Significant drop in gas mileage

[Goodman4]

I've had my 07 for 8 months and have put over 6K miles on it, which is almost double what was on it when I got it. It runs great and I have no complaints except for a nagging feeling that there is a problem that caused the mileage to suddenly drop back in August after I put a new back tire on. I usually get gas at the same place here locally, but of course I get a gas a lot of places on the long trips. I check the mileage by doing the math on the fillups instead of trusting the dash mpg.

I got within 2 mpg of 48 for the first 3 months consistently. I got back from a 1000 mile trip and had the local Yamaha / Victory dealer put a new back tire on. The front was already replaced when I bought it. The back was the original tire. Right after that I took another trip and noticed I was getting 38 to 40. I had them look at it and they said they didn't see any rubbing or anything that would cause the drop. They thought maybe spark plugs, but recommended waiting until the next service.

I've continued to get 38 to 40 ever since. I sometimes feel like I might have lost a little power, but it could be psychological. And it would be so hard to tell with me almost never giving her all she's got.

I'm getting ready to take her to the dealer for the service. Any advice on what I should ask them to do / look for? It just is odd that it coincided with the tire change so closely. I've read other posts on this issue and sometimes they suggest the air sensor or a throttle body synch. I don't know if my dealer can do a TBS. They are really nice guys that seem to be pretty sharp, and I trust them, but I think they don't see a lot of feejers.

Thanks,

Paul

 

[SkooterG]

Most likely, there is no problem with your FJR and it's just normal variance. You are riding differently perhaps? Also, I always get worse fuel mileage in the winter. I go from typically mid to high 40s, to low 40s, sometimes 39. There are all kinds of factors that can affect your fuel mileage. Your riding habits (twist of the wrist) and speed are the biggest ones. But I definitely notice cold weather reduces the mpgs.

If I were you I would try this: Put the FJR on the centerstand and spin the rear wheel. With a hard spin it should go several revolutions before stopping. Then have someone push the rear down raising the front. Do the same to the front wheel. It should have the same result. If so, you are good to go there.

It could be a lot of things, but FJRs are pretty reliable. No doubt some will tell you to change plugs but in my experience they really don't go bad. I've got over 350,000 miles on FJRs. In the beginning I changed plugs at the 8k mile recommended interval, but now I change them only when performing a valve check every 30,000 miles. I notice no degradation in performance or fuel economy. I also rarely perform a Throttle Body Sync. I don't care what some people claim, it just doesn't really do all that much other than smooth out your idle.

Have you checked your tire pressures recently?

You could have a bad sensor, but that would be very rare. Tough to find too.

Did you have your wiring harness (ground spider) recall performed?

With only 9k miles or so, there really shouldn't be much going wrong with your FJR.

 

[SacramentoMike]

I'm usually right around 40, myself. I know a lot of guys claim a lot more, but they must ride differently than I do.

I did have a sharp increase in mileage once. Really dramatic. Then it went way back down again just as suddenly. That's when I found out about switching the speedo from miles to kilometers. And how to avoid it, of course.

 

[bluesdog]

I doubt if the spark plugs have much to do with a drop in fuel efficiency, unless there are other symptoms, such as hard starting, missing and stumbling etc.

A few things I'd look at:

Is the air filter OK?

Have you noticed any handling problems? Are front and rear brakes working well & not binding or dragging?

Have you serviced the brakes and clutch hydraulics?

How long since the final drive oil was changed?

The fjr is pretty easy to do your own wrenching on, especially with the help from this forum, so if you're at all concerned about the local dealership's service expertise, perhaps you may wish to do at least some of your own work

You might consider purchasing a sync tool, and doing the TBS yourself. Do the unauthorized one while you're at it, but a TBS probably isn't going to do much w/respect to fuel efficiency.

 

[Goodman4]

Thanks for the quick replies.

As long as it isn't a symptom of a bigger problem, I guess I don't need to worry a lot about it.

I am pretty sure my riding habits didn't change that much after the tire change in August. And with the change occurring in August when we had some hot weeks after that, I don't think I can factor in the weather that much. But I agree these are significant factors and I appreciate the ideas.

No handling problems. Final drive was a little low when I checked it AFTER I noticed the change in mpg, so they filled it up, but didn't change it. I had them check the brakes because I had a LOT of grey residue on the back wheel when I got back from the first trip after the tire change. They said it was just brake wear and my brakes still were in very good shape. But that bothered me a little. It was a trip through the mountains including the Dragon, The Gauntlet in GA, and the Cherohala, so I did ride it pretty hard that trip. I wouldn't have thought I used the back brake that much.

I will do the tire spin test tomorrow. That's a good easy check.

Skooter, how do I know for sure if the ground spider recall has been done? I asked the dealer if all the safety recalls had been done and they said they had, but I didn't ask about that one in particular and was wondering about it a little after hearing about the issues.

 

[mcatrophy]

...I had them check the brakes because I had a LOT of grey residue on the back wheel when I got back from the first trip after the tire change. They said it was just brake wear and my brakes still were in very good shape. But that bothered me a little. It was a trip through the mountains including the Dragon, The Gauntlet in GA, and the Cherohala, so I did ride it pretty hard that trip. I wouldn't have thought I used the back brake that much.

