My understanding is that a significant amount of power is needed just to turn over the engine, and it increases with engine speed. Hence the "econ" button on earlier auto car gearboxes which got you into the high gears as early as possible. If the above effect happens, it means that the engine is running significantly less efficiently at the reduced engine speed, i.e. the power loss from poorer efficiency is greater than the power saving from lower engine speed, so you need more fuel. We're only talking about small changes in engine speed here (a few hundred revs), and the engine is operating in a "comfortable" range (just under 3K). It's amazing there's a noticeable difference.

Having said this, I have noticed that my bike (07RKC) feels better in 5th at 100-110k, and quite often I haven't realised I'm not in top.

Gonzo

If you are doing 110k's in 5th, and you will use more fuel by going into top, how does HD justify the 6 speed box?
If 55mph (88.5K's) is the top speed in the US, are they sat in 4th?

I still dont see the point if 85mph in a couple of very small southern US states is the speed limit and the rest of the country is 75 or less

us dyna owners dont seem to that opition .must be for special people .

i want answere y dont we?????

Just got back from Darwin, cruised in 6th gear at 110 in QLD and 120 ish in NT, bikes loaded, throttle roll on when passing (too lazy to drop back a gear) no pinging acceptable acceleration to pass roadtrains. Fuel consumption was between 5 and 7 litres per hundred, depending on the wind. Consumption went right up when sitting on 130.

I used about 10% more fuel than Phil. He has a fatboy with SERT, V&H and a high flow, I have a T/Max, suppertrap and high flow. But ive got mine running a bit richer than I proberly need.

One thing we did notice was that the fatboy with SERT speedo/trip meter caliberation was out by a few km every hundred.

Interesting thread, I'm a bit in line with gmeikle, I find my bike is happy enough to be changed into 6th at about 90 to 100kpm and doesn't feel like it's lugging at all. That is provided it's a flat road and no head wind. When I'm rolling off the throttle entering the city limits I change back down at about 80kph.
To say that 6th gear is not used until 120kph is a bit of a stretch for normal riding. But mind you I have waited until then when I'm in a bit of a hurry or want to blow the cobwebs out after puttering around town. You can feel what's happening without having a tacho, just ride to the conditions.

Noitartsurf. I notice that Tmax users don't at this stage get "KM to Empty" or a low fuel light on 08 models according to Tmax's website. Could it be the same with the V&H Fuelpak??

Incidentally, you can convert kilometers-per-litre to miles-per-gallon by multiplying by 2.8.

For example:

100km per 10 litres is the same as 28 mpg.

cheers

kiteman

 

 

I'm currently running in my Rocker (2-up). It feels like it's seriously "lugging" if I go to 6th at less than 100kph.

A PINK jerry-can!!!! Very cool styling!! Did you get a pic of that!!!??? hahahahah......he'd never live it down!!!!

A mate of mine wrecked his Panther. When it was rebuilt the workshop had pink paint so he told them to paint it pink. When he went to a big bike meet..... might have been Bathurst....... not sure..... he got abused by a very big Ducati rider who was very keen to break some bones for my mate's lack of taste with such a brilliant brand. My mate parked his bike in the tent and slept outside for the whole weekend!! 

 

 

noitartsurf, in reply to your query about the engine speed, here's a quick-and-dirty calc:

Measure your tyre diameter in mm. Mine's about 620mm (07 Road King Classic). If you can't get to your rear wheel easily, you can measure the radius from the axle centre to the outside of the tyre and then double it.

Divide 530516 by your wheel diameter. This gives your rear wheel rpm at 100km/hr. So, mine is 530516 divided by 620 = 856 rpm.

<< Note>> I posted this earlier today with the wrong calc above. I've edited it now and it's OK.

Next, look up your manual and find the gear ratio for top gear. Mine's 2.79. This is the ratio of the rpm of the engine to the rpm of the back wheel.

Now, multiply the rear wheel rpm by the gear ratio. Mine is 856 x 2.79 = 2388. That's the engine rpm at 100k.

You can do the same for the other gears. For example 5th for me gives 2806rpm, so if I change from 5th to top at 100k the engine revs drop by about 418 rpm. That's 2806 - 2388 = 418.

Gonzo.

I've got a 105 roadking clssic, I have noticed the fuel usage was better in 5th gear than 6th, and I've been changing into 6th gear at over 110. I've only done 2000ks so I thought it might get better when it loosens up a bit?

never use 6th.. I get about 17 km's per litre on average, always in the hills, and even up and done the freeway 5th seems perfect. 4th is my favourite....40 - 140 if need be..

HB07, note that your speedo is probably likely to be inaccurate. Mine over-reads at 110k by 8km/h, according to the speed detectors on the Hume at Albury. If yours is the same, the the rpm at 100km/h will be some 7% higher than your readings. Of course, this assumes the tach is accurate. In the end, it probably doesn't matter too much. The engine will still be revving slowly.

Gonzo