Not getting great gas mileage

I picked up a 2007 VFR800 with about 60k miles on her last week and had just finished the first tank on gas. Looks like a full tank yielded about 120 miles, which means it's about 23 miles to the gallon. Sounds like it should be a lot closer to 40 mpg, even for all - city riding. I have no prior service records of bike maintenance, but it sounds like previous owner took good care of her. So given that all fluids are OK (bike was serviced before sale, and verified), what could be causing lower then usual mpg? What should I look into? Thanks

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I get about 280-300km per tank.

Check your air filter and that you're not riding in VTEC all the time first.

Welcome to the forums!

 

Sounds like that is a lot of fuel consumption. Hell, my old 71 Pontiac did not much worse than that. To be honest, I haven't got a clue what mileage I get. I have never worked that out in the 200K km I have put on mine. But I do think I get far better than that.

I agree with Jeff on both issues. They are the easiest to eliminate. It is easy enough to get caught up in listening to that fine music by cranking the throttle. Keep an eye on the air pressure in the tires and make sure there is no unnecessary drag on the brakes.

You might also want to check the plugs. With that mileage, it is not unheard of to see where someone would maybe change the plugs out. If that's was done knowing the bike was going to be sold, they may have cheaped out.

 

tune up, syn oil change

 

What engine temperatures are you seeing when fully warmed and riding?

 

Check/ replace air filter and plugs. Make sure the idle is not too high. Is the bike coming up to temp? You should reach 170-180F within the first 2 miles of riding if not your thermostat could be stuck open.
Your fuel injectors could be dirty or leaking causing your issues but those are a pita to remove and have cleaned.

 

LOL it's a V-tec thing. mileage on those models are all over the place, but yea I agree , it should be doing a bit better.

 

I get about 145-155 miles on a tank of mixed spirited riding using 89 octane.

 

Does it have a Power Commander in it? Might be running really rich through out the RPM range. Not only bad mileage but carbon build up could become a problem too.

 

Thanks for replies, everyone. I am going to change the air filter and spark plugs - then see where that takes me. Just waiting for the Haynes service and repair manual to come. I'll post updates as I make progress. Thanks again!

 

Also, to answer some questions: she's completely stock, and temp is usually between 180 - 220 if I recall numbers correctly. Going to make note of it during the commute.

 

You might take a look at the vacuum line to the fuel pressure regulator; there is a diaphragm in the regulator that reduces fuel pressure in response to increased intake vacuum (so the fuel injects at a constant relative pressure). If the diaphragm fails, you can suck fuel down the vacuum line, and the fuel pressure will be correspondingly higher as well, so more volume injected and higher consumption. Check the vacuum line for any liquid, make sure the line is intact, and check the regulator will hold a vacuum (e.g. using vacuum brake bleeder)

 

You don't look like these fellas do you? eaceful:

 

Common now. Me and brudda Bubba have each lost 5 pounds.

 

You meet the nicest people on a Honda!

 

For reference, my 2004 with PCIII/dynotune gets around 38-40 mpg when I ride it pretty hard.




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From a re read of the OPs original post. I've also come to a conclusion since it was the first tank. it could be a riding style.. Give it more than one tank before fiddling. I've rode with folks same route and their mileage was different, we first had a discussion about engine tune. what tire and gearing etc. but they were running too good to be fouled up, so we concluded it was a riding style.

 

It also wouldn't hurt to verify fuel quantity...it's a 5.8 gal tank, how much was put in, and where was the gauge at before/after filling?

FYI-I averaged around 38-40 mpg on my 6th gen with very hard riding at high altitudes.

 

I had the same issue and synchronised the starter valves. Already feels like it's not drinking gas but will properly test with a new tank full but I don't get that petrol smell when running like I had before.

 

I had bad mileage for a while, and couldn't work out why.
Then I remembered that last service I was too lazy to clean the K&N air filter so I installed a cheap Chinese one I had laying around.
Reinstalled the K&N and its back to normal.
Made a difference of 50kms to a tank.
Should have known better.