Hunting revs on start up from cold and power delivery.

[Stumpyone]

Hi guys,

Not sure if any of you have experienced this so thought I’d ask. On starting from cold, my SE hunts on the revs between 900 and 1500 revs for quite a while. I generally don’t let it sit to warm up but start and go within a couple of minutes but all the time in those couple of minutes, it continues to hunt on the revs. Over the past 2 weekends I’ve covered about 1800 miles on it and I have now noticed a definite notchyness in power delivery in that,  as I’m turning into a bend and start to feed the power in it comes in sharply and not feathered which on a couple of occasions on right handers in Wales this weekend caused the rear to twitch… a bit unsettling .

Have any of you experienced either issue on yours? Welcome any advice.

P.S. last serviced 8,000 miles ago

Cheers

Mark

[DaMonk45]

Just to say you have done it.
Have you run some fuel injector cleaner through it?

[Stumpyone]

no not yet but not a bad idea for starters

cheers

[azgman]

Definitely fuel related. Most likely cause would be the injectors. If the injector cleaner doesn't solve the problem, I would drain the tank through a filter to see if there is any crap in the tank. If there is, you may want to replace the fuel filter and possibly get the injectors removed for a thorough cleaning. Good luck!

[cropbiker]

Also... You could try running the ECU auto calibrate.

Start the engine and leave it to get to temperature and then leave it running for 12 minutes if I recall correctly

[Stumpyone]

Thanks cropbiker. I'll give that a go.

[Volfy]

Quite often it's because of some carbon build up on intake valves.  After the bike has cooled off and sat cold for a while, the carbon becomes desaturated with fuel and will act like a sponge soaking up the atomized fuel mixture on start up.  This causes the fuel mixture to go lean, which in turn causes the ECU to overcompensate.  The lean-rich-lean-rich yoyo'ing is what cause the RPM hunting.  After a while, the carbon deposits get saturated again, and the bike's fuel metering stabilizes again.

This happens most often in the spring time, because the engine has been run in cold winter months, where cold start fuel mixture can be very rich.  That exacerbate the carbon build-up.

I usually just treat the fuel with Techron (or your favorite carbon deposit cleaner) and the problem goes away.

[Coconut]

Manual procedure for carrying out "Engine adaption" :

• Ensure the engine is COLD
• WITHOUT TOUCHING THE THROTTLE, Start the engine
  and allow it to warm up until the Cooling Fan comes on.
• Leave the engine to idle for a further 12 minutes.

After doing this if your Cruise Control warning light is ON at Ignition On,
but cruise control will not engage, then see here :
False Warnings for further information and how to reset it.

Cheers