Tune Up Question: average MPG going down

[StratTuner]

My MPG is sagging lately, and I'm not sure why.

If I take my NC into my mechanic and ask him for a "tune up", is there anything he can really do?

I've put on a new chain and sprockets... could that make a difference?
I shift at 3K pretty consistently.

I've lost 10 lbs, so it's not rider-weight.

 

[Jeff762]

Could be the fuel, the refinery may be adding more ethanol. Just a thought

 

[StratTuner]

in California, I think they do that in the summer? Hmm...

I"m taking it in to the mechanic tomorro, so I was wondering what I could ask him to check in addition to replacing the brake pads.
Electronic Fuel Injection means that there isn't much for him to adjust? Is that correct?

Also, if he hooked up the "data port" (whatever that is?) to a machine, would the NC tell him what was wrong?

 

[Mr_Krabs]

Could be different things. How much is it being reduced by? Anything new or different like tires, changes in tire pressure, etc? Even with the best of mileage routines just simple changes like overall weather can affect mpg by 5% or more.

Shorter commutes combined with colder weather, which tend to make people want to ride shorter distances can greatly reduce mpg. Basically unless it's significantly below your old average and sustains that for several tanks or more it's hard to narrow down exactly what's causing MPG loss.

Remember too that this is all a percentage gain or loss. So a 3-4 MPG loss is still less than 10% which is statistically insignificant in the short term.

 

[Naked_Duc]

Is temperate affecting your MPG? The air temp is dropping and the mornings are getting foggy here in Seattle. I noticed a 5% drop in MPG in October versus September. Below is my monthly average.

Oct '12 - 65.3 (bought on 10/25, 1 fill up in Oct)
Nov '12 - 66.8
Dec '12 - 68.1 (600 service done)
Jan '13 - 67.0 (Coooold month)
Feb '13 - 68.8
Mar '13 - 70.3
Apr '13 - 71.9 (installed tall windscreen)
May '13 - 73.6
Jun '13 - 74.1
Jul '13 - 75.0
Aug '13 - 74.9
Sep '13 - 73.0
Oct '13 - 70.0 (cold and fog returns)

 

[SergeantChuck]

Mine has gone down since I bought the bike but I believe it is because I ride it differently than I did when I first purchased it. In the beginning I was nice to it. I ride it hard now. I think I cared about my MPGs and tried to stay under 70MPH and didn't gun it off of stops. It gets such good MPG that I don't think about it anymore. I ride it hard, I leave it idling when I make stops, and I'm riding well over 70MPH on the interstate. We have not hit the really cold yet so I cant tell if cold is having an effect. In my case, I'm the cause.

 

[Deleted member 1183]

The first thought that comes to mind is the Air Filter. How much mileage is on it ? It may well be time to get a new one. Apart from that there is little to go out of adjustment on these bikes. The only other thing I can think of is a clogged or partially clogged injector which is in need of cleaning ? Perhaps the spark plug gaps need adjustment or even replacement. If I think of something else I will get back.

 

[SergeantChuck]

Here is an article I ran across. Have no idea who wrote this.


Factors That Affect Your Bike Fuel Economy

 

[Spaceteach]

Strat,
Can you tell us how much your mileage is sagging and how long (how many fuel stops) it's been doing it? Is it gradually getting worse or did it kind of drop off all at once? Did you do any maintenance or mods like an oil change where you used heavier weight oil or modifying/adjusting your windshield? Have you raised the rear end off the ground and spun the rear wheel to see if it is any harder to turn than it used to be? Have you noticed any reduction in power or roughness in the engine?
I'm guessing these are the types of questions your mechanic will ask, so it would probably be a good idea to think about them and be ready with the answers.

Hope this helps,
Bob

 

[StratTuner]

Very good posts, gentlemen. Thank you. I'll ask him about replacing the spark plugs. Can you really clean fuel injectors?

My overall sense is that I used to hit around 75mpg regularly, but now it's 65.

