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92 k75rt fuel consumption woes ...

scoobs

New member
My K75 has 120,000 miles on it and I've noticed that my fuel consumption has deteriorated quite dramatically. I used to get 220 miles per tank (50 MPG) but this has dwindled to a miserable 160 miles (35 MPG). I'm aware that the use of ethanol in the gas has an adverse affect on MPG but surely not this much?
I've installed a new air filter and spark plugs but this hasn't made any obvious improvement so would be thrilled at any helpful suggestions. I recall reading somewhere of a faulty sensor that can cause excess fuel to be injected into one of the cylinders but am unable to locate said article.
I average 15,000 miles a year and so any improvement will save me a decent amount of money.
Cheers,
Ian.
 
K75 Fuel Mileage

I filled up my 94Standard today and got 51 mpg, best since I bought this bike with 15K on it. Currently has 53K. I use fuel injector cleaner about three times a year and this year have 20K on the bike. I notice that fuel mileage varies a lot with the blended fuels we get today and also on the riding. When I run the freeway with either of my K75s the mileage will drop down to closer to 42/43MPG. With your mileage you might want to run some injector cleaner in there for three or four tanks in a row and see if that helps. I don't remember ever seeing an article as you mentioned in your post. If you find it or someone else does, please share that info.
:usa
 
Fuel Consumption Issues.

With 120K on the clock the injectors may need cleaning (professional).

My 90 K75Rt went from 40 to 55mpg after sending the injectors out to Mr. Injector.
 
Holy Cr@p!!!! sorry but I had issues with the sensor wiring three years ago when a mouse nested near my airbox while I was out of the country- I just taped it up and forgot about it as I had no obvious temperature control issues at the time. I've ridden +50k miles since then, goodness knows how much gas I've wasted :doh
Just put the ohm meter across terminal #10/ground and getting 2322 ohms with an ambient temperature of 71*F, which is close to the 2.5kohms listed on the trouble shooting link, so I don't appear to have an open circuit or direct short in the wiring. I'll test it again in the morning as the temereature is supposed to drop to around 45*F, then will run the engine until the fan kicks on as also suggested and recheck the resistance. I assume I'll have to reconnect the FI computer in order to run the bike, then disconnect again to take the readings?
I'll also investigate local options for getting the injectors cleaned, although I do run "Seafoam' through the tank before my regular oil changes.
Thanks to Y'all for your help, if anyone has any further suggestions please feel free to comment.
Cheers,
Ian
 
Glad yours was so easy to fix. I've been battling poor mileage on mine since I got it. Normally around 35 mpg but on highways with moderate speed, I can get 39 or so.
Replaced temp sensor - to get the fan working, intake rubber, new injectors, lots of gas treatment, balanced TB, checked and adjusted valves, new plugs and went over every thread on several forums regarding bad mileage. Pretty sure the brakes are not dragging. It has always started and run like a sewing machine.

Let me know how yours turns out.
 
Update

Okay, so the temperature sensor ohmed out correctly at various points on the scale- so it is working properly in spite of the sterling efforts of the local mice :)
I've pulled the fuel injectors (haven't seen any before but they looked dirty) and shipped them off to "Mr.Injector" as suggested.
I'll give further updates when I get them back in the bike and do a test run.
Thanks to all who've given advice on this matter.
Ian.
 
Help!!!

Okay, got my injectors back from "Mr.Injector"- reasonable turnaround time and well packaged !!
I refitted them to the fuel rail and installed in the bike, but it will not fire up :(
I remembered to reconnect the tank plug and the hook ups to the injectors, the fuel pump runs and I've got pressurised fuel at the rail- anyone got any thoughts as I'm hoping to take the bike to Florida on Thursday.
Thanks,
Ian.
 
Check the main plug to the EFI computer. Make sure that it is properly seated.

Do you have spark? Pull a plug and ground it to the engine. Crank the engine to see if you have spark.



:dance:dance:dance
 
Strangely enough, I thought about the FI computer hook up after I got to work so will check the connector in the morning. That sounds like the problem as I had disconnected it when verifying the output resistance from the temperature sensor and may not have got a good connection when I reassembled everything. :doh
I do have power to the spark plugs as I got a blue flame when trying to crank it with the injectors pulled- probably a good thing the injectors didn't work or I might have set the garage on fire !!
Maybe I'll get to Florida after all, I'll post an update tomorrow.
Cheers,
Ian.
 
Duh!!

Okay, so I connected the FI computer and the bike fired up- I'll report on any MPG changes when I get back from Florida :)
Ian
 
When connecting the plug to the computer, always put one hand on the rear of the computer (you must remove the right battery cover) . Since the computer is rubber mounted, just pushing from the front can allow the computer to flex in its mounts and not always allow the plug to properly seat. You MUST hear a distinct click as the connector locks into place. Failure to properly seat the connector MAY allow the bike to run, but will eventually cause all kinds of problems due to poor connections.



:dance:dance:dance
 
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What did the report on the injectors show prior to cleaning?

You may also want to check if your brakes are dragging
Also, When was the last time you greased/replaced the wheel bearings?
 
Back to the drawing board....

Well I gave the bike a good run this past weekend- 1000 miles round trip for the "Sun your buns" rally. Sadly the gas return remains the same at around 35 MPG, so while cleaning the injectors was probably necessary it hasn't solved my problem.
Any suggestions welcome,
Ian :drink
 
Have you ever put the bike on an exhaust gas analyser, or if one is unavailable, used the idle drop/starter button mixture check?
 
My bike ran fairly well for 8000 miles after I bought it last year, and I averaged about 38 mpg.

I checked and adjusted the valves last spring and that instantly brought me up to 45+ mpg, sometimes 50 mpg with good ethanol-free fuel.
 
What is that?

Something that is only relevant when everything else is properly adjusted (valve adjust, throttle sync, etc).

When the bike is fully warmed up and running, pressing the starter button should not cause the idle to rise (if it does, the bike is running lean). Inserting the altitude plug should not cause the idle to rise (if it does, the bike is running too rich). Ideally, both these tests should cause the idle to drop slightly.

ONLY APPLICABLE IF EVERYTHING ELSE IS ADJUSTED CORRECTLY AND NO VACUUM LEAKS!!!



:dance:dance:dance
 
Well it is clear, Lee, that I need to get my bike to you, so that I can learn about it.

What would novice brick owners do without you?
 
Still no good.....

I replaced the "Z breather hose" as suggested somewhere on here but no improvement :(
I've contacted a couple of local (150 miles away) repair shops but they claim their diagnostic equipment is too modern to use on my bike.
HELP!!!
Ian.
 
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