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Low compression after 25.000 miles


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CLEAR case where you babied your bike to death. I know several people with 70k miles on an FZ/FJ-09 that wheelie Main Street on the regular. I've ran mine long and hard, use European spec Mobil 1 5w30 synthetic and haven't looked at my k&n air filter in 20k miles. 47mpg at a steady 90mph and not a puff of smoke... this engine just keeps begging for more!
47mpg @ 90mph? Downhill with the wind at your back right? 
I don't think it's fair to say because you rag the piss out of your bike and don't keep up with maintenance as well as someone else that they did something wrong. 
 
Sounds like maybe OP just got unlucky. Sucks that Yamaha won't help out.
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  • 1 month later...
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Sorry for long pause between replies.  I finally fixed the problem.  I had a lazy O2 sensor that was causing me to run rich.  I replaced sensor with another unit.  I had to cut plug off old unit.  I also replaced cam tensioner with a APE unit.  I am now running around 50 mpg based on computer.  I haven't not rechecked compression since.  Unit seems to be running good.  I appreciate everyone's feedback.
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Way to stay with it and figure it out, all the while ignoring the negative comments. I learned a lot from this thread. thanks 

Yup, this is a good thread for learning more about our bikes. 
I've  looked at the FJ O2 sensor hanging out there in the breeze and wondered of it's location might contribute to a short life. Rain, mud, and general road crap bashing it from all sides every time you ride.
 
I've replace few O2 sensors on my Subarus, and they lived in much more sheltered locales.
 
Thanks for educating us all on the intricacies of these devilish devices!
 
WRT mileage: I see a drop from 50mpg to 40 mpg when I run over 75 mph. Above 6k RPM in 6th forget about 200 miles per tank. More like 160 for me.
 
cb
1968 Triumph Bonneville 650
1971 Norton Commando Roadster
2002 Harley 1200 Sportster
2003 Honda ST 1300
2016 FJ 09
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Way to stay with it and figure it out, all the while ignoring the negative comments. I learned a lot from this thread. thanks 

Yup, this is a good thread for learning more about our bikes. 
I've  looked at the FJ O2 sensor hanging out there in the breeze and wondered of it's location might contribute to a short life. Rain, mud, and general road crap bashing it from all sides every time you ride.
 
I've replace few O2 sensors on my Subarus, and they lived in much more sheltered locales.
 
Thanks for educating us all on the intricacies of these devilish devices!
 
WRT mileage: I see a drop from 50mpg to 40 mpg when I run over 75 mph. Above 6k RPM in 6th forget about 200 miles per tank.
 
cb
 
I don’t think there’s a widespread problem with the o2 sensor. Mines been fine for nearly 50k miles.

Let’s go Brandon

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