plug used only at higher engine revs? I reved it 7k rpm and could see any sparks either front or rear cylinder.

Is this clear indication that both coils should be changed?