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Help diagnose plz :(

Old 01-23-2010, 02:43 PM
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Join Date: Oct 2008
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Default Help diagnose plz :(

'06 f4i
bike sat for a couple months (don't think this is related)
ran fine when I took it out to fire it up & cruise the neighborhood (couple times)

just started an overhaul to get the bike back on the road (rear tire adjustment, rear brakes, frame sliders, clean/lube chain, change oil/filter, etc).

The problem: Bike starts fine, warms up fine (good idle speed) but then plumits after warmup. I can keep the bike alive with throttle but it dies @ idle.

When this first happened at initial startup, when I cranked it, it went into 3krpm, which made me nervous, so I started screwing with the idle adjuster (which I've determined is sort of useless) to compensate, couldn't get any adjustment from it, and it just died out.. after this I REALLY screwed with the idle adjuster, and at this point, I don't know where it is in terms of adjustment...

Question: If the idle adjuster were ALL the way out (increased/turned ccw), wouldn't it scream RPMs? and I assume all the way in (decreased) is when it "gets tight" and out is when it gets loose??

my thought was to get that right before further diagnosing but I can't tell how to determine proper set point. and like I said, I believe it's some other problem causing this anyway...

I have a dynojet/TB slipon. dj hasn't been modified, tried unplugging to see how it would run, no joy.

I believe the gas is ok, as I remember running it out and adding new not too long ago.

oil level @ balance point is ok
battery is ok...
I've never cleaned the K&N air filter, would that kill it @ idle and not affect during start/warmup??

hoping to get it fixed without spending a kidney @ honda.

any ideas what to check next???

I was all excited to be riding again and of course it's always something!

will check back soon w/fingers crossed. tyia

Last edited by abeham; 01-23-2010 at 03:27 PM.
Old 01-23-2010, 08:20 PM
backroad's Avatar
Join Date: Mar 2006
Posts: 69

3000+ rpm when cold, especially in cold weather is normal. The idle will gradually slow down as the engine warms up. I'd say you just turned the idle adjuster out when you didn't need to. Clockwise speeds it up, counterclockwise slows it down. Turn the idle adjuster back in (clockwise) until the bike idles at 1250-1350 rpm when it's completely warmed up and it will be fine.
Old 01-23-2010, 08:29 PM
Junior Member
Join Date: Jan 2010
Posts: 7

check your spark plugs to insure the proper a/f ratio. on my f3, the k&n sometimes needs to be cleaned and re oiled. hope this helps. O and by the way my bike will red line when i turn my idle screw all the way up.
Old 01-23-2010, 08:54 PM
datru's Avatar
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Join Date: Jul 2008
Location: Bellflower, SoCal
Posts: 109

Hmm, I had a very similar problem just a few weeks ago. In the process of my maintenance I removed the PC3/full exhaust I had and went back to stock. I also thought the 3K cold start was kind of weird too, since before it was around 2.5k or less. The other difference with me was I changed oil visc. from 10w-40 to 5w-40. Though I doubt the oil is the culprit. I too am curious as to how this turns out for you. Is it possible that your throttle or throttle cable is stuck somewhere and you adjusted the idle too low?
Old 01-24-2010, 01:43 AM
jonld's Avatar
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Join Date: Mar 2005
Posts: 647

start the bike and warm it up to operating temperature. never make adjustments to the idle adjustment when not at operating temp. until its warmed up and the cold start valve has closed your just messing the system up. Once its warm and dying out, hold the throttle steady to keep it running and then turn the idle screw in till it starts to race. then back it out till you reach your desired idle speed.
Old 01-24-2010, 02:42 PM
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Join Date: Oct 2008
Posts: 5

Really appreciate the input on this one. You guys are a solid group, here..

Turned out to be the idle speed. I just couldn't believe how much turning I had to do to get it right... brought back some fond ol memories of manually bleeding the brakes!

She's runnin good now. Thanks again

Til next time,
cyall later & ride safe.
Old 01-24-2010, 03:46 PM
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Senior Member & tensioner mod inventor ROTM WINNER FEB 2013
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Location: Kent, UK
Posts: 1,298

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