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Discussion Starter · #1 ·
I have a 2009 GTX 550F, I was getting about 10MPG, last year it went down to 7MPG, now it's at 5MPG with near perfect riding conditions. I'm riding at low altitudes and 0 to -10C. I've had the carbs cleaned twice this year(once I did them myself then took it to a mechanic) It starts perfect,idles normal,don't see any noticeable loss of power. Spark plugs are dry and dark brown, clutch seems to be working normal, new belt adjusted to proper tension. I've changed intake boots, checked track tension, changed all bearing. I'm at a loss as to what to try next.

Any suggestions would be greatly appreciated
 

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I have the same thing with a 600 did you change gearing or helix in secondary. One thing I replaced on mine was o rings in float when I inspected them they where hard a brittle. Haven't had snow to see though
 

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Discussion Starter · #5 ·
Haven't changed any gears or helix. I had carbs cleaned by mechanic, I'm hoping he would have picked up on the o rings

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- Have you been running ethanol free gas? I have seen ethanol gas give poor mileage.

- Have you done a compression check? Low Compression can equal bad fuel economy, in my experience.

- How many miles/KM?

Just my thoughts

Good luck
 

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Discussion Starter · #7 ·
I've been running regular 87 octane gas. I haven't done a compression test. It seems to work too good to be compression. It got 5700km

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is it possible that the plastic slides that ride on your helix in your secondary are shot preventing the clutch from shifting up, or is there something stuck in your primary clutch causing it not to shift up.. I know you said they seem to be working but you may want to pull them apart to see if anything is going on inside of them.
 

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Discussion Starter · #10 ·
Just took both primary and secondary clutch apart. Everything looks as good as new. Next thing is try carbs again.

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Discussion Starter · #12 ·
Im chasing a similar issue on a 700 summit (yes I know a zx) with flat slide carbs, did you ever figure anything out here?
Not yet. I've checked the clutch and they were like new. I checked fuel pump and found nothing. Only thing I got left is compression. I'm at my wits end with it.

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When the carbs were cleaned,did you remove the float needles to see if they stick in the seats

Normally you would not have nice plug color and would have some loading up at low rpms

130/cold is good compression for the 550 at lower elev

Belt has how many miles on it?
 

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Discussion Starter · #15 ·
When the carbs were cleaned,did you remove the float needles to see if they stick in the seats

Normally you would not have nice plug color and would have some loading up at low rpms

130/cold is good compression for the 550 at lower elev

Belt has how many miles on it?
belt is new, less than 200 km on it. What do you mean by loading up?
 

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Discussion Starter · #17 ·
After hundreds of dollars, and endless hour of research and experimenting I finally resolved the problem of poor mileage...... it was a simple pin hole in the gas line from the fuel pump to the carb. It was only leaking when I was riding. Thanks everyone for all the help

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My gtx 500ss is hard as well. 60km/19 liters. Can see it being a gas leak on mine cause it builds up so much pressure in the tank I would see it or smell it when parked. I’m from NL as well
 
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