My bike will not idle steady, if I drop the idle adjuster the revs "purr" like a cat breathing, and the revs do not drop to below 1.9 or stay put. The bikes revs up to 2000 or 3000 revs and drops again repeatedly. If I turn the idle adjuster up the revs seem to smooth out at around 5000 or 6000 revs, but that is too high of course.

Any ideas as to what might be causing that? It is riding fine otherwise.

Cheers.

 

what is the history on this bike?...does it sit for long periods of time?....i would remove the carb and check all jets...check float also..and, than remove the fuel line to carb and put to on position in to a container to check to make sure fuel streams out smoothly...

i had similar issues after the bike sat for 4 months or so....after i cleaned the carb and valve adjustment (one was off), it starts and idles perfectly again...

 

Year and model of the bike would help. It sounds like you are only adjusting the idle speed. If you have a carb, the idle mixture also needs to be adjusted. And, as previously mentioned, the pilot jet could be restricted, a common problem.

Ride on
Brewster

 

Thanks. The Bike is a 2009 KLX250S9 - fuel injection (UK model). It had laid up for a couple of months. After faffing around with the Idle adjuster it seemed to clear up after another ride of 20 odd miles or so; but came back again.

After a few more rides and some fresh fuel (not just a top-up) it seems to have cleared itself. Seems I got lucky, otherwise I'd have followed your suggestions.

Hopefully problem gone away.

 

Hi, the idle problem seems to be related to when the bike is wet. The symptoms were absent during a recent dry spell, only to come back, and worse, when bike in rain all day while at work .

So when the bike is wet, the idle is not steady, when very wet the bikes revs up and down between 2500 and 3500 revs over and over, like a cat breathing.

I was at the traffic lights and a sports bike rider drew along side, my bike revved a couple of times at him , so I got a pitying "look" before he disappeared.

Any ideas of how cure this?

I'm thinking it could be a new air filter required, 8000 mostly road miles on the bike and still the original one. (Not much dust around in Northern Ireland.)

 

When my bike is wet in the rain and theres lots of humidity it runs ? and the idle bogs down then picks back up. If you are surging then I think your idle might be lean in the rain?

 

Washing and re-oiling your air filter is a good way to keep water from entering the intake, but it sounds like you have an electrical problem.
If it were me, first I'd run some injector cleaner through it. Then I would disconnect and grease(dielectric) all harness plugs related to the EFI. Could be simple as a loose connection somewhere.
Water can do strange things to a not so perfect connection.
I know when I ride in salty slush, my neutral light will come on faintly in any gear.

 

I would suspect that the TPS(throttle position sensor) is sending erratic readings to the ECM when it gets wet. The ECM looks at the TPS to determine if you are actually closing the throttle and most FI strategies open the idle control device(throttle stepper or air bypass) when you open the throttle. Problems arise when the ECM looses accurate TPS signal and doesn't realize that it is supposed to control idle speed because it doesn't know that the throttle is closed. Check the connections and you may need to backprobe the TPS signal wire at the ECM so that you can get an idea of what the voltage actually is.

 

What should the bike idle at?... I'm having issues after just adding a jet kit and Q4.

 

Spec is 1300 rpm but I bump mine up to about 1600.