Engine Oddities

[NAKID]

2006 S2R1000 with about 30800 miles.

Daily rider, gearing has 80MPH at right at 5000rpm in 6th. Today on the way to work, 6th had 5000rpm at about 72-73MPH. This happened about halfway through my ride. Not that it suddenly jumped, but slowing down and speeding back up about halfway to work I noticed the change. Almost seemed like I was missing 6th, even though I was in it already. Got to work and the bike is idling at around 2000rpm.

Any ideas?

[Dirty Duc]

At idle, does it sound like it is idling at 2000?  The tach may be indicating the wrong RPM if nothing else changed.

The only other ways that I can think of for RPM-speed to change mid-ride is clutch slip or speedo error.  add that to the change in indicated idle speed...

[NAKID]

It definitely sounds like it's idling high and sounded appropriately high at 80MPH as well...

[Speeddog]

After key on, and gauges sweep, does tach return to zero?

[NAKID]

Yes.

[Speeddog]

Sounds like an intake air leak.

Your motor has the ECU controlled idle air valve, it may have given up, or gotten stuck full open or the like.

Or one of it's hoses has come off/failed.

Or a leak elsewhere.

[NAKID]

Sounds like an intake air leak.

Your motor has the ECU controlled idle air valve, it may have given up, or gotten stuck full open or the like.

Or one of it's hoses has come off/failed.

Or a leak elsewhere.

I understand how that could affect the idle, but woulf that affect RPM at speed?

[hackers2r]

I don't think the high idle would affect the speed differential.  Maybe clutch slipping or VERY low tire pressure; but I'm sure you would have noticed that.  What about other gears?  Were you having to constantly ride at higher RPM?

[NAKID]

Other gears seem proportionately high, as if I was completely missing a gear, even though I shifted through all six...

Oh, and tire pressure is checked daily and is around 32-33 front and 33-34 rear.

[Speeddog]

I understand how that could affect the idle, but woulf that affect RPM at speed?

Wouldn't effect rpm at speed.

Check the clutch, with bike rolling under moderate throttle, ideally going up a hill, fan the clutch quickly and see if it brings the rpm back down solidly when the clutch engages.

[NAKID]

Wouldn't effect rpm at speed.

Check the clutch, with bike rolling under moderate throttle, ideally going up a hill, fan the clutch quickly and see if it brings the rpm back down solidly when the clutch engages.

I'll check that when I head home.

just went out to the bike and started it up. Idling right about 1100-1200rpm now even after about 5 mins. Didn't find any air leaks, cracked hoses, etc. We'll see how it performs on the way home.

BTW, (Nick you already know this) but this is a stock, original clutch fully open, if that makes a difference.

[rule62]

I wouldn't be surprised if it were just a glitch with your gauges. (The high idle may have been more of a perception because of what the tach was indicating rather than what was actually going on). I had something similar happen with mine. Turned the bike off, turned the key and let the gauges sweep, started the bike, no more problem.

I was able to re-create the problem once when I hit the start button before letting the gauges make their full sweep.

Hopefully it's nothing. Good luck.

[NAKID]

I wouldn't be surprised if it were just a glitch with your gauges. (The high idle may have been more of a perception because of what the tach was indicating rather than what was actually going on). I had something similar happen with mine. Turned the bike off, turned the key and let the gauges sweep, started the bike, no more problem.

I was able to re-create the problem once when I hit the start button before letting the gauges make their full sweep.

Hopefully it's nothing. Good luck.

Thanks Ryan. I did just that when I got to work. Shut the bike off. Turned the key to the on position and let the guages sweep. Restarted the bike. High (~2k) idle.

But, like I said, bike is idling normally now.

We'll see on the ride home...

[NAKID]

Rode home and back to work today with none of the problems I encountered yesterday....

[hackers2r]

Possible explanation of the lower speed at same RPM, maybe the clutch lever needs adjusting as the plunger is too far out allowing slight clutch slippage?  But this doesn't address the high idle.  Just a thought.