Expected fuel consumption of the Transalp (1987-1999)
A common discussion between TAers. How do we "measure" it ?
As you can see in Specifications page, normal fuel consumption may vary over a very broad range. This is quite normal in all types of vehicles. However, it doesn't mind if we discuss the reasons.
Main factors affecting mileage of a well maintained TA (arranged by importance):
- Calm throttle operation - brakes usage (depend on driving manner and traffic conditions)
- Tank filling percentage (as a misleading factor that affects measurement itself)
- Passenger & payload
- Atmospheric pressure (engine efficiency is reduced at high altitudes because air has less oxygen)
- Higher windscreen, top case, other large accessories
- Ambient temperature (engine efficiency is slightly reduced at higher temperatures)
When calculating consumption, you must not use the theoretical capacities for main and reserve. It takes a very long time to completely fill the tank. Thus, in real world, total capacity is at least 1.5-2.5 lt. less than that specified by HONDA. Besides, reserve capacity is less than normal due to the approx. 1 lt. of unused fuel that is lying in the right bottom of the tank. Important trick: lie the bike to the left, in order to gain a few Kms, if you accidentally run out of fuel.
Pablo from Argentina post a relatively accurate and thorough method for measuring fuel
consumption:
1) Fully fill the tank, no matter its capacity (I think that a reliable filling mark would
be the lower end of the short tube that goes from the cap to the inside)
2) Set the trip meter to zero.
3) Run for some time. Any distance.
4) re-fill the tank to the same mark.
5) Divide the amount of fuel necessary to reach the same level (which can be precisely
read in the gas station pump display) by the mileage indicated by the trip meter. The
result of this operation is the exact fuel consumption.
The advantage of this method is its accuracy and what is more, you don't need to wait
until tank is empty so, you can do more checking in less time. Besides that, if you make a
200 km trip, then 100 km city drive until fuel runs out, the calculated consumption is an
average from different ways of riding. The same will occur if your trip is part on and
part off road. Averages are only useful for statistics. I suggest measuring (re filling
tank) after each different ride conditions. You may think this is tedious job but do it
just until you are able to construct a table or curve of consumption versus ride
condition.
Here in Greece, we usually switch to reserve at 180-220 Km. Many North-European or American drivers claim they switch at 270-300Km, achieving a mileage of 4.5-5 lt./100Km under normal driving conditions. Is this real, anyway (even considering the differences in filling procedure as well as the larger reserve capacity of some models)?
Update: In a travel of more than 300 Km, I achieved 307 Km before switching to reserve ! Conditions: original windscreen, 52lt top-case, no passenger. Keep in mind that I was driving in a VERY calm manner i.e. very constant throttle (95-100Km/h, only a few fast accelerations, rare brake use). Tank was not completely filled, so I calculated a mileage of 4.2 lt./100Km. It's impossible for me to drive this way again!
Conclusion: many people drive in such a way that fuel consumption can be much lower than that appearing in the usual
"aggressive" driving. I.e. they can achieve better than 5.5 Lt/100Km consumption instead of 6-7 Lt/100Km in the opposite case.
Additionally, driving is safer this way. However, no suggestions can be given here since the freedom of choice is an essential
parameter of the motorcycle driving.
At least, be careful...