Surprising increase in mileage

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bdento59
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Surprising increase in mileage

Post by bdento59 »

Hi folks, long time no talkie. Also, I'm sorry I missed everyone at Mid-Ohio VMD once again this summer. As hard as I try to get there every year, I'm averaging once every three years lately.

Anywho, I just got the '80 SS back on the road this July for the first time in two years and something curious is happeneing with my mileage. It seems to have gone up by an incredible amount, i.e. From 32>38 mpg. I'm wondering how that could be? While off the road, I did a valve adjust, plugs, wires, Dyna coils, replaced the K&N air filter with a paper one and shimmed the carb needles by 0.040". I also replaced the rear tire, had the rear rotor blanchard ground and cross drilled and rebuilt the rear brake system, but I don't suspect the latter group had anythg to do with the mileage increase.

My logical mind says that the changes I made "may have" contributed to a minor change in mileage, but a 19% increase? Methinks not... What say ye, and as always, TIA!
Bill Denton
Yardley, PA
wkdenton@verizon.net
Lazarus Cycleworks, LLC
We Breathe New Life into Old Bikes

Rick Pope
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Re: Surprising increase in mileage

Post by Rick Pope »

Hey Bill, it has been a while.

The "tune up' would contribute some, but likely not that much. But, did you by chance switch to a taller profile tire, thereby raising your effective gearing?

Or, have we gotten older and just don't play quite as hard? :o
Rick Pope
Either garage is too small or we have too many bikes. Or Momma's car needs to go outside.

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bdento59
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Re: Surprising increase in mileage

Post by bdento59 »

Hi there Rick,

I did change the tire, but not the profile... :<(
Bill Denton
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Lazarus Cycleworks, LLC
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Re: Surprising increase in mileage

Post by Larry Zimmer »

Hmmm. Wonder why the 32 initially?? Not that much difference between an 80 and an 82. My 82 consistently gets 40. Stock. Makes me wonder if the K&N was 'filtering' a bit much. The only other thing that I can think of quickly would be that the rear brake rotor was doing some dragging that was eliminated by your work there. Unless one of the valves was significantly mis-adjusted. (Somehow I doubt that.)
Larry Zimmer
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Re: Surprising increase in mileage

Post by EMS »

bdento59 wrote: , I did a valve adjust, plugs, wires, Dyna coils, replaced the K&N air filter with a paper one and shimmed the carb needles by 0.040". I also replaced the rear tire, !
That is a lot of work an almost everything would help to increase the mileage. Don't discount the effect of a new tire. Lower rolling resistance and (higher?) air pressure will make a difference.

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Re: Surprising increase in mileage

Post by Rick Pope »

Personally, I think Bill's getting older, like the rest of us. :o
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Either garage is too small or we have too many bikes. Or Momma's car needs to go outside.

steve murdoch icoa #5322
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Re: Surprising increase in mileage

Post by steve murdoch icoa #5322 »

Hi ya, Bill.
Knowing how poorly a CBX can run with just an improper air filter, i am not surprised by the increased gas mileage after ALL your maintenance.

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