Bike startup problem. Advice needed.
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Road Warrior
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Bike startup problem. Advice needed.
Ok: here the problem.
I have a '07 FXDC.
When I start up the engine, from a cool engine condition (bike stopper at least 4 hours) it starts ok, within the 5-6 stroke of the engine in case of very cold weather, but for the subsequent 1-3 minutes the engine is very irregular, with the minimum revving up to about 900 rpm and then dropping very low, occasionally to almost a stop (sometimes even missing a beat).
This both in very cold and relatively warm weather (here in Italy it's now around 20 °Centigrade)
When the engine is warmed up somewhat (1-3 minutes, as I said), the irregular minimum disappears, and the engines runs as smooth as butter.
The bike has about 5000 km on it, Khrome Werks exhaust, active exhaust bypass (i.e.: the active exhaust valve is aways open) and, for the rest, is completely stock.
I took down the plugs at the end of a 3 miles run at normal state road speed (55 mph) and they are whitish (which would indicate a lean condition on an old bike but that the dealer told me is normal on my model which burns lean due to european environmental bull****).
I have this same behavior with different fuel brands from different stations and has been troubling me for a couple of months now.
I wander what could be the cause of this behavior.
Damaged oxygen sensor? Damaged Air pressure sensor? Damaged Air Temperature Indicator? Something else completely different?
I have a '07 FXDC.
When I start up the engine, from a cool engine condition (bike stopper at least 4 hours) it starts ok, within the 5-6 stroke of the engine in case of very cold weather, but for the subsequent 1-3 minutes the engine is very irregular, with the minimum revving up to about 900 rpm and then dropping very low, occasionally to almost a stop (sometimes even missing a beat).
This both in very cold and relatively warm weather (here in Italy it's now around 20 °Centigrade)
When the engine is warmed up somewhat (1-3 minutes, as I said), the irregular minimum disappears, and the engines runs as smooth as butter.
The bike has about 5000 km on it, Khrome Werks exhaust, active exhaust bypass (i.e.: the active exhaust valve is aways open) and, for the rest, is completely stock.
I took down the plugs at the end of a 3 miles run at normal state road speed (55 mph) and they are whitish (which would indicate a lean condition on an old bike but that the dealer told me is normal on my model which burns lean due to european environmental bull****).
I have this same behavior with different fuel brands from different stations and has been troubling me for a couple of months now.
I wander what could be the cause of this behavior.
Damaged oxygen sensor? Damaged Air pressure sensor? Damaged Air Temperature Indicator? Something else completely different?
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Road Warrior
Joined: Dec 2007
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No.
Not the throttle nor cables.
Bike is up, stationary, no stand.
Clutch pulled or released (in netural), no difference.
The minimum is irregular, but the irregularity in itself (up and down revs) is quite regular. It cycles down with revs, then sputter, then up again in about 10 seconds or something like it.
Since I have to go up three floors of the spiral ramp of a subterranean parking lot, such irregularities can become pretty... exciting. Especially if the engine loses a beat...
Not the throttle nor cables.
Bike is up, stationary, no stand.
Clutch pulled or released (in netural), no difference.
The minimum is irregular, but the irregularity in itself (up and down revs) is quite regular. It cycles down with revs, then sputter, then up again in about 10 seconds or something like it.
Since I have to go up three floors of the spiral ramp of a subterranean parking lot, such irregularities can become pretty... exciting. Especially if the engine loses a beat...
Last edited by 99octane; Apr 23, 2009 at 08:03 AM.
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Road Warrior
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I'll try starting the engine with the light still on and see if it gets better then. Thanks.
Supporter
Joined: Jan 2007
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From: along the shore of Mishigami
Look in the throttle body, there is a little orifice with a metering needle in it. Spray a little carb cleaner in the hole ,turn the ignition off/on a couple of times. This action moves the needle. The part we are dealing with is the Idle Air Control modulator. This controls the idle mix.
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Road Warrior
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Thread Starter
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Road Warrior
Joined: Dec 2007
Posts: 1,437
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From:
Look in the throttle body, there is a little orifice with a metering needle in it. Spray a little carb cleaner in the hole ,turn the ignition off/on a couple of times. This action moves the needle. The part we are dealing with is the Idle Air Control modulator. This controls the idle mix.
Hope this helps you find your problem!