	64	10/27/13	190.4	2.89	65.8	3.760	50%
	63	10/20/13	187.9	2.78	67.6	3.830	50%
	62	10/7/13	211.2	2.77	76.2	3.850	50%
	61	10/6/13	172.6	2.24	77.0	3.850	50%
	60	9/29/13	181.1	2.87	63.0	4.030	50%
	59	9/29/13	130.8	2.23	58.6	4.000	50%
	58	9/29/13	157.1	2.09	75.1	4.000	50%
	57	9/29/13	155.9	2.43	64.1	4.000	50%
	56	9/29/13	174.4	2.66	65.5	4.000	50%
	55	9/29/13	154.4	2.53	61.1	4.000	50%

54	9/29/13	124.8	2.00	62.5	4.000	50%
	53	9/29/13	199.3	2.91	68.4	4.000	50%
	52	9/26/13	186.1	2.47	75.3	4.000	50%
	51	9/22/13	160.0	2.47	64.9		50%
	50	9/22/13	98.7	1.88	52.6		50%
	49	9/22/13	186.4	2.82	66.1		50%
	48	9/22/13	168.5	2.35	71.7		50%
	47	9/22/13	161.4	2.58	62.6		50%
	46	9/18/13	188.6	2.83	66.6	4.150	80%
	45	9/15/13	142.1	2.15	66.2	4.090	50%

 

[StratTuner]

looking at my own data, it seems it's been in the 65mpg range for a while.
Maybe that's just what the engine is "settling" in to. (now there's an UN scientific expression).

I can't make it hit 80 anymore even if i drive the whole tank at 55mph in mostly 6th gear (canyon riding).

I take care of it, so I guess I'm doing the best I can.

 

[davidc83]

It could be winter blend versus summer blend in the gas. All states(except maybe Hawaii) switch over to a winter blend (usually the gas companies switch in late Sept-early Oct). I see a difference in fuel mileage (lower) in the winter compared to the summer (I don't let my vehicles 'warm up' in the winter-my road is 2 miles long at very slow speeds before I get to the highway, it is always warmed up by the time I get to the highway) in all my vehicles-both bikes, jeep, truck, car.

 

[MZ5]

It could be winter blend versus summer blend in the gas.

This seems most likely to me, barring lower tire pressure or a change to thicker oil or something. Note that winter blend fuel is not necessarily the same as simply adding or changing the alcohol content.

 

[StratTuner]

OK... back to the other question...

Is there something I can ask my mechanic to service today? Spark Plugs? Fuel injectors?

I keep the tire pressure about 3lbs OVER spec. I like the better MPG.
I use (gasp!) Rotella T6 oil with a K&N filter.
I put in a K&N air filter myself this month.

 

[L.B.S.]

OK... back to the other question...

Is there something I can ask my mechanic to service today? Spark Plugs? Fuel injectors?

I keep the tire pressure about 3lbs OVER spec. I like the better MPG.
I use (gasp!) Rotella T6 oil with a K&N filter.
I put in a K&N air filter myself this month.

The question is too open to variables (IMHO) Strat.

What is your mileage? When did you have the last service? Was it a more comprehensive one, with a valve adjustment? When is the next one due according to your owner's manual? If you are close enough to the next one to wait a few miles or weeks, and have the work done all at once, instead of spending money to have new spark plugs (or whatever) done now, only to be taking your bike in for that scheduled maintenance which would include new plugs in a short period of time again, it doesn't make sense to worry about what sounds like to me, a miniscule perceived drop in fuel economy between now and then.

Other than what you are experiencing with a slight economy drop, how is the bike running in general? A dirty or clogged injector could be resonsible for an efficiency drop sure, but on the other hand, all my experience with EFI and bikes has been they work just fine until they clog or malfunction, and then the bike runs sucky, and you *know* there's something going on. For me it's never been any gradual slight lessening of mpg's.

New oil, old oil, type of oil, meh, I don't think it could be any measurable thing as far as economy drop notice. Same with air filter, unless it's plugged solid with dirt, and if you just puit a brand new one in, then that doesn't sound like a sorce of lower mpg's.

Usually as soon as an owner utters the phrase: "a tune up" to a mechanic, it is a licence to over charge you for either duplicating something that was already done last service, or is about to be done next sevice, or a blatant unneccessary addition of parts and labour ie: the Placebo Effect. Not to tar all mechanics and/or Dealers with the same brush of course.

