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Saturday, 4 May 2019

One for the Engineers or Techos amongst us

It's 11 years since I retired and a lot longer than that since I practised as a professional engineer.  However, once an engineer........  (accompanied by eye-rolling from my long-suffering wife), I can't just jump on a bike and ride the bloody thing.  Can't shut down the need to know a lot more about it - mostly stuff that is relatively unimportant and irrelevant to most of the human race and normal, sane people.  However, when we meet up with another rider who has similar inclinations, just try and shut us up!  Lifelong friendships have been forged with less of a bond.

This post is predominantly for Lee - friend, fellow IAM member and ENGINEER.  He posed some technical questions in the comments section of the previous post.  However, anyone without technical inclinations is most welcome to skip it.  And if you're a female, I am immune to eye-rolling and exasperated sighs as I've had 47 years of it from my beloved!

Bike forums are often known for opinion without facts to back them up.  My immediate mental response to that sort of comment is a grumpy "Where's the evidence?"  However, a recent forum post was about instrument errors on motorcycles.  By comparing speedo readings with those on my GPS, I knew that the speedo on my GSX-S 1000 was 8 km/hr fast at 100 km/hr.  I was immediately curious about the KTM so set off on the day before Good Friday to have a bit of fun and collect some data using the GPS as a reference point.

Bad Girl Lola at Kuaotunu, Coromandel Peninsula

The KTM has heaps of information on its TFT screen and even more info in a whole series of drop-down menus.  I was particularly interested in the accuracy of the speedo, odometer and fuel consumption.  Fuel consumption is influenced by all sorts of factors, not the least being your right wrist so I just rode how I normally do, switching between Street Mode and Sport Mode depending on road and traffic conditions.  I wasn't all that interested in absolute consumption, just what the instrumentation was telling me compared with fuel actually topped up at the end of the ride and distance covered according to the GPS.  Sad and nerdy person that I am, it was quite interesting.  I need to get out more.....

The main screen of the KTM 
(The range isn't really 720 km, it changes as soon as you get rolling)

These are the readings from a 170 km round trip on twisty roads.  Bike instrumentation compared against my Garmin GPS.

Speedometer:  Reads approximately 5% more than the GPS and looks pretty linear from a series of readings at various speeds.  At an indicated 190 km/hr, the GPS reads a little under 180 km/hr.  This particular reading is theoretical, you understand!

Trip Odometer:  Reads 6.6% more than the GPS.

Fuel consumption:  Bike instrumentation shows 8.9% more optimistic economy than the GPS distance divided by the actual fuel taken to top up the tank at the end of the ride.  True fuel consumption with a mix Street and Sport modes was 4.61 lt/100 km for the trip.  This looks about right for the 270-300 km that I expect from a full tank on an average journey without hammering but "making progress".

Just out of interest, compare this consumption with that of the GSX-S 1000.  On similar journeys, it used to drink 5.5 lt/100km.  On a trackday which Lee and I did in 2018, it was nearly double that consumption figure.  Lee's contention is that a combination of modern technology and Euro 5 emissions legislation is making modern engines more fuel efficient.  I don't think that there's much doubt about that and other factors such as power to weight ratio, gearing, drag coefficient all have a bearing on consumption.  Then there's external factors such as road conditions and your right wrist!

I'll repeat the experiment again on some longer future trip.

The other thing I recently tested was the headlight.  This is the first bike I've owned with an LED headlight.  Its angular or insectoidal-shape also made me wonder how good it was going to be in lighting up twisty roads out in the countryside with no ambient lighting.  We have nothing in NZ that's going to eat your face if you run into it, but collecting a sheep, cow or deer is going to sting a bit and spoil your day.

Based on a praying mantis or Alien from the movie?


 Full beam in daylight - bright!

Heading from Coromandel village to Whitianga township after dark is a good test as there's virtually no artificial lighting between them and lots of tight corners and elevation changes.  I'm delighted to report that forward illumination was really good and side illumination (road verges) was also good.  The latter was far better than I was expecting, given the headlight shape.  The following photos don't really do the headlight justice in reality but they do show that the important bits show up just fine.

Top of the Coromandel -Whangapoua hill.  Wet roads

Long Bay Road - good side illumination as well as distance

Naturally, lighting can always be improved with spotlights and the like.  However, I've done 5 NZ equivalents of the Iron Butt 1600 km in under 24 hour endurance rides on previous bikes.  There's around 11 or 12 hours of riding in the dark on mostly twisty unlit roads.  My yardstick is would I be happy riding in one of those events on the KTM?  The answer is yes - no problem at all.

If your eyes have glazed over after reading that lot, I apologise.  You can have a rest now as for part of May and June, Jennie and I will hopefully be having an excellent adventure in China and Hong Kong!

Fun in the sun


14 comments:

  1. Love this post. I, too, ask myself some of those same questions. It's just that, in my case, the response is, "That's an interesting question" and I do nothing to actually answer it. Which perhaps explains why I dropped out of engineering after 2 years! Enjoy China and Hong Kong - incredible places to visit, especially Hong Kong.

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  2. Thanks David! I'm good at procrastinating as well, but if anything really takes my interest, nothing else matters (according to someone who is not me). Thanks for the good wishes. Have travelled in Asia a fair bit but China is a first.

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  3. There may be a way to adjust the accuracy of the speedometer/odometer. On my truck, there is a tire diameter number within the ABS section. I would compare the GPS distance covered with the odometer and adjust the diameter accordingly (in 0.05” increments). Now they match within a few tenths over a 100 miles. And the speedometer is now right on as well. I suspect that any computer equipped vehicle these days has the same adjustments as my 14 year old truck…

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    1. Hi Richard,
      You're absolutely correct. In the case of most modern bikes, you can purchase a commercial device called a "Speedo Healer" which clips into your loom. Now that I know what my error is, I can mentally compensate. I would happily buy a healer but I'm terrified of cutting the wrong wires! I don't particularly trust local auto electricians either!

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  4. I'm a geek but not an engineer, I still enjoyed this.

    BTW: two stats from recent rides. I managed to get the speedo on the WR to read 32km/h while practically stationary the other day - beat that! And coming back across from Whanganui tonight the 1200 managed 4.8l/100km...

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  5. Thanks Andrew - Engineer, Techo, Geek are pretty much interchangeable according to some people :-). Good going on the WR! That's pretty good indeed on the 1200 - speedo or GPS? How do they compare? I'd imagine mine was pretty frugal tonight. Did some coaching in the Central Waikato and didn't bother to refuel. Short-shifting most of the way up the Thames coast road and sweating a bit. Reckon I was down to a litre in the tank!

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    1. That's off the gauges (normally optimistic like yours). Check latest blog for more economy geekery!

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    2. Impressive economy Andrew - similar to my GSX-S 1000 but with a bigger engine and more challenging conditions!

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  6. I belong to several motorcycle forums and there are always arguments regarding speedometer readings and GPS. I usually skip those discussions. lol

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    1. Agree - most forum debates end up as slanging matches!

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  7. Lovely post young Geoff, I found it a little lacking on the tech though. Try hard next time.
    Just kidding, I enjoy the technical aspects as I have an engineering type job as well. $1.80kmh you say, shame I say.

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    1. Sorry about the delay in replying Steve - only just discovered your post in the "awaiting approval" box - weird! I'll try very hard to be a sad bastard who needs to get out more next time :-) . I did say that the little squirt of speed was theoretical ;-)

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  8. Geoff

    Thanks for indulging my technical bent! Interesting stuff as always.

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    1. A pleasure Lee - we have to stick together on this sort of stuff :-)

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