Perils of poor fuel quality...

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Zeets
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Joined: Thu Aug 19, 2010 6:42 pm
Location: Kensington (for now)

Perils of poor fuel quality...

Postby Zeets » Tue Nov 20, 2012 2:42 pm

My DRZ normally averages between 53 and 58 mpg, the last two tanks have been 45 and 46 mpg. Nothing else has changed, my commute is the same, the tires are aired up, and I even went to 10w-40 full syn for the winter months (down from 15w-50, semi-syn). Theoretically, my gas mileage should remain the same, or even slightly improve due to the more efficient oil and the cool dense air which automatically causes the a/f ratio to lean, a lean engine is a happy engine. Instead, I've seen a huge knock in economy with nothing other than the weather and the piss poor gas quality to blame. I guess I could clean my air filter and replace my spark plug to see if anything improves.

Has fuel quality degraded this poorly, or did I just get a couple crappy tanks of gas? It's my first winter with this bike, and I've never really ridden it with winter blend gas. I bought it last April when the weather was warm and the fuel was already in summer blend.

I have seen a slip in my car's economy too, but it's really hard to track since my driving habits are much more sporadic than my riding.

Anyone else (anyone who obsessively tracks fuel economy and range that is) noticed a significant loss of economy recently?
Zayretow

70' Vespa Sprint (2009 LML power)
74' Yamaha RD350 (pinger)
2008 Suzuki DRZ-400SM (thumper)

fredneckscoots
Posts: 327
Joined: Wed Mar 24, 2010 8:01 pm
Location: Fredneck, MD

Re: Perils of poor fuel quality...

Postby fredneckscoots » Tue Nov 20, 2012 4:18 pm

Just a hunch, but maybe this equation will help:

all that bullshit you just listed + your fat ass = lower mpg. :)
I break scooter parts

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Mikeh
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Joined: Wed Oct 04, 2006 2:36 pm

Re: Perils of poor fuel quality...

Postby Mikeh » Tue Nov 20, 2012 5:02 pm

My toyota echo still gets the same 39 to 40 mpg all the time. Even if there's no oil in the engine.

It's got 163,000 miles on it now and still gets the same mileage that it did when i bought it.

Maybe you have a fuel leak. or someone's stealing your gas.

dirtyhandslopez
Posts: 876
Joined: Thu May 01, 2008 1:12 am
Location: Richmond, VA.

Re: Perils of poor fuel quality...

Postby dirtyhandslopez » Wed Nov 21, 2012 10:34 am

If you are using the same gas station, maybe the pumps need to be re-calibrated. I believe they are checked once a year down here.
Praps one of your brakes are dragging everso slightly causing increase fuel consumption.
Worn out rings on the piston.
Heavy on the throttle a bit more than usual for a little while.
That's not going anywhere

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Zeets
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Joined: Thu Aug 19, 2010 6:42 pm
Location: Kensington (for now)

Re: Perils of poor fuel quality...

Postby Zeets » Wed Nov 21, 2012 10:48 am

Brakes are fine. I got 103 miles from 2.087 gal of gas on this tank, I'm assuming that I got a bad tank of fuel. Siphoning isn't really an option, I have a vacuum petcock, and a locked cap. I'm fairly sure no one was going to defeat the cap to steal .2 gal of gas. There's no fuel leak, it has about 6" of fuel line and the carb is drum tight, I'd notice a leak right away.

As far as your Echo is concerned, it's *probabaly* less sensitive to fuel quality than my DR-Z is. You Echo makes ~80hp from ~1.6l? I'm making ~50 hp from 397cc and have a 12.5:1 compression ratio, so if it's got a crappy tank of gas, I'd be more likely to notice it. It did feel slightly off pep wise the last tank or so, I noticed I was dogging it a little more to get up to merging speed.

Anywho, I put a fresh tank of 93 in it last night, we'll see how the economy goes this round.
Zayretow

70' Vespa Sprint (2009 LML power)
74' Yamaha RD350 (pinger)
2008 Suzuki DRZ-400SM (thumper)

dirtyhandslopez
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Joined: Thu May 01, 2008 1:12 am
Location: Richmond, VA.

Re: Perils of poor fuel quality...

Postby dirtyhandslopez » Wed Nov 21, 2012 11:07 am

Zeets wrote:I'm fairly sure no one was going to defeat the cap to steal .2 gal of gas.


I wouldn't be so sure...
I just had to sell a headset bottom to a man in NJ. His headset was snapped because gas thieves had decided they didn't want to use the fuel line and open the gas tap to drain gas, instead they turned the scooter upside down to drain the tank. Broke the headset in the process.
The man said it cost him nearly 1k to fix what had happened. He reckoned they got all of 2$ worth of gas :shock:
That's not going anywhere

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Zeets
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Joined: Thu Aug 19, 2010 6:42 pm
Location: Kensington (for now)

Re: Perils of poor fuel quality...

Postby Zeets » Wed Nov 21, 2012 11:46 am

dirtyhandslopez wrote:...His headset was snapped because gas thieves had decided they didn't want to use the fuel line and open the gas tap to drain gas, instead they turned the scooter upside down to drain the tank.


In all fairness, most thieves aren't smart enough, or willing to go through the work of taking a cowl off, cutting the fuel line and figuring out the fuel tap. Plus gas drains at about what? .25 gal per minute from an open fuel tap? I don't disagree that someone would try to defeat the locked cap on my bike to steal the gas, but it hasn't been tampered with, and I'd likely be out of gas after they're finished, not out of less than a half gallon. Plus we're not in a fuel shortage here in lower Montgomery county.

Maybe I'll go buy a drum of VP 105 octane and put it on my patio, after all, who doesn't love the smell of burnt race fuel, and when I get my Sprint together, I'll fill it up with the VP and put some Klotz 2T in there. It'll smell like I'm watching a super cross race in the 90's.
Zayretow

70' Vespa Sprint (2009 LML power)
74' Yamaha RD350 (pinger)
2008 Suzuki DRZ-400SM (thumper)

hurleybt
Posts: 406
Joined: Sun May 25, 2008 10:45 pm

Re: Perils of poor fuel quality...

Postby hurleybt » Fri Nov 23, 2012 11:13 am

If you want to catch people stealing gas, get a diesel, remove all the badges, leave the gas cap open and off. The thieves should be just around the corner where their gas car started giving them fits.


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