It's literally, one of those "Your Mileage May Vary" turns of phrase I'm afraid. Honestly, I don't think the +/- numbers you believe are in evidence are worth getting too concerned about, but that's just me

 

[670cc]

Right on, L.B.S. Requesting a "tune up" is like handing a blank check to the service dept. It means put in a bunch of parts that didn't need replacement.

Greg

 

[Deleted member 1183]

I am still curious as to the mileage on your bike Strat. I have K&N filters on Two bikes. On my FJS600 (since traded for the NC ) I replaced a dirty original filter with a new K&N. I immediately started to monitor fuel consumption on the bike. Over a reasonable period I found that the K&N gave exactly the same fuel consumption as the soiled Original paper filter.

On my 690KTM I again used a K&N. Again, there is no difference in fuel consumption. I had expected an improvement on both bikes as K&N clearly advertise this on their packaging etc., but there was absolutely no improvement on either bike. I wrote to K&N complaining about the FJS filter as it was poorly finished, and would not fit properly until I trimmed some moulding overspills off of it. I had absolutely no response from them. As I had sold the FJS I did not follow up.

 

[Spaceteach]

Strat,
The service manual says to inspect the spark plugs at 16,000 miles and replace at 32,000 so it may be worth having the mechanic take a look. If there was a major issue with a plug I would imagine you would have noticed some rough running or misfires, but you are probably close to the scheduled inspection interval so it can't hurt to check.
These days the most common way to clean fuel injectors is to add the cleaner to the fuel. Since most major brands of fuel advertise their additive package includes fuel injector cleaners (think Chevron Techroline, at least I think that's what they call theirs), you've probably been adding some cleaner every time you filled the tank. If you think they may be dirty anyway, it's just as easy and a whole lot cheaper to just add some cleaner to the fuel the next time you fill up. You can probably get it at WalMart, any auto parts store, or, if I remember correctly I think some gas stations sell it. If you decide to add some, make sure to follow the recommendations on how much cleaner to add per gallon of fuel. With a 3.77 gallon tank, it probably won't take much.
If you're coming up on the mileage where checking valve adjustment is recommended, and you don't feel comfortable doing it yourself, it would probably be a good idea to have that done.
All of the above with the exception of fuel injector cleaner are maintenance schedule items and if you are having the bike serviced because you are coming up on a service interval where plug and valve inspection is recommended, they shoul be done. As to whether or not it will increase fuel mileage, I don't have a clue. My NC has fewer miles on it than yours, so I can't speak from experience on this bike but I've never seen a mileage increase on other bikes I've owned after a full service. Hopefully, YMMV (and I mean that literally) !

Bob

 

[showkey]

LBS nailed it......


I say this with tongue in cheek.........It is more likely the prevailing wind direction and intensity has changed causing a slight preceived difference in in MPG than anything "wrong" with the NC driveline or engine.

If you were to anything the checking the valve adjustment is the only thing that has any merit. Tight valves with higher mileage will effect starting, performance and economy.

Data port interagation will tell you little or nothing if the MIL is not lit. Yes they verify individual sensor inputs but the bike still runs good so that is not likely to be any concerns or problems.
Injector partially plugged extremely unlikely as stated by others.


Your not running with those new saddle bags are you?????????

WINTER gas has a lot of merit:

Quote from site below-
"What’s the result? Well, basically, winter blend gasoline has a larger percentage of butane in it. And since butane is cheaper and has less energy, winter blend thus costs less and gives us a lower MPG when we burn it. So it’s a wash, right? Eh, maybe. Your vehicle miles per gallon typically will drop 2-8% when you start filling up with winter blend.

Last year they started winter blend in CA in October


http://www.popularmechanics.com/car...-blend-gasoline-whats-the-difference-13747431

http://itisscience.wordpress.com/2011/11/28/winter-gasoline-yes-there-is-a-difference/

 

[StratTuner]

OK... well i'm having the mechanic give it an inspection (yes, I know, waste of money) because I'm about to take it to Omaha Nebraska from San Diego... for Thanksgiving dinner with family!
The replies are very much appreciated. I had thought to use the fuel injector cleaner gas additive, but I wasn't sure if it was just snake oil.
Apparently it's not.
I'm determined to have the maintenance done on schedule and thoroughly. Thank you all for the thoughtful replies. I will go back and re-read them now.