I will do the tire spin test tomorrow. That's a good easy check.

...

Check the rear brake pedal is not stiff, that would account for brake dust and low mpg, but may not show up in a casual check.

[edit] But you'd expect another symptom, the ABS light flashing, see here, so maybe not. [/edit]

 

[Redfish Hunter]

I hate to repeat what has already been said, but is your brake pedal sticking? The pedal can get a little sticky and hang up leaving a very slight application of your rear brake. I had this happen on Dad's '07, it is not unheard of on the FJRs. That would also account for some of your excess brake dust on the rear.

 

[Burnspot]

+1 on the rear brake pedal. On my '07, the pedal shaft had quite a bit of corrosion on it and it had reached a point where it was sticking ever so slightly. Cleaned it up and lubed it....and noted for more regular checks.

Call up Yamaha and give them your VIN; they can tell you what recalls have and haven't been done (if any).

 

[petey]

I see you had your milage drop during warm weather but, the position of the wind screen (higher position when it's colder) will make a difference in gas milage.

 

[odot]

El nino. Nothing you can do aboot it. Ride on, brother, ride on.

 

[Intech]

All good advice on things to check, but really you are in the normal range for most riders. You might also try running a can of Sea Foam through a tank.

 

[wheatonFJR]

All good advice on things to check, but really you are in the normal range for most riders. You might also try running a can of Sea Foam through a tank.

It may be in the normal range...but going from 48 to 38 indicates some significant change to me...

In my case, in 2008 in Colorado I went from 50 to 27...but that had to do with going from high altitude to extended intervals at FJR nominal speeds in the isolated flatlands.

 

[Geezer]

One thing not already mentioned is a possible dirty injector or two. If one or more injectors is dirty then the power would decrease and you'd be twisting the throttle a little more to get to your normal riding experience. You did mention a possible decrease in power. A good injector cleaner, like Techron, might help.

I had a similar drop in mileage during the first year of FJR ownership, but for me I know it was me twisting the throttle more and nothing wrong with the bike.

 

[Bounce]

And with the change occurring in August when we had some hot weeks after that, I don't think I can factor in the weather that much.

It's less a function of the weather than a function of when/if the stations you use switch to a winter mix for their fuel. Often the winter mix gets worse mileage. Sadly, in my area they use a winter mix year round because of EPA issues.

 

[SkooterG]

And with the change occurring in August when we had some hot weeks after that, I don't think I can factor in the weather that much.

It's less a function of the weather than a function of when/if the stations you use switch to a winter mix for their fuel. Often the winter mix gets worse mileage. Sadly, in my area they use a winter mix year round because of EPA issues.

I used to think that way Bounce, but not any more I used to think my winter fuel mileage went down because of the winter blend fuel. Well, it turns out it's the summer blend fuel that is oxygenated for less pollution and so therefore the worse blend. Winter blend is the 'normal' fuel. At least here. And most other places as far as I know.

So I had to conclude it's the colder air, or higher air density leading to increased air resistance and less fuel mileage. I'm sure the longer warm-ups don't help either.

 

[Intech]

Probably the wrong type of air in the tires or using the wrong oil.......

 

[odot]

I'd say yer right but yer a pats fan.....

 

[HotRodZilla]

Well, I don't know what's up with Skooter's bike, but at 8k, my plugs are ready to be changed. The bike picks up vibes and she runs like crap. I went over once being lazy and testing this theory. The check engine light came on, on the way home from a trip and there was a definite decrease in mileage. However, if your under your 8k interval, that shouldn't be your problem.

Could be a sticking break pedal, and inspect that those guys put the wheel on and the spacers in the right order.

Could just be that your becoming accustomed to the bike and are on the throttle harder. Sometimes I get irritated that my pegs seem to drag so much, but I realized I've gotten much faster than I was...So, mileage suffers and I don't care.

Honestly, I don't know how you were getting 48mpg on a regular basis. My '07 hovers around 42mpg. I can get 48-50 in the mountains though.

And Skoot is wrong about gas. It's the winter blends that "oxygenate" and decrease mileage. If he could read, it says so right in the pumps. BUT in his defense, it varies by area, I'm sure.

 

[SkooterG]

And Skoot is wrong about gas. It's the winter blends that "oxygenate" and decrease mileage. If he could read, it says so right in the pumps. BUT in his defense, it varies by area, I'm sure.

Not sure where you are getting your (mis)information from...............

Here's some good reading for you: https://blog.gasbuddy.com/posts/A-crash-course-on-seasonal-gasoline/1715-401024-239.aspx

A couple notable pieces:

With the added butane in winter gasoline, you may notice that fuel economy suffers until the warmer months, when refiners cease using as much butane in each gallon.

Other reasons for higher prices are added oxygenates. These are also added to summer gasoline to lower the RVP number.

I was mixing apples and oranges a bit. Ethanol is an oxygenate so oxygenated fuels are around all year long. The big thing with summer and winter blends is the RVP, or Reid Vapor Pressure. For places needing the summer blend, the goal is to reduce the RVP in hotter temperatures. And that should be standard across the board.