meanhawk98

so a few weeks ago i posted that i changed my plugs gaped them at .034 ever since my milage went from around 100 to about 75 to 80 miles to a tank. so i ran a few tanks though it and no improvment,,could plugs do this and if so why?

nath981

that sucks. I go about 125 before low fuel light which has been fairly consistent since I bought in 2000. Oh, I forgot about the ethanol ****-fuel. Mine dropped to 115-118 miles before the fuel light at some point with the ethanol. I bought some stabil and mixed up a container of 1/2 stabil and 1/2 two stroke oil and put a capful in per tank full and that brought it back up to 125 miles to light. Also, I always fuel sitting on the bike so that it is straight up to fuel to the very top so that could make a difference too. One other thing is that some stations could be using more than 10% ethanol as it says at least 10%.

I'd say set your valves, tps, sync carbs, iridium plugs, and see what you have for jets and carb slide settings. Also, jack your bike up and see if the wheels spin freely with no restriction from bearings or brake drag, tight and or bad chain.

Did you try altering your riding manners to see if a judicious throttle helps at all? not that i would ever recommend that kind of riding.

aja

Is that around town? I run my plugs at .35 and get at least 115-120 between fill ups, mostly highway miles but some through town.

meanhawk98

ya its mostly city but even when i was pulling 100 or 90 to a tank was city tom and all i did was change the plugs to the iridim factory MGK pluch gapped at.034 and wham bam thank you mam there went my milage, im completely confused my riding style is the same to.i really would like my milage back espeacally since gas is going throught the effin roof!

saige

dont gap,check gap or touch anything around the gap at all with a iridium plug,it will ruin the finish on it and can ware out faster.
follow thru with everything nath981 said,should get you back on track with getting it back up there in miles.

meanhawk98

ok i agree with that but how could it change by the just changing the plugs? i mean it was all find before, in theroy i shouldnt have to go through all that if all i did was change plugs, should i try a new set without gaping them?

NHSH

I would also add to nath981, check tires pressure! Spark plugs should not make such a noticeable difference.

nath981

if all you did was change plugs, then certainly change to a new set. I didn't gap or even check the gap other than visual inspection. Plugs are relatively inexpensive at advance auto and similar, or if you didn't throw the old plugs away, you could even reinstall them as a test. Could be that or if you're fueling at the same place all the time, you might try another stop, diff company, hopefully getting gas from another supplier.

Another possibility is that in the process of changing plugs, you may have damaged a rubber plug boot or two, esp if they're old and likely to crack. You'd be able to tell this if you ride in the rain for a while or douse the engine with a garden hose with engine running because it will start missing or even shut off, or the easier way is have someone rev the engine while you insect the plug boots and wires in the dark so you can see any arcing. Or run your fingers along the plug wires/boots and see if you can electrocute yourself.

Sometimes these superhawks can be stupidhawks as little changes can have significant negative effects that seem implausible. It's most likely that the plugs or wires are the culprits to make that much diff all of the sudden, but correlation is not always causation, at least not the perceived or obvious correlation.

aja

The only way I can see a plug causing your problem is 1) a damaged/fouled plug or 2) somehow the wrong plugs were given to you.

As far as checking gap, I always check mine, I don't care of they're iridium. If they are far off, I return them for another set, I've actually had 2 sets come with bad gaps, one at .29 and one at .40, so that tells me they were mishandled some time or not gapped right from the source.

Other than that, I would be at a loss. Do you let it warm up for long periods of time? Sit in traffic a lot?

RWhisen

From NGK website:

"In most cases the factory set gap should conform to your vehicle specifications. However if it is necessary to widen the gap, do so with a tool that only pulls back on the ground electrode without touching the center electrode or the porcelain. To close the gap on a plug, gently tap the plug, electrode first on a hard surface."

NGK.com - Spark Plug 411

zxbud