Understanding why my mpg is declining???

nectrplnt

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06,25k,new tires,very recent oil and filter change, recent coolant change, chain lubed and checked every 500mi new plugs 2k ago, valve adjustment at 19k, use 91oct. My mods are simple, pc3,yoshimura slipons, airbox mod and map.....runs great with zero complaints. Use to always get 38 mpg no matter what. Now I'm getting 33 and dropping. What gives?
 
It could be as simple as ethanol. How often do you check it ? I run 93 , no alcohol when possible. I have a Gen II. 90 up on octane.
 
Gen 1 is 87 octane. Also did you see a decline before or after the new map? Are you riding it the same? I have almost the same mods and was getting 46 average then I put on the r1 throttle tube and started averaging 42 just because I rode different. DO3 is also correct on ethanol. Winter gas is different than summer gas.
 
Gen 1 is 87 octane. Also did you see a decline before or after the new map? Are you riding it the same? I have almost the same mods and was getting 46 average then I put on the r1 throttle tube and started averaging 42 just because I rode different. DO3 is also correct on ethanol. Winter gas is different than summer gas.

I'll start using 87 and see what happens, always been on the same map since day 1, been riding as I usually ride..60hwy 40city

....air filter has recently been replaced.
 
I'm thinking I'm gonna get it tuned when it gets hot out. I don't recall a tune after I did the airbox mod and cut my pipes. Regardless after I did the mod, it still got good mpg, 38 avg
 
I would wait for summer and see if you see a difference. My buddy with a diesel see a 4mpg change from winter gas to summer gas. So it could be as simple as that
 
What did you install for plugs?

And it could be that you are just riding the harder as you get more used to it.
 
I'm going to agree with it being ethanol. In California there is no requirement to post any ethanol content. I think they are boosting the percentage quietly as ethanol cost less to make than gas. I've seen my milage drop lately as well using 87 octane.
 
What did you install for plugs?

And it could be that you are just riding the harder as you get more used to it.


stock plugs........im going to try some injector cleaner this weekend and wait it out till the summer when I get a tune and we get better gas. Hopefully that does the trick
 
Try a bottle of startron, great stuff to battle the corn in the gas. Look in the boat section at wallmart, one bottle last a long time.
 
Your wasting your money on fuel!
87 OCTANE!

I wish my bike got 33 to 38 MPG
 
You need to go on a long, smooth, 60 mph run and allow the fuel mileage to top off at 50mpg. It might take an hour or so, but be smooth and go on a long freeway until it does. Even with the mods you have, it very possible to achieve.

If it deosn't creep up to fifty, you have a fuel delivery problem.

My commuting in traffic fuel mileage is around 34 mpg, so once in a while I run it long and slow to let it smooth out.
 
check couple of easy things:

- tires are correctly inflated
- drivechain correctly adjusted
- with bike on mainstand check that the front and back wheels turn freely and that the brakes are not sticking/dragging
- clean airfilter( no blockages), (no fuel/vacuum leaks)_,
-make sure clutch is not slipping..
- perhaps do a compression test, low compression can affect performance and economy.
 
I have almost the same thing, 06 LE, around 20K miles, PCIII, with custom map, K&N air filter, full Hindle 4-2-1......and my MPG is 34-48 mpg, it's how I'm riding, at the time ? I haven't had my valves adjusted yet. Even though EVERYBODY says it's a waste to use anything above 87 octane, I've always ran 93
 
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