Author Topic: Idle speed dropped after 300 mile ride  (Read 482 times)

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Offline Kreton'sLC

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Idle speed dropped after 300 mile ride
« on: February 18, 2019, 02:36:00 am »
So yesterday when I pulled into the garage after a 300 mile ride, my idle speed dropped to around 900 RPM or so.  Nothing unusual about the ride itself - made 5-6 stops along the way and the ambient temp was between 39 and 65F, so heat shouldn't have been a factor.  When I started it up today it idled for a few seconds at 1200-1300, then dropped down to 900 or so again.  My previous bike exhibited similar behavior if the fuel injectors were a bit clogged, but typically shutting it off and restarting would deliver a normal idle.  But with the Connie restarting didn't improve the idle.

Riding the bike today did seem to bring up the idle a bit at stops to maybe 1000.  So when I got home I decided to fiddle with the idle adjustment screw . . . which wasn't where it was supposed to be according to the pic in the service manual.  Apparently at some point when the previous owner had it, some bonehead had wedged it up between stuff behind the fairing a good 6" above where it's supposed to be.  But after removing the lower-left fairing and positioning it where it should be, I adjusted it to where it was which is in the 1150-1200 range when warmed up.

Just wondering what might have caused the idle drop in the first place?  I added some Seafoam in case the injectors are clogged, and didn't see an improvement after my 60 mile ride today, but maybe that's not enough miles.  The bike accelerated and ran fine with the low idle, although it was a bit jerky shifting at lower rpm and I also noticed a bit more popping than usual during deceleration (I've got a Muzzy's slip-on and I understand decel popping is common with slip-on exhaust), but I figure these things could be due to fuel deprivation because of the low idle.

So was this just a fluke, or perhaps symptomatic of another issue?  The service records I've obtained suggest the air filter and spark plugs were changed recently enough where they shouldn't cause the problem.  And with just 22k miles, I wouldn't think the fuel filter would be the problem either.

Offline C. Moore

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Re: Idle speed dropped after 300 mile ride
« Reply #1 on: February 18, 2019, 10:41:12 am »
The idle on my '10 dropped a bit on a trip to Colorado in the late summer last year. I messed with the adjuster to get it back to 1100 or so. The next day the idle was too fast so I adjusted it back down. It stayed steady after that. I chalked it up to all the whiz bang electronics on this bike and called it a day. So yeah, probably just a fluke thing.
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Offline MAN OF BLUES

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Re: Idle speed dropped after 300 mile ride
« Reply #2 on: February 18, 2019, 10:08:21 pm »
multiple thing can and do cause these symptoms... "whiz Bang electronics" are often the problem with this particular model...

When thing are running fine one day, then without notice they "change", it indicates it wasn't a "slow creeping hidden thing"....

Most likely causes I've seen for this is (and it' usually around the 15k-20k mark..coincidentally) :

Poor electrical connection at the battery, and ground points on the frame.
     remove and scrub abrasively, all cable connectors, and connection points
Air filter may be at max service interval, and showing clogging...
     remove/inspect/replace if needed
Poor fuel/old fuel
    if still running on old fuel, get some new... but this bikes injector system really           show massive changes like a carb'd bike will.

Any changes "you" specifically made...(you mentioned the muffler), and or changes in oil.

I think the only time I had to "adjust up" that throttle stop, other than around 15k when the engine was fully broken in, was after I did a valve adjust/airfilter/TB synch and at that time I actually had to turn it back down... strangely to where it was originally...

30 YEARS OF KAW.....Rich R. (the other one..)  COG 5977  JUSTAMEMBAHNOW
and if you are gonna call me names... it's MR. Analdweeb if you please...

Offline Kreton'sLC

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Re: Idle speed dropped after 300 mile ride
« Reply #3 on: February 19, 2019, 08:28:10 pm »
multiple thing can and do cause these symptoms... "whiz Bang electronics" are often the problem with this particular model...

When thing are running fine one day, then without notice they "change", it indicates it wasn't a "slow creeping hidden thing"....

Most likely causes I've seen for this is (and it' usually around the 15k-20k mark..coincidentally) :

Poor electrical connection at the battery, and ground points on the frame.
     remove and scrub abrasively, all cable connectors, and connection points
Air filter may be at max service interval, and showing clogging...
     remove/inspect/replace if needed
Poor fuel/old fuel
    if still running on old fuel, get some new... but this bikes injector system really           show massive changes like a carb'd bike will.

Any changes "you" specifically made...(you mentioned the muffler), and or changes in oil.

I think the only time I had to "adjust up" that throttle stop, other than around 15k when the engine was fully broken in, was after I did a valve adjust/airfilter/TB synch and at that time I actually had to turn it back down... strangely to where it was originally...

Thanks MOB.  Could be the air filter or battery connections you mentioned.  Bad gas came to mind, although I refueled on the ride home with a top-tier brand (Valero) I frequently use.  The muffler was installed by the PO, so don't think that's it.

I'm also wondering if given how the adjuster was jammed up between stuff if a bump or vibration caused it since the adjuster requires very little force to turn.

Offline Bud

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Re: Idle speed dropped after 300 mile ride
« Reply #4 on: February 19, 2019, 09:24:09 pm »
If you watch the C14 forum over the course of a year or two, you'll find that there are all kinds of gremlins that people bring to the forum.  More times than not, the solution has been the one you were just given by MOB.  As I've heard him say a lot, abrasively scrub the ground connection on the bike and the cable end.  If it's not a sticky for the first thing to do when gremlins show their ugly heads, it should be.  Do not pass go, don't collect the $250 until you try that.  Taking it apart and saying it looks good doesn't count.  Hoping this simple fix is all it takes. :)
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Offline Kreton'sLC

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Re: Idle speed dropped after 300 mile ride
« Reply #5 on: February 20, 2019, 04:35:15 pm »
If you watch the C14 forum over the course of a year or two, you'll find that there are all kinds of gremlins that people bring to the forum.  More times than not, the solution has been the one you were just given by MOB.  As I've heard him say a lot, abrasively scrub the ground connection on the bike and the cable end.  If it's not a sticky for the first thing to do when gremlins show their ugly heads, it should be.  Do not pass go, don't collect the $250 until you try that.  Taking it apart and saying it looks good doesn't count.  Hoping this simple fix is all it takes. :)

Will do!