The colder it gets, the more MPG will drop. just will.

 

QuaDancer, have you thought about a #46 pilot jet, if the mileage goes up then go back to the stock 45 pilot, if performance goes down go back to the 46. I've got the stock jets in my carb, raised the needle two washers and have the a/f mix out 23/4 -3 turns. About 42-44 intown and 48 on the road.

 

I get about a 10% drop in mileage with winter temps and ethanol added to the gas.

 

The cool weather and the wind have dropped the mileage on my 08 heritage about 5-6 mpg.

 

I agree with the cold temp+10% ethanol. I've dropped 5-7 mpg this winter. I'm gettin about 35 now, and got 40-42 all last summer.

 

I was out of the USA and not driving vehicles for a while. I came back and found the ethanol fuel gets poor MPG.

I would hope that 93 oct is 93. Wind has been rather strong in my area too.

Have you;
Changed oil type.
Check tire pressure.
Checked spark plugs.
Still feel you ride the same.

 

10% ethanol might drop MPG by about 0.5 % to 1.0 % maxium. To drop MPG by 10% would mean that the BTU content of ethanol was zero . . . and that's not happinin'. More likely that cold weather means a greater amount of cold start enrichment and for a longer period of time. But most of all I'd be willing to bet that when the weather is warmer we all ride just a bit more, idle the engine a bit less and ride a bit further each time we ride . . . put all that together and it'll cause a huge change in MPG along the lines that some in this thread mention.

 

Pilot doesn't make much difference in road speed, since it only applies to idle and just off-idle throttles. I had the 45 in there and it popped back, spit and quit at idle (former owner never touched carb but added pipes). The 48 wasn't quite rich enough either, so I put a sewing machine needle in my vise and forced the jet down on it thru the tower holes, peening them out about .02", which made it just rich enough to run, and even better now that it's warm out here. Harley mechanic said he'd never seen anyone use a #50 jet except for racing, and I can't find any intake leaks. I'll be replacing the gasket anyway, just in case. Only thing left is defective carb or bad main jet, IMO.

Trick for the enrichener I use is to pull it out ONLY for idle, and shove it in once leaving a stoplight, until I don't need it anymore. Forgot it was out once and my mileage definitely tanked.
EDIT: Woopah!!! Just gassed up from our last run where I was solo and hit 41.7 mpg! Best ever yet, and I'm satisfied nothing is really wrong if I get that again. I think the ol' lady needs to get back on the diet again.

 

mine dropped 10% and all i can find so far is it is the fuel causing it. i get same mpg in summer or winter maybe because thundermax retunes for conditions. I even went so far as to change to the stock ecm and same 10% drop there. if i ad fuel additive i gain back the 10% loss. i guess epa thinks you can pollute less with cleaner burning fuel but use more of it.

 

Road trip last year, two weeks through the midwest, late June to early July. 40-45 MPH on a 2008 Heritage loaded down...except in Kansas. Dropped to 28-33 MPG after my first fill up in Goodland, KS. Crappy mileage all the way across Kansas, so much so that after leaving Wichita and dropping to 28 MPG in to Oklahoma, I called the HD dealership in OKC to bring my bike in. Told them what was happening with fuel mileage and they said bring it in. Filled up in OK at the same time I called the dealership. When I rolled in, I was back to 40-42 MPG. Service manager asked if I had come through KS because they'd been getting a lot of bikes coming out of Knsas having the same drop. Their belief is a lot of stations in KS are using higher levels of ethenol than reported. They said there was no point in them looking at the bike because the mileage was back up, indicating gas issues. Averaged 40-45 MPG the rest of the trip.

Getting ready to hit the road again in two weeks, including Kansas. We'll see if we have the same issue. Taking a few bottles of additive in case it happens again.