Dropping mpg, hesitation at 4,000 rpm

[Pdiddy21154]

I have an 07 and love it. Recently I've noticed my mpg dropping. From 41 to 38. I know not a big deal but with that comes hesitation at 4,000 rpm. I just recently put new plugs from my dealer. Everything is tightened down. My 1st and pretty easy. Same deal. Let's back up a bit. This summer my battery would start to die and the bike would start to stumble and backfire. I had a new stator installed. What am I missing here? Ecu? All ears. I'd like to do this on my own if possible to save a trip, and cash, at the shop.

[Quiksilver]

How many miles? Have you cleaned the fuel filter or checked the fuel injector screens?

[RedBusarider]

What plugs did you go with? Iridium Plugs work great - for me.

Have you ever added Seafoam? or something like that?

I agree that you might need to remove the fuel pump and clean the screen etc.
Try the Seafoam first.

How old is the battery? Have you check the voltage and or had it load tested?

Where do you live. Hot or cold climate?
Any Mods?

[Samaki]

I did some research earlier when replacing the plugs on my 2011 and found posts that showed the iridium plugs delivered less mpg than conventional plugs. You might check and see what your dealer installed. If it was iridium then you at least have a probable answer.

[E Zurcher]

I did some research earlier when replacing the plugs on my 2011 and found posts that showed the iridium plugs delivered less mpg than conventional plugs. You might check and see what your dealer installed. If it was iridium then you at least have a probable answer.

That makes no sense at all. Does not pass the logic test.

[RedBusarider]

I did some research earlier when replacing the plugs on my 2011 and found posts that showed the iridium plugs delivered less mpg than conventional plugs. You might check and see what your dealer installed. If it was iridium then you at least have a probable answer.

Could that have been for Gen II's? ^^^

I put Iridium plugs in mine and have seen 50mpg on a cruise.
OP should have a Gen I.

I assume that the Iridium plugs come in different flavors and if the wrong set was put in, that might do it.

Haven't heard back from the OP to see if the problem started before or after the new plugs were installed.
I assume that he installed them, and checked the gap. So he should know what is installed.

I still think the fuel screen might be dirty. OP didn't state what his mileage is and if he ever has looked at the screen and pump.
Taking out the pump will also let you look in the tank and see if there is any sediment in there. Could have gotten some bad/dirty gas? ???

I would look over all the hoses too. If any are cracked or have a pin hole that could cause some problems.
There have been cases where a hose slipped off and reattaching it fixed the problems. Worth a look.

[Pdiddy21154]

Bike has 27,000 on it, power commander and after market pipe. New plugs are iridium but the hesitation at 4 grand was there before but not as noticeable. I bought the bike with 12,000 on it. Since I have owned it the air filter and gas filter have not been changed. That stuff is easy. How would get to the injector screens. I ride in Wisconsin and rode in temps like this upper 40's. Use Seafoam all the time because the crap they put in the gas here. Battery is new. Anything else? Thanks for all your input. This is a great guys.

[dadofthree]

I always noticed a slight drop in mileage right after changing the plugs in my Gen I. It might straighten out in 500 miles or so. Mine always did. Download the free service manual for your bike. The electrical chks are simple. From memory you should see 13.6 - 14.6 VDC across the battery at 5K RPMs. Chk out the manual.

[E Zurcher]

27000 and you have not changed the air filter? I would start there. If you have crappy gas the fuel filter would be my next step. The 07s have an internal fuel pump filter arrangement and the filter is expensive. There is a mod on this forum to bypass the stock filter and go external, otherwise it's like 250 bucks for the stocker. To clean the injector screens you have to remove the fuel rail and pull the injectors. Its easy but make sure you use the correct size screwdriver on the mounting screws because they are very soft and can be frozen in place. You will also want to replace the o-rings on the injectors. You can send them out for cleaning at like 25 bucks each and that is the best way to go if you have the cash.

Two years ago I got some bad gas that clogged up my fuel system and that was the path I had to take to get it right.

[phatj33pyj]

Slipped from 41? I don't think I've ever gotten more than 36. I must be the worst driver on the forum.

[Pdiddy21154]

Thanks guys. I'll hunt down the forum on the fuel filter.