Rough ish idle

[Guest alexanderfitu]

Hi all

 

Did a long ride through central london today, so got the engine nice and hot.

 

I have noticed that between 1000-2000rpm I have a bit of a hesistation. Under very very light throttle loads the revs yo-yo up and down, obviously causing a slight speedup/slow down motion.

 

I have also noticed the revs do this when cold starting. No real misfires, just the up-down motion.

 

Is it just mine (boo) or just what they are like (can live with it if thats the case)

[Guest Stavig]

Are you starting the bike and go immediately? If that's the case then it's absolutely normal. And the colder it gets the more it will take to calm down.

The engine needs to warm a bit so rev take some time to settle.

[Guest dukie]

its normal its happens to me every morning but when it warms up its gets better, but when it is really cold it takes longer, it must be how the bike is it doesn't do it on my other bike, I wonder if there is a way of making it better without waiting 15-20min for it to warm up 

[embee 7,288]

There tends to be a slight hunting while the feedback gets established, but this should only take a minute or so after a cold start. Idle speed probably won't settle at its final value until the coolant is up to a reasonable temp (maybe 50-60C at a guess), that's the way it'll be programmed.

 

A couple of easy things I'd suggest. 

 

Check the plug caps are fully seated, I found one of mine wasn't properly down and had noticed a slight roughness. Doesn't cost anything.

 

Second try the supposed ECU reset (still haven't heard if it's official, but can't do any harm anyway).

Disconnect battery for a few minutes, time is uncertain but 30mins should be more than enough if it works. Reconnect.

Start from cold and DO NOT TOUCH THE THROTTLE.

Leave it idling to warm up until the fan cuts in, normally something like 15mins.

Stop engine using kill switch.

Turn off ignition.

 

That's it apparently. I've done it once, not sure what effect if any it had, depends whether it needed any reset I guess. It's free so worth a try.