Is there a "cold bug"

1364 Views 9 Replies 6 Participants Last post by Pete, Jan 12, 2015

Em4n

Discussion Starter · Jan 11, 2015

Alright, so earlier this week it was 19 degrees one morning when I had to go to work. The bike fired up just fine and I gave it a few minutes to warm up before I took off. Everything seemed to work fine until I hit a stoplight... The bike didn't want to idle and it actually died. The voltage was fluctuating and I could watch the headlight dim out as the idle dropped near 500 rpm. I restarted the bike and held the throttle just a hair and everything was fine. The next time I fired up the bike that day it was 27 degrees and everything was normal on it. I'm pretty sure that it was just so cold the engine couldn't stay at anywhere near operating temperature while moving, and that caused it to screw up the fuel/air mixture and kill the bike.

I have had no further issues with it since that though.

2006 flhtcui

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duecedog

· #2 · Jan 11, 2015

As I recall, at least on my bike, the stator doesn't put out enough voltage when the rpm goes below about 900. If it wasn't idling high enough it could cause the lights to flicker and pull a pretty good draw on the battery. When you restarted it and held the throttle open a little you raised the rpm to a level that allowed the stator to put out voltage, thus providing enough voltage for the battery, spark plugs, lighting, etc.

(this could also be caused by loose or dirty connections on the battery cables)

My concern would be what caused it to idle that low in the first place.

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Em4n

Discussion Starter · #3 · Jan 11, 2015

Well I felt the front cylinder, head, and exhaust. It wasn't even warm, but it sounded fine and felt fine as far the the engine running. They back cylinder was warm, but not hot...

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GotGold

· #4 · Jan 11, 2015

Might just be what the bike likes, warmer weather. My Sporty was "cold blooded" I'd have to run the enricher until it really warmed up good, if at all. My nephew has the same thing, carbed Sporty, died right at a light, that bike always runs like a top, it was just cold. My RK doesn't seem to care how cold, it fires and runs great all the time, but its EFI also.
Keep an eye on it though it might have some upcoming issues.

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Pete

· #5 · Jan 11, 2015

You know that guy who said that you don't need to let your bike, car, boat or airplane engine warm up before you takeoff - he wasn't me.

At low temperatures, it is best to let your motorcycle engine warm up until it is near a normal operating temperature before riding away. At 45 degrees that is probably around ten minutes, at 19 degree it might be 20 minutes. You don't have to wait until the engine oil is 220 degrees, but it should at least be in the 100+ degree range.

I ride all winter long, a lot of it in the North Carolina mountains. A fuel injected bike, mine is a 2009 Dyna SG, should run just fine even at very low temperatures. One the bike is started and running, it will eventually get to a normal operating temperature, no matter how cold it is outside. When really frigid, it can take a while to warm up though. That is why it is best to let the engine warm up, under no load, enough that the oil is actually circulating and lubricating the engine parts before you take off.

What I suspect happened to you was that you had a transient fuel issue. At 19 degrees, any water in the fuel system can cause the exact problem that you described. You can get icing in the intake and all sorts of other situations that you would never see at 70 degrees F.

I add both Marvel Mystery oil to the my gas and an agent that keep the alcohol in the gas from causing moisture problems. I change my plugs every winter and it is a good idea to check your plug wires too. Winter brings out the worst in motorcycles.

Pete

Em4n said:
Alright, so earlier this week it was 19 degrees one morning when I had to go to work. The bike fired up just fine and I gave it a few minutes to warm up before I took off. Everything seemed to work fine until I hit a stoplight... The bike didn't want to idle and it actually died. The voltage was fluctuating and I could watch the headlight dim out as the idle dropped near 500 rpm. I restarted the bike and held the throttle just a hair and everything was fine. The next time I fired up the bike that day it was 27 degrees and everything was normal on it. I'm pretty sure that it was just so cold the engine couldn't stay at anywhere near operating temperature while moving, and that caused it to screw up the fuel/air mixture and kill the bike.

I have had no further issues with it since that though.

2006 flhtcui

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Em4n

Discussion Starter · #6 · Jan 12, 2015

Thanks for the tips guys... Now to figure out how to explain to the neighbors why my bike is idling in the driveway at 5 a.m. for 20+ minutes

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peanut

· #7 · Jan 12, 2015

Em4n said:
Thanks for the tips guys... Now to figure out how to explain to the neighbors why my bike is idling in the driveway at 5 a.m. for 20+ minutes

Tell them it's because you are getting ready to protect their freedom. That should work.

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ciscokid

· #8 · Jan 12, 2015

my scoot is a cold blooded betoch. she will not idle when cold. i just let her get nice and toastie then she runs just fine an dandy.

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Em4n

Discussion Starter · #9 · Jan 12, 2015

peanut said:
Tell them it's because you are getting ready to protect their freedom. That should work.

I live on base... Everyone here does that, so that excuse doesn't work...

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Pete

· #10 · Jan 12, 2015

That can be the sticky part! <g> My Dyna is pretty quiet at idle but I don't think that the neighbors would appreciate it idling for 20 minutes at 5 am.

Pete

Em4n said:
Thanks for the tips guys... Now to figure out how to explain to the neighbors why my bike is idling in the driveway at 5 a.m. for 20+ minutes

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