New Plugs=Worse Mileage?

[VMAX NV]

I replaced my plugs with stock NKGs. I checked the gap with two different types of gauges. The bike seemed to run better afterwards but the fuel light came on at low 60 miles! The next tank it came on in the low 80s. Previously it had always been high 90s. I'm not riding it really hard or anything...

Could plugs effect the mileage that much and why?

Also what are the effects of the gap being too wide or narrow?

Thanks.

 

[alorio1]

Maybe you are not consistent on topping it off fully on every fill-up..I find myself either running it over or just not getting the fuel to the neck so I can see it. I really can't see changing plugs having a great impact on gas mileage.

 

[SpecOps13]

My 94 must have some restriction in the vent. Nothing major, just affects the final fill to the top. I keep cans of redimixed fuel so, when I fill it, I wait a few seconds and then I can put more in. Over and over till it's not dropping any more.

To also answer the plug question, it's not unheard of to get a bad plug now and then.. But if the bike runs good, that's out...

Did you buy the gas at the same station when the mileage dropped. could also be bad gas...


Good Luck,

 

[firefly]

I use chevron all the time & once in a while put a different gas like76, Mobil or shell, I noticed the shell gave more miles vs chevron ~ 6 more miles from fuel light to fuel light. I still use chevron. also consider when they change from winter gas to summer gas & not to mention % of ethanol in the gas. new plugs should give better gas mileage.

 

[eat crow]

perhaps a brittle plug wire?????

 

[tugla]

maybe one of the plug wires is not attached properly? worth a second look or check in the dark for arcing.

 

[94 V-Max Rider]

I replaced my plugs with stock NKGs. I checked the gap with two different types of gauges. The bike seemed to run better afterwards but the fuel light came on at low 60 miles! The next tank it came on in the low 80s. Previously it had always been high 90s. I'm not riding it really hard or anything...

Could plugs effect the mileage that much and why?

Also what are the effects of the gap being too wide or narrow?

Thanks.

No, new plugs will not cause decreased gas mileage. If I was to fathom a guess as to what's happening with regard to your varying gas mileage, assuming that the bike is running properly, I'd guess that the fuel sensor is at fault.

 

[jfeagins]

I'm guessing your fuel source just added a larger % of corn squeezin's to their mix. Just a 10% mix will lose nearly 5mpg from what 100% dino can accomplish. JMHO.