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By Artistav8r
#87120
My 2015 Classic EFI has a problem with damp winter mornings. Starts OK, I warm it up for 5 minutes or so, then set out. First few minutes, everything is ticking along normally, then about 5 minutes into the ride, it starts to cough, sputter, lose power and backfire. Sometimes stalls out completely. If I can keep it running, this all ends a couple of minutes later and it runs like a top for the rest of the day. Been doing this for two winters now. Never a problem in warm weather. Any ideas? Just had a service, new plug, HT lead fine, using Esso 97 Octane. Very puzzling.
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By Haggis
#87122
In my opinion, it's down to the transition period with oil temp sensor on the back of the cylinder head.
It tells the ecu if the engine is hot or cold. If cold then please supply a richer mixture.
As the engine warms up the sensor changes its output telling the ecu the richer mixture is not required now.
It's at this time that the cough and splitter will appear.
It's either keeping the mixture too rich for the warming up engine or leaning the mixture out before the engine is warm enough.
#87128
I would pull apart every electrical connector I can find one at a time and soak in wd40 or similar, then if this works or not pull them all apart again and apply silicone grease to them all also silicone grease the battery terminals and switches
To me it sounds like damp getting into the electrics
I may be wrong but doing the switches and connections is no bad thing to do
Hope this helps Dai
#87147
I'll think Haggish is right. Same problem with B5 2011 and the most simple way is to disconnect O2 sensor. Don't mind the warning light or you can disconnect it too. Other possibility is O2 sensor eliminator or extra resistor to oil temperature sensor with swich.
The same problem happens, when kick starting is easy when motor is cold but not easy when motor is warm. There is no air temperature sensor in the system and when starting the bike, ECU thinks the air temperature is the same as motor oil temperature.

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