Instrument accuracy (or lack of) - 2018 KTM 790 Duke Forum
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post #1 of 22 (permalink) Old 04-17-2019, 09:12 AM Thread Starter
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Instrument accuracy (or lack of)

Was planning a trip away on the 790 when I thought that with the 14 litre tank maybe I should check how accurate the instrument readings are, so with the aid of a GPS and refuelling at several different fuel stations in case the pumps were inaccurate I came up with some surprising findings.

A + reading means the instruments read higher than the true distance.

Speedometer ......... + 5%
Trip meter ............. + 2.5%
Fuel Range ........... + 5%
Fuel Consumption + 18% ***

Well the speedo error was as expected, +5% error is almost an industry standard these days, my last few cars had a +5% error and also my last 3 or 4 bikes

The trip error of + 2.5% is a little high compared to Jap bikes which are usually very accurate with their trip readings and seem to be around + 1.5% error.

Fuel consumption error of +18% was a real surprise, so my frugal fuel consumption figures of 29 km/l were all crap and a much more realistic figure of around 24 km/l fuel consumption were calculated.

The surprise figure here is the fuel range error of +5%, surprising because I would use use total fuel (14 litres) multiplied by fuel use (which is +18% high) to arrive at the fuel range but the fuel range is only +5% high so obviously KTM have deliberately set the fuel use figure high to make the motor appear very lean and frugal - which it isn't.


BTW my 790 is a July 2018 model with around 9,000 kms running Pirelli Angel GT tyres approx 30% worn and software version 0.17 (soon to be updated)
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post #2 of 22 (permalink) Old 04-17-2019, 04:37 PM
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Interesting figures! I haven't checked the speedo over a wide range against my GPS to see if it's linear but at the NZ legal open road speed limit of 100 km/hr, it pretty much matches your data, showing 105-106 km/hr. My GSX-S 1000 showed 108 km/hr. I haven't checked accuracy of the fuel consumption figures. From the "fuel remaining" readout, it indicates that I should be able to get close to 300 km (minus 5%!) But I'm not game to push my luck.

I'm heading out today for a couple of hours. Might try and collect some decent data.
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post #3 of 22 (permalink) Old 04-17-2019, 11:55 PM Thread Starter
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Thats interesting, up to 300 km range for you, I must be easier on the throttle because my instrument range is typically 340 - 350 kms indicated.
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post #4 of 22 (permalink) Old 04-18-2019, 12:50 AM
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Ok, here are my readings from a 170 km round trip this morning. Bike instrumentation compared against my Garmin GPS.

Speedometer: 5% more than GPS. Percentage looks pretty linear from readings either side of the open road speed limit.

Odometer/trip: 6.6% more than GPS. The route was pretty twisty and whether the lean angles (smaller effective diameter) for much of it had any bearing, I don't know.

Fuel consumption: Bike instrumentation shows 8.9% better fuel consumption than the GPS mileage divided by the actual fuel taken to top up the tank. Fuel consumption with a mix of Street and Sport mode riding was 4.61 km/100km. This looks about right for the 300km range I reckon I get on an average open road run without hammering it all the while.

I'm running NZ 95 octane fuel, the bike has covered ~2000 km and is on the OEM tyres.

I'll repeat the exercise in another 1000 km.
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post #5 of 22 (permalink) Old 04-18-2019, 07:32 AM Thread Starter
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Interesting, your fuel consumption is 8.9% error compared to my 18% error so looks like a fault with my bike, maybe a fuel flow sensor.
Will be getting a software update after Easter so will talk to the dealer.
Thanks for going out and checking my readings, much appreciated
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post #6 of 22 (permalink) Old 04-18-2019, 04:38 PM
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Quote:
Originally Posted by wozzamatta View Post
Interesting, your fuel consumption is 8.9% error compared to my 18% error so looks like a fault with my bike, maybe a fuel flow sensor.
Will be getting a software update after Easter so will talk to the dealer.
Thanks for going out and checking my readings, much appreciated
No worries - another local 790 owner who isn't a member of this forum said that he gets close to 300 km range when he's in cruise mode rather than hustling. Incidentally, my gauge never shows more than 300 km range even with the tank absolutely brimming.
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post #7 of 22 (permalink) Old 04-18-2019, 07:49 PM
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Same here, but its funny how it sometimes shows over 800km just after tanking/ before ridingXD. Wishful thinking
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post #8 of 22 (permalink) Old 04-22-2019, 03:37 AM Thread Starter
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Was a nice warm autumn night (20c) on Sat so thought I would go for the 790's first night ride since I bought it.
Stupid instruments said I was getting almost 35 kpl and my range was 380 kms doing 110 kph on the freeway - what the f**** how can I tour when my instruments are so obviously inaccurate.
Discovered something else, the headlight is an absolute joke on both high and low beam AFTER I realigned the beam. Pretty piss poor when you consider the price of this bike and the headlight being LED's, my $20 torch gives better output.

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post #9 of 22 (permalink) Old 04-22-2019, 04:50 AM
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Definitely sounds like you have a fuel reading issue. Mine doesn't go past 300 when full (after getting on the move).

Have only ridden in the dusk so far but the reports about the lights on YouTube have been quite complimentary. I must take it out after dark and check mine.
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post #10 of 22 (permalink) Old 04-22-2019, 06:44 AM
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Done a few Kms at night on mine now (not by choice) and have no complaints about the lights. I guess it's a matter of what you are used to.
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