F1 sensor light

It will always show 3 bars, even if the T-stat is stuck in the open position (common) your getting really poor mileage.
When tuned properly, and all the parts where they should be, you should be getting high 40's to mid 50's mpg.
I'm wondering if your bike is not tuned correctly, which is why someone convinced you to remove stuff seeking a solution?
 
No, no one convinced me to remove them. It is my experiment. I've done all it takes to improve the mileage like cleaning the little hoses under the air box (whatever the called). replaced the thermostat, used different fuel types, and other things I don't don't recall now. The consumption stayed the same. I gave up and accepted it as is.
I did replace the fuel pump in the beginning though.
 
My bikes was running well. First one had never been balanced. I asked the dealer (this is way back). "They don't need to be balanced, the engine management system takes care of that, sir".

Nevertheless, my old carbtune that I'd used with the 1100 carbs, was sticking so I bought a new one and bit the bullet. I'd never balanced the starter valves on a fuel injection engine before.
I'd read up, I knew what to do, a chatted with Larry, and he had a better way - so I did that. No, they weren't far out. Well three of them weren't. But goodness me. What a grin that brought to my face when I opened the throttle. I'm not one for yelling out. I did it once when after a lengthy period of trapped sciatic nerve I managed to walk to the top of a mountain again, pain free.
After balancing, riding the bike was the second time. Yeeeeehaaah !! So smooth, so fast. And the fuel consumption got up above 10km/l = about 45 UK miles per gallon. And it is still about that on longer runs. about 9.5+ / 43mpg if its on the twisty windy undulating slow/slow/quick/slow/quick yorkshire dales.
 
FastST said:
I gave up and accepted it as is.
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Your fuel consumption is high in my opinion. Something is negatively affecting your fuel consumption. It may not be engine management, it may be mechanical.
jfheath said:
And the fuel consumption got up above 10km/l = about 45 UK miles per gallon.
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10 Km/L is about 28 miles per UK gallon. That would dis-satisfy me greatly.
If you meant 45 miles per UK gallon that is about 16 Km/L.
 
FastST said:
Mechanical? Any ideas? I had this bike for over 5 years and 45k miles never saw the averg over 37 m/US gal on a good day, lol
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My average since new is over 46 miles per US gallon. That is in-line with what many report here so yours seems low to me.
Off the top of my head without giving it any thought it could be anything from one or more or all brakes causing increased resistance, SMC problem, wheel bearings, tire pressure, slipping clutch (slave cylinder, clutch lever incorrectly assembled), thermostat.
 
Andrew Shadow said:
My average since new is over 46 miles per US gallon. That is in-line with what many report here so yours seems low to me.
Off the top of my head without giving it any thought it could be anything from one or more or all brakes causing increased resistance, SMC problem, wheel bearings, tire pressure, slipping clutch (slave cylinder, clutch lever incorrectly assembled), thermostat.
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I replaced the t-stat, replacing brake fluids every 2 years and checked the SMC, no resistance from brakes, pressure mostly at 42/42, nothing you mentioned.
Checked the T-hoses under the air box (were clean) and cleaned the injectors. Nothing changed. I said, I'll ride instead of chasing the invisible "problem".
 
Andrew Shadow said:
Your fuel consumption is high in my opinion. Something is negatively affecting your fuel consumption. It may not be engine management, it may be mechanical.
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High but close to what many have reported with code 25/26 on. His code warning may have disappeared, but he may still run under knock safe mapping.
 
I'd be more concerned about you over working your ECU by your modifications, and causing it to fail, since they are really hard to source now since they've gone obsolete.
Your airbox experiment may have just confused the ECU and your invisible problem is still there, the ECU just may not see it and throw a code now.
 
MidLife said:
High but close to what many have reported with code 25/26 on. His code warning may have disappeared, but he may still run under knock safe mapping.
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No, it doesn't run under knock safe mapping. When the FI lit on, I could feel a little kick and had to give some more gas. It is running now the same way as when the FI was off and very lively.
I have the 35-37 mpg since day one when I bought the bike with 8k miles on it. And yet the FI was never on. FI light came much later and is not constant. It can disappear for few months and suddenly reappear back again. Especially at the end of a long day ride. Yet the fuel consumption stays the same no matter.
It leads me to believe that all 3 issues (FI, Fuel, Snorkels) are not related. There is no guarantee that it won't reappear one day.
 
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FastST said:
No, it doesn't run under knock safe mapping. When the FI lit on, I could feel a little kick and had to give some more gas. It is running now the same way as when the FI was off and very lively.
I have the 35-37 mpg since day one when I bought the bike with 8k miles on it. And yet the FI was never on. FI light came much later and is not constant. It can disappear for few months and suddenly reappear back again. Especially at the end of a long day ride. Yet the fuel consumption stays the same no matter.
It leads me to believe that all 3 issues (FI, Fuel, Snorkels) are not related. There is no guarantee that it won't reappear one day.
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Interesting you had to open up when the FI came on but there was no added consumption. Plugs looking OK?

You may want to give balancing a try per @jfheath.

Did you also check the vacuum line to the fuel pressure regulator?
 
MidLife said:
Interesting you had to open up when the FI came on but there was no added consumption. Plugs looking OK? Yes, I replaced them at about 20k

You may want to give balancing a try per @jfheath. Not sure what you mean by it

Did you also check the vacuum line to the fuel pressure regulator? I did (if you referring to the ones under the air box)
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please see above
 
FastST said:
please see above
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Balancing the Starter Valves as suggested above by @jfheath

F1 sensor light | ST1300 Related

It will always show 3 bars, even if the T-stat is stuck in the open position (common) your getting really poor mileage. When tuned properly, and all the parts where they should be, you should be getting high 40's to mid 50's mpg. I'm wondering if your bike is not tuned correctly, which is why...
www.st-owners.com www.st-owners.com

Yes, the lines below the airbox, but specifically the one to the Regulator. But could also be the Regulator itself, or kink in the fuel return line from the regulator.
 
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