Idle and feel

[cjwheeling]

I have a 2002 R1150RT that I just purchased a few weeks ago. I'm wondering about the idle feel and speed that it should have. The 18000 mile service was performed on time (as were all the other services) but I just wanted to make sure that everything works like it should. It seems to idle somewhat like a Harley, chug-chug-kchug-kchug-chug. Idle speed is approximately 1000RPM.

Thanks,

Michael

[Ken H.]

1000RPM may be a bit low. 1100RPM is more common. Some tweaking of the idle speed can be made with the LBS (large brass screws) on the throttle bodies, done at the same time as a TB sync. as they will effect the sync too.

[Stickerbush]

The irregular idle (sounds like it hiccups every few seconds) is normal for these bikes--mine has done this since new. I attribute it to the computer-controlled fuel injection (aka Motronic)constantly making adjustments to reduce emissions and fuel consumption.

[ShovelStrokeEd]

Actually, at idle, that's not true. The Motronic is operating open loop at that point and makes no corrections not dictated by the sensors.

 

Two things can influence this. Too lean a mixture causing the occasional misfire is the primary cause. One of the sensors can also be out of calibration by a bit which can cause the too lean condition. Not much to be done.

 

My GS Adventure is smooth as can be at idle, partly at least due to the twin spark design allowing better combustion. My 1100S is rough as a cob unless its really hot at which time the silly thing purrs like a kitten. I just live with it.

[Stickerbush]

Ah, the mysteries of the Motronic. I know the idle on my '00 R11R will smooth out when I pull the CCP. What exactly do you mean by "makes no corrections not dictated by the sensors"?

[ShovelStrokeEd]

I mean it is not operating closed loop and making continuous mixture corrections based on information from the O2 sensor. It is working from the idle base map and only takes into account engine speed and throttle position modified as below.

 

The sensors in play are the barometric pressure, oil and air temperature and throttle position as well as crank position for ignition timing purposes. In fact, I wouldn't wonder if the crank position isn't the primary cause of the stumble. It is very primative on the R and K bikes with only two pulses per rev. A missed firing event or even just a poor one could upset the pulse timing enough to whack out the ignition timing calculation. That could make for a rough idle indeed. Maybe they go open loop on that as well although I would doubt it.

[cjwheeling]

Oh yeah, I forgot the other part of the question. Is it possible that the octane is affecting the idle? The owner's manual stipulates 89 octane minimum, but the sticker on the gas cap states 91. Any recommendations? I've tried both, but it hasn't seemed to make a difference yet that I've noticed.

 

BTW, I've had over 20 (that's not a typo) bikes, this is my first fuel injected bike. Ironically, it is the worst 'carbureted' motorcycle I've owned. Between the constant surging at anything less than freeway speeds and the lumpy / missing idle, I'm less than convinced that fuel injection (at least on this bike) is the best choice. IMHO .

 

Thanks for all of your input, this site is a great resource.

[ShovelStrokeEd]

Not likely an octane problem.

 

Sounds to me that the bike needs some TLC. Valve adjustment, spark plug check at minimum, throttle body synch and maybe a good check for leaks around the throttle bodies. Do you know if the 6K service was performed?

 

I would seek the help of a knowledgable local rider and do this work yourself. You'll save big bucks over what the dealer charges and be able to take all the time needed to do the job right.

 

These things run pretty darn well when they are right and they are not all that tough to get and keep right. There are any number of "cures" for surging you can try or just don't ride where it surges.

[cjwheeling]

lol, don't ride where it surges. I'll be stuck in my garage

 

It's not that bad, I guess I'm just used to perfect throttle response that I get from carburators, I've seen some threads on spark plugs and such to try. BTW, all of the services were performed at the dealer where it was purchased on time.

[Pictou]

I would agree with Ed that something is not right with your bike. My twin spark 04RT purrs like a kitten at idle and has no hint of surging. I think its worth getting it checked out.

[Ken H.]

Hi ____________ (if you fill out your profile, we'll know your name!)

 

Sounds like the bike is due for an extensive, detailed tune up. If you want a detailed procedure to follow, PM me.

[Bill_Walker]

lol, don't ride where it surges. I'll be stuck in my garage

Since all your previous bikes have been carbureted, is it the case that your previous bikes have been cruisers, or other bikes with long-stroke engines? One standard piece of R-bike advice that hasn't been given here yet is that these bikes may like to be ridden at higher RPM than you're accustomed to. I typically keep mine above 4000 rpm except in first gear. It's smoother and surges less over 4K. Then again, my RT is an '04, with the surge-reducing dual-spark heads.