Fuel runs results (VMax rear Diff)

[Seaking]

(short version of this in last paragraph to save you some reading...)

 

I finally managed to complete three highway runs to see how the fuel mileage stands after installing the VMax rear.. Interesting results as previously I thought my mileage sucked bad.. and now? "wow"..

 

2006 RSV Midnight, with K&N filters, RK pipes, recent oil change and valve check adjustments, new spark plugs, burning premium gas, E3 tires at 38/40 psi.

 

Travelling the whole test run at roughly 75 MPH (120 kph) on the speedo, turning 3,800 rpm. According to GPS this was actually 70 mph (110 kph) which is the legal speed limit on our twinned highways here. The entire highway route was done in 5th gear. Headwinds in the range of 15 mph, long inclines on the route..

 

Carrying a small 1.3 gallon (5 litres) gas can in the saddle bag, I ran the bike until reserve was reached. F countdown timer and reserve came on within a minute to 3 minutes of each other, depending on the incline and curve of the road. Reserve was switched over at around 170 to 175 miles (280 kilometers) at these speeds..

 

Now for the fun part, running the bike dry to finally find out how far can I go on reserve at highway speeds.. Bike shut down at around 222 miles (357 kilometers) on the ODO. So that gave me roughly 47 miles (75 kilometers) on reserve before running out of fuel at highway speeds.. Adding the 1.3 gallons to the tank, the bike ran with the valve off reserve for another 5 miles before having to switch it back to reserve to next gas station 8 miles down the road from where I had topped it up on the side of the road..

 

At the pumps, added 4.4 gallons (17 litres) of fuel.. add that to the 1.3 gallons already in the tank, less what I burned to travel that 8 miles.. 5.7 gallons.. Manual says the tank capacity is 5.9 gallons, so with what I burned to travel the 8 miles and the unusable portion of fuel, that comes close in numbers...? (something tells me this is off by some margin though...)

 

Next fuel run tests... back roads, 4th gear, 45-60 mph speed range to see how far the bike goes before reserve and running dry.. Should be interesting to say the least..

 

So the short version of this long story is that traveling at 75 mph on the speedo in 5th gear, the bike goes to reserve at roughly 175 miles with at least 40 miles on reserve after that.. which is a lot better than I had been getting at slower speeds on the back roads before putting the VMax rear diff on the bike.. Previous runs from gas station to gas station showed the bike doing anywhere from 43 to 45 MPG on the highway..

[darthandy]

That 5.9 gal. capacity would be in U.S. gal. In Canadian gal. it would be 5 gal. So, according to your figures, (222 miles to dry) that would be 44.4 miles per gal (CDN). That mileage figure sounds the same as what you say you were running with the stock rear end. That's pretty close to what I get with mine under those conditions, but I rarely run 5th gear unless it's a flat, level road and I'm holding a steady speed. Unless I'm missing something, it sounds like your mileage hasn't really changed much if at all. But then you now have much better acceleration and the capability to run 5th gear at lower speeds so it seems like you came out ahead ... a performance improvement with no gas mileage penalty. Sounds good to me!

 

Andy

[Seaking]

US Gallons indeed..

 

If those numbers seem the same as you're getting on your stock bike, that's awesome but for what ever reason, mine never got good mileage regardless to what I did to the bike or how well I maintain it.. That same run would have usually gotten me around 36 to 38 mpg instead of the 41-43 mpg (or better) I see now. Much of it I would think is the winds and terrain we have out here.. When ever I get west of here (NB or Maine and beyond) my mileage improves due to the relative flatness of the terrain in other areas..

 

Ever notice sometimes that certain speeds puts your bike in either too high a gear (lugging) or too low a gear (higher revs)? The rear diff swap gives you more flexibility.. Its hard to explain but running at 3800 rpm at various speeds with the vmax rear feels different than running that rev with the oem diff.. more pleasant, easier and comfortable...

 

Overall it makes for a better ride.. YMMV

[darthandy]

Yes, I know what you mean about that feeling of not being in the right gear sometimes. That's why I have also been thinking about going the Vmax route. Besides, there's nothing wrong with a little extra "get up and go", right? You are probably right about your environment having a detrimental effect on mileage, especially with the stock gearing. We visited Halifax some years ago when our daughter went to Dalhousie U. I can easily see where the stock gearing could result in poor fuel mileage and the Vmax change over would be a great idea. Lovely area there but I found that driving around "down town" in a full size van had me going over the curb on some right hand turns. Very narrow streets and it gets interesting with traffic. We really enjoyed the area though and want to go back again.

 

Andy

[Seaking]

Some of the most impressive scenic bike routes are located around here.. probably the highest rider population per capita in Canada.. Drop us a line if you come out this way to visit.. Drop me a line if you need to know more about the VMax rear diff..

 

Cheers

[cw1263]

Just checked my 06 RSV Midnight riding to work 62 miles round trip 60-70mph mostly 62-64mph 45.5 miles per gallon.

[darthandy]

Some of the most impressive scenic bike routes are located around here.. probably the highest rider population per capita in Canada.. Drop us a line if you come out this way to visit.. Drop me a line if you need to know more about the VMax rear diff..

 

Cheers

 

Thanks, I'll keep that in mind.

 

Andy

[IronMike]

On a bone stock 2008 with E3.36 Spark plugs and real Gas (Realgas.com) Im getting similar to what CW1263 is. The pipes look great and when I pulled the stock plugs they also looked great. I'm glad its getting this mileage as my Roadstar 1700 is a PIG. Im turning it into a spare, cruising bike.

 

More on topic, I either have the V max gearing, or I better stay where I am it it seems to be fine. And I am sure the former is not true, they guy who had the bike never even changed the coolant. So a new rear would have been out of the question.

 

Compared to the 1700 it is missing low end torque, but thats the beast. The PIG is missing neck snapping acceleration.

 

I suppose pulling a trailer the V max set up would be nice.

[MikeWa]

The v-max rear end will restore some of that missing low end torque. Depending on your wrist reflex it may do so without any loss of fuel mileage. But one never knows for sure until you try it.

 

Mike