Kawasaki Vulcan Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
950 Posts
Discussion Starter #1 (Edited)
Many of us are running with Scootworks pulleys, some just the front or rear, others both. I have read, and heard folks say that their mileage is worse per the odometer. I must say that mine isn't very good either. :eek:

I have been thinking that since the front pulley changes the drive ratio by approximately 6% (5.9), which alters the speedometer by approximately 6% (making it accurate), shouldn't this also affect the odometer by about 6%? Are we not actually traveling 6% further than is stated by the odometer? Seems like we should be getting 8-9 actual miles more per fill-up than our odometer reads.

Of course, I could be wrong. Anybody have any data to support or disprove my little theory?
 

·
Premium Member
Joined
·
2,311 Posts
Many of us are running with Scootworks pulleys, some just the front or rear, others both. I have read, and heard folks say that their mileage is worse per the odometer. I must say that mine isn't very good either. :eek:

I have been thinking that since the front pulley changes the drive ratio by approximately 6% (5.9), which alters the speedometer by approximately 6% (making it accurate), shouldn't this also affect the odometer by about 6%? Are we not actually traveling 6% further than is stated by the odometer? Seems like we should be getting 8-9 actual miles more per fill-up than our odometer reads.

Of course, I could be wrong. Anybody have any data to support or disprove my little theory?
It's generally accepted that the speedometer is off by around 9.5%.
On my 900, the GPS shows 63.5 mph while the speedometer shows 70 mph.
I have not tried to determine if the odometer is off by the same percentage.
I believe that the speedometer is set high to limit the manufacturers liability over contested speeding tickets, plus the "nanny factor" to make you think you're going faster than you really are!
If you replace the front pulley with a Scootworks, you will be traveling farther and faster than you were before, assuming the same speedometer reading.
If you traveled 100 miles, got gas, and it took 2 gallons to fill up, then you got 50 MPG.
If after installing the new pulley, you traveled the same indicated 100 miles, and filled up with the same 2 gallons, you can assume that you actually traveled 5.9% farther than before.
So, 105.9 miles divided by 2 gallons would equal 52.95 MPG.
Theoretically, your actual gas mileage should increase with the overdrive pulley, but remember that it takes a certain horsepower to maintain a certain speed down the road. Your RPMs will be less, but to generate the same horsepower might require more throttle input, and negate any fuel mileage benefit.
There's just no free lunch here, and if you're replacing parts just to increase fuel milage, you might have a very long ride ahead before it pays off!
 

·
Registered
Joined
·
950 Posts
Discussion Starter #3 (Edited)
It's generally accepted that the speedometer is off by around 9.5%.
On my 900, the GPS shows 63.5 mph while the speedometer shows 70 mph.
I have not tried to determine if the odometer is off by the same percentage.
I believe that the speedometer is set high to limit the manufacturers liability over contested speeding tickets, plus the "nanny factor" to make you think you're going faster than you really are!
If you replace the front pulley with a Scootworks, you will be traveling farther and faster than you were before, assuming the same speedometer reading.
If you traveled 100 miles, got gas, and it took 2 gallons to fill up, then you got 50 MPG.
If after installing the new pulley, you traveled the same indicated 100 miles, and filled up with the same 2 gallons, you can assume that you actually traveled 5.9% farther than before.
So, 105.9 miles divided by 2 gallons would equal 52.95 MPG.
Theoretically, your actual gas mileage should increase with the overdrive pulley, but remember that it takes a certain horsepower to maintain a certain speed down the road. Your RPMs will be less, but to generate the same horsepower might require more throttle input, and negate any fuel mileage benefit.
There's just no free lunch here, and if you're replacing parts just to increase fuel milage, you might have a very long ride ahead before it pays off!
I am fairly certain you just said the same thing I did. Thanks for helping to verify my theory.
 

·
Registered
Joined
·
5 Posts
I'm not sure how it all works but i'm running a 200 tire and od rear pulley, and my mileage has stayed the same....right at 47.Half city and half 65 to 70.
 

·
Registered
Joined
·
711 Posts
I'm not sure how it all works but i'm running a 200 tire and od rear pulley, and my mileage has stayed the same....right at 47.Half city and half 65 to 70.
Have you upgraded exhaust, intake and fuel management?
if no then that's why you have manage to stay the same.
 

·
Registered
Joined
·
5 Posts
no...stock exhaust...just stage 2 debaffle, k&n air filter,moved the snorkel to the front on stock air box,and runs just a tad rich. But we aren't talking about that, its the pulley and tire that should change things.
 

·
Registered
Joined
·
742 Posts
well i am convinced that it "shows" worse, but we are actually getting better...

i have been out riding with this same guy who runs a stock harley... identical trips & fill ups... my mileage is always lower than his, which gives me a crappier MPG estimate... recently, he travelled 178 miles and mine said 163...

i am also convinced that our bikes get great mileage whether you have aftermarket parts on or not...
 

·
Premium Member
Joined
·
1,349 Posts
Hey Kendawg, don't know if this has anything to do with your thread, but I thought it was interesting...when we made our run recently through the Three Twisted Sisters, we all topped off with fuel that morning, all rode the same route, Whiting57 and I had our fuel lights come on at the same time, and when we filled up that night, we both took 4.3 gallons. Both 900, but I have the front od pulley and the 170 rear tire, he has the 200 rear tire and I think the stock pulley. We went by Poncho's trip-odometer and figured our mileage to be 46 I think, may have been 44, can't remember for sure. But I thought it was interesting with different changes to our bikes, we both got exactly the same fuel consumption going the same speeds and same distance over the same hills/curves.
 

·
Registered
Joined
·
950 Posts
Discussion Starter #9
Hey Kendawg, don't know if this has anything to do with your thread, but I thought it was interesting...when we made our run recently through the Three Twisted Sisters, we all topped off with fuel that morning, all rode the same route, Whiting57 and I had our fuel lights come on at the same time, and when we filled up that night, we both took 4.3 gallons. Both 900, but I have the front od pulley and the 170 rear tire, he has the 200 rear tire and I think the stock pulley. We went by Poncho's trip-odometer and figured our mileage to be 46 I think, may have been 44, can't remember for sure. But I thought it was interesting with different changes to our bikes, we both got exactly the same fuel consumption going the same speeds and same distance over the same hills/curves.
Zig, of course it does. What would have been interesting is if all the 900 riders would have compared odometer readings. What weekend is the Texas Kaw-Boy Oktoberfest? Perhaps a non-scientific observation is in order.:cool:
 

·
Premium Member
Joined
·
1,186 Posts
no...stock exhaust...just stage 2 debaffle, k&n air filter,moved the snorkel to the front on stock air box,and runs just a tad rich. But we aren't talking about that, its the pulley and tire that should change things.
The pulley and tire aren't the only things that affect fuel mileage though, that's why it is important. I have intake, exhaust, and power commander V. I get roughly 50 mpg when I stick around 65-70. I get 42-43 when I cruise at 75-80. I would get better with the pulley theoretically, but not guaranteed. It's an apples to oranges comparison. I can't get a realistic comparison if all t he numbers are based solely on stock bikes with a pulley and tire. That's apples to oranges. Now when someone has the big 3 and the pulley and tire, that's apples to apples.
 

·
Registered
Joined
·
696 Posts
Ken, have you tried running a measured mile or miles and/or comparing to a GPS?

I have a Scoot rear pulley and a Pirelli Night Dragon 200 rear tire. I haven't tried to figure out the reduction that I get with that combination. I also have a GPS and have tried to compare it to the speedo, but not the odometer. I don't know how accurate the GPS may be, but I do know that the mph of the speedo and the GPS don't match and it's not a linear mismatch. At the upper level speeds, the GPS and speedo are off a couple mph, but they are mostly in agreement at speeds lower than 40 mph. That's why I've not tried to figure out precisely what the combo does.

If you want, I can try to run a test on the freeway using the mile markers and compare to my GPS, speedo and odo, this weekend. Dunno how accurate the info would be though.
 

·
Premium Member
Joined
·
3,670 Posts
we all topped off with fuel that morning, all rode the same route, Whiting57 and I had our fuel lights come on at the same time, and when we filled up that night, we both took 4.3 gallons. Both 900, but I have the front od pulley and the 170 rear tire, he has the 200 rear tire and I think the stock pulley.
thats right.

We went by Poncho's trip-odometer and figured our mileage to be 46 I think, may have been 44
that was the problem ... with Tina on the back of his bike, the rear tire was not truly round and always flat on the bottom, hence the inaccurate mileage.:D

OUCH

I rememberer reading somewhere on here that the speedo and the odometer were on different hook ups and run independent of each other, i have nothing to substantiate that, it just rings a bell. ....

No Tina, not the dinner bell.
 
1 - 12 of 12 Posts
Top