Low speed jerkiness - Honda CRF1000L Africa Twin Forum
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post #1 of 19 (permalink) Old 05-23-2019, 04:05 AM Thread Starter
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Low speed jerkiness

I have the 2018 ATAS manual
Lots of us have issues with low speed jerkiness, as though the bike cant make its mind up if it needs fuel or not. Has anyone taken their bike back to the dealer with this problem and can share their experience, good or bad.
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post #2 of 19 (permalink) Old 05-23-2019, 05:28 AM
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In which mode do you experience this?

I also have the manual ATAS. On TOUR and URBAN there is this what I suspect you refer to as "jerkiness" at low speeds. To me, it is absolutely justified since the throttle response on those modes is set to be quite sensitive and fast. So the issue may as well not be with the fuel management rather than how steadily we can twist the throttle at such sensitivity levels.

when commuting in the city, I usually use the GRAVEL mode and I find the bike perfectly responsive for a 1000cc machine.
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post #3 of 19 (permalink) Old 05-23-2019, 06:14 AM
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Originally Posted by BigKev View Post
I have the 2018 ATAS manual
Lots of us have issues with low speed jerkiness, as though the bike cant make its mind up if it needs fuel or not. Has anyone taken their bike back to the dealer with this problem and can share their experience, good or bad.

I have a 2017 manual and it went away after installing this simple and unexpensive thing !
http://www.dimsport.it/fr/rapidbike/easy/
If you worry about your mileage, don't be I find with my Ixil exhaust it might even improve a bit, setting it back to stock fueling does not
make any notable difference.


The bike is much more responsive and city riding feathering the clutch is no hassle anymore !

Last edited by Djairouks; 05-23-2019 at 06:17 AM.
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post #4 of 19 (permalink) Old 05-23-2019, 09:37 AM Thread Starter
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Originally Posted by Petros Galiatsis View Post
In which mode do you experience this?

I also have the manual ATAS. On TOUR and URBAN there is this what I suspect you refer to as "jerkiness" at low speeds. To me, it is absolutely justified since the throttle response on those modes is set to be quite sensitive and fast. So the issue may as well not be with the fuel management rather than how steadily we can twist the throttle at such sensitivity levels.

when commuting in the city, I usually use the GRAVEL mode and I find the bike perfectly responsive for a 1000cc machine.

I ride with either max engine power (1) or medium (2). In both the jerkiness prevails. I have not tried the least power setting 3 which I think applies to gravel mode. I ride in USER mode so that I can set power, engine braking and torque to my liking.
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post #5 of 19 (permalink) Old 05-23-2019, 09:37 AM
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Originally Posted by Djairouks View Post
I have a 2017 manual and it went away after installing this simple and unexpensive thing !
http://www.dimsport.it/fr/rapidbike/easy/
If you worry about your mileage, don't be I find with my Ixil exhaust it might even improve a bit, setting it back to stock fueling does not
make any notable difference.


The bike is much more responsive and city riding feathering the clutch is no hassle anymore !
This device works for some but not others. It didn;t work for me
, nor did a Hilltop remap. And neither one affected the fuel consumption at all which was surprising.
Some people have had success with Rapid Bike's Evo system which is much more complicated and takes some fitting, as does Powercommander's new module - available now for the 2018 onwards bikes. I'm waiting for their local dealer to tell me when he can fit one. (Expensive fix for the jerkiness though at £400 plus £70 per year extra on my insurance premium)
Mike
Mike
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post #6 of 19 (permalink) Old 05-23-2019, 09:59 AM
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Originally Posted by mike5100 View Post
This device works for some but not others. It didn;t work for me
, nor did a Hilltop remap. And neither one affected the fuel consumption at all which was surprising.
Some people have had success with Rapid Bike's Evo system which is much more complicated and takes some fitting, as does Powercommander's new module - available now for the 2018 onwards bikes. I'm waiting for their local dealer to tell me when he can fit one. (Expensive fix for the jerkiness though at £400 plus £70 per year extra on my insurance premium)
Mike
Mike

It's working but maybe if you keep the original exhaust you don't see the difference, because to me part of the jerkiness is the backpressure in the exhaust,
so having a more open exhaust will also improve it I think !
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post #7 of 19 (permalink) Old 05-24-2019, 06:36 AM
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Originally Posted by BigKev View Post
I ride with either max engine power (1) or medium (2). In both the jerkiness prevails. I have not tried the least power setting 3 which I think applies to gravel mode. I ride in USER mode so that I can set power, engine braking and torque to my liking.
The key point is that the power settings in the AT does NOT represent different power levels, but the amount of twist you need to apply to the throttle to get the power.

This means that in all modes, the engines delivers 95 BHP (nominal). But, the same amount of power, in Power setting 1 is delivered with less throttle twist vs the Power setting 2 and vs. the Power setting 3.

This eventually means that on power setting 3, you have better control of the fuelling. Try it and I think that you will see a vast improvement on the low speed jerkiness.
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post #8 of 19 (permalink) Old 05-24-2019, 07:05 AM
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Originally Posted by Petros Galiatsis View Post
The key point is that the power settings in the AT does NOT represent different power levels, but the amount of twist you need to apply to the throttle to get the power.

This means that in all modes, the engines delivers 95 BHP (nominal). But, the same amount of power, in Power setting 1 is delivered with less throttle twist vs the Power setting 2 and vs. the Power setting 3.

This eventually means that on power setting 3, you have better control of the fuelling. Try it and I think that you will see a vast improvement on the low speed jerkiness.
I would be interested to know if that is right (I had assumed that the fuel maps and ignition timing may well be changed in the 3 different power settings).
In any case there are two things going on IMHO. Part of the problem is caused by the throttle moving slightly as you hit bumps in the road and indeed this will be more apparent if you are in high power mode (and sport mode - ie a lower gear). Using a Kaoko throttle stabiliser can help with this issue.
But the other part of the problem is surely lean mixture at sub 2000rpm which all manufacturers have to do to meet Euro emmissions. This affects the jerkiness whether you are in high power or low power mode or sport or Drive or whatever gear you happen to be in. It can seem to go away by driving through town in say 3rd gear but that's because your engine revs are above the range where the manufacture has to keep it ultra lean. But if you like to 'tootle' as I do then IMHO the only solution is either a powercommander or the more sophisticated of the Rapid Bike Easy devices (the EVO not the EASY).
Mike
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post #9 of 19 (permalink) Old 05-25-2019, 10:07 AM Thread Starter
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So I have just got back from a run to try out the 'Engine power' settings. In USER mode its easy to change Engine Power settings without changing engine braking or torque, just come to a halt, leave engine running and change it, takes seconds
Setting 1 (most aggressive) - Throttle response is very quick and the bike is a joy to ride, especially when overtaking. The jerkiness is only noticeable when moving from overrun to the smallest throttle opening like you do in traffic. I presume that when the throttle is closed the fuelling is shut off as the engine revs are higher than idle due to the overrun. Its as though the throttle is too sensitive when making the transition from no fuelling to minimum fuelling. As soon as steady drive is reached there is no jerkiness.
Setting 3 (least aggressive) - Throttle response a lot softer for the first part. Same power appears to be available but occurs at a larger throttle opening. The jerkiness described above is reduced and barely noticeable
I am not sure how Honda have engineered the three power settings but I suspect (like others have said) that all that changