The ECM program uses a warmup table that adds fuel in incremental stages as the engine warms. I can't say for sure but I believe that when it is real cold out that the motor may be slow to come up to full temp, this keeps it in a richer running condition.

I don't know what the stock ECM settings are so I can't say how much it affects stock bikes, but with SERT loaded bikes it is visible and appears to be very rich. I have reduced the warmup enrichment on my SERT tune across the board, I did this because it seemed to run very rich during warmup.

I still get easy starting and smooth running without running as rich, and I have ridden many times in the low 30's anda fewtimes in the 20's. I made some other adjustments at the same time so can't say that this was the only reason, but my mileage went UP.

I'm only throwing this out there because it could explain some of what you might be experiencing.

This is also one of the neat things about playing witht he SERT, you can sure learn more about the hidden things that make your bike go.

 

Well damned if I'm not a dingus, I've got a SERT on the bike! Never thought to play around with it. Thanks Hobe.

<><Peace

 

I cannot believe no one has mentioned the biggest factor in loosing gs mileage i the winter. WINTER GRADE gas. they add additives to keep the fuel from freezing or gelling in certain parts of the country. The additives do not burn as well and gives worse gas mileage.

 

Now that I did not know. Thanks man.

<><Peace

 

hmmm... I ALWAYS have a FULL tank when its freezing out !

 

I think your correct, IF the fuel suppliers gave us summer gas. I know up here in Washington they've gone to the "winter" gas and mileage goes down in everything, truck, car and Sporty. [:'(]

 

I know that they change the formula on diesel as it will gell in cold weather, you get a winter formula in many regions. I don't think that gelling is a problem with gas, I don't think that freezing is an issue in most climates, and have never really noticed a difference in mileage from summer to winter.

I drive a diesel truck and we also have several gassers, the truck is the only one I have ever noticed a change. If there is a difference in gas blends, and I'm skeptical, I don't think it makes much difference or it isn't inmy part of the country.

All of that said Idon't thinkthat it would make the difference in mileage that several folks have mentioned in this thread.

 

yep...you lose prob at LEAST 5% for that alone....I think its some EPA crap as opposed to some anti-freeze concern..it far outweights any benefit from colder/denser air...