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I've had my bike now for a little over two years and I can't seem to get more than 35 mpg. This is what I have done so far:



New Air filter

New fluids

New plugs

Harley 883 mufflers

Fuel Filter

New brakes (front and back)

LED tail lights

New ACVs

New fork oil and seals



I put everything I did for completeness, knowing they don't all relate to mpg.

Checked the brakes for excessive rub, they were ok.

I cleaned the carbs, when I put in the ACV's



I'm at a loss, almost everybody is getting 45 to 50mpg, or so it seems.



Any ideas? Other than that bike runs great and strong.
 

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...and on that idea, what would be the most economical speed to run our bikes at? Assuming a straight level road, no wind, 180 - 200 lb driver. Realizing there may be differences for the respective diplacements and gear ratio's our bikes have. Any ideas?
 

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You cleaned the carbs but did you check the float levels? I've been reading on how to clean the carbs and it was noted that float levels need to be set or mileage will suffer.
 

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I've had my bike now for a little over two years and I can't seem to get more than 35 mpg.



I'm at a loss, almost everybody is getting 45 to 50mpg, or so it seems.



Any ideas? Other than that bike runs great and strong.


You could try doing a compression test,,low compression would probably result in lower than normal gas mileage.
 

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I've had my bike now for a little over two years and I can't seem to get more than 35 mpg. This is what I have done so far:



I put everything I did for completeness, knowing they don't all relate to mpg.

Checked the brakes for excessive rub, they were ok.

I cleaned the carbs, when I put in the ACV's



I'm at a loss, almost everybody is getting 45 to 50mpg, or so it seems.



Any ideas? Other than that bike runs great and strong.




Make that 45-54 MPG on my Silverwing.



You changed the mufflers; did you rejet the carburetors?
 

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Are the carbs synced right and are you larger than small.



On a naked bike a big guy would have wind resistance due to size and drag due to weight.



But I have also seen some pretty big guys on full fairing bikes and they get their 50mpg.



Riding to fast or to slow will kill the mileage too. Anything over 70 and my mileage starts dropping off. Anything under 40 isn't helping it. But my around town mileage is 44. Everything else if there isn't massive wind is 44-50.
 

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When I first got my bike with dirty carbs and semi-dragging brakes it would get around 39 mpg.  35 is pretty low, have you checked to make sure your odometer is accurate?  
 

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The Harley 883s will increase your fuel consumption.I've just changed back to stock exhausts for this reason.



You can tune them a bit and it will help,



http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=9&t=324&p=1667&hilit=883#p1667



This weekend I've done around 300 miles and averaged around 48 Mpg UK gallon but there was a lot of spirited 70+ mph riding and hard acceleration as I was with several modern fast bikes.I can get well over 50+ with gentle throttle and limiting to 60 Mph.

I have had as low as 38 mpg UK gallon with none baffled Harley 883s.I doubt re-jetting will help as it may just alter where the power is delivered.





HTH
 

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That would be part but I doubt all of the reason it's so low. Bound to be something amiss in the carbs or sync between them, you sure it isn't dripping any gas from the overflow tubes? Or that the petcock shuts completely off?



Could also have got a bad plug or they aren't gapped correctly. Also - have you replaced the reistors in the plug caps yet?
 

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But you agree the muffler is a likely candidate?




I think so but as per other posts the carbs may need more attention as well.I have two sets of Harley 883s,one set has a sort of half baffle and they can return around 42/46 MPG UK but the other straight through pair gobble the juice massively.
 

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Last year I was only getting about 35 mpg on my naked GL500. This year I installed new plugs and started using Seafoam in my gas (I did recently change to Barrymans). I get 50+ mpg consistently now. I did add a fairing to my bike this year, but I also lost 80 pounds so they cancel each other out.
 

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Last year I was only getting about 35 mpg on my naked GL500. This year I installed new plugs and started using Seafoam in my gas (I did recently change to Barrimanns). I get 50+ mpg consistently now. I did add a fairing to my bike this year, but I also lost 80 pounds so they cancel each other out.


The fairing on the GLs rather than decrease fuel consumption actually improve it by their aerodynamics reducing the bike's drag.Even the small bubble fairing on my CX helps a little as does the slightly bigger Fabrini one on my other CX:)
 

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stupid question did you ever think about his tires and pressures? That can make a huge difference! My bike had a bald tire on the front running at a disgusting 21psi and the one on the back had a slow leak so every day or 2 it would go from 40psi to 25psi my handling was really shitty and it only was getting 32mpg New tires correct pressures held constant with abusive stop and go driving it's way closer to 42mpg with dirty carbs and rusty gas
 

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I think so but as per other posts the carbs may need more attention as well.I have two sets of Harley 883s,one set has a sort of half baffle and they can return around 42/46 MPG UK but the other straight through pair gobble the juice massively.






Using 1 imperial gallon equals 1.2 US gallons, that means 50-55 MPG (US) which is comparable to what I get with the stock muffler. So the lack of baffle apparently would make all the difference.
 

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35 mpg seems too low for it to just be mufflers.  I have harley one's also with the home-made baffles/screws and I still get 45-46 mpg.
 

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my gl500i full dressed with fairing side and top box on i get 58.5 per imp gall Air pressure 28psi both tires.

I have to say i thought this sounds low for the tyer but that's whats on the label... what do u have in yours...
 

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35 mpg seems too low for it to just be mufflers.  I have harley one's also with the home-made baffles/screws and I still get 45-46 mpg.


As I have found out,not all 883 mufflers are equal.The partially baffled ones with tuning are better than the straight through ones with tuning.

There is a relationship between the valve timing,cam profile and back-pressure from the correct exhausts that aids in the scavenging of exhaust gases from the cylinders that also causes a negative pressure inside the cylinders that is used to aid the induction of fuel vapour.

The whole system including the air-box and the crankcase breather recycling was innovative at the time not only for these motorcycles but in automotive engines.It's now commonplace and even more refined on in modern cars and bikes with engine and exhaust sensors etc.



Honda obviously did a great job of making this complete system,especially for the time/era, so making any change to any part may well have a detrimental effect.
 
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