I have noticed that as the weather has started to cool off my MPG has decreased significantly. About 15% from 36ish to 31. In conversation with a co-worker we were discussing the effects on the fuel air ratio change due to the tempature change. Is the bike running richer from the air density change or leaner? Does the early Meg Marelly (I don't care that my spelling is wrong!!) compensate for air density change? The reason I am asking this here instead of on the fuel post is because there seems to be a more informed group on the touring page! Thanks in advance and if you are a post ***** that is going to reply that you don't know but it is a good question please save it for Annibuss's post!!

 

Cold air is denser than hot air. You will get more air to fuel. with that in mind, you mileage should be better on a cooler day than a hot day. I have not noticed any changes in my mileage. I'm running a 103 stroker.

 

Unless you're spanking it pretty hard or have some major high-perf mods, even at 36 you're running a little low. I can get in the high 40's if I drive 55 (but I never do) and I have the 95 kit w/cams, breather, pipes, etc...

And that's right. Cold air is denser so you'd get leaner. Which is sort of ideal since the engine will run a little hotter when the weather's cold.

 

What are you riding? Actually I probably have been lugging the motor some with the 6 speed seeing if my rev tech tranny has any of the mystery noises that the HD tranny has. Would the lugging induce the fuel consumption?

 

Ethanol blends get worse mileage than gasoline. Is your fuel a blend?

Suppliers add more methanol in the winter.

 

Nope just good old dino 91 octane.

 

I notice the same effect up here. For me I have a 10 mile ride to work in the morning and the same in the evening. My thought is the engine management is keeping the enrichment cycle on longer or never coming off during my relatively short ride. I am down in the lower 30's mpg when the temp gets below mid 30's F. Lat week when it was in the 20's in the morning I don't think the motor really warmed up!!! Niether did I!!!

Tom

 

There's an air temp sensor in the EFI system that helps govern the amount of fuel the engine receives. Maybe due to colder temps the mag-marelli is just sending more fuel. Combined with the cold idle circuit staying active longer when you start up, that might account for the lower mileage. BTW, 36 mpg seems low to me, too. I've got a 2000 RK with 95" build that gets low 40s riding around town, close to 50 cruising at 65.

 

Lugging ain't good. 2500 - 3000 range is best.

 

you're not riding far enough. takes a good 30 miles to bring to operating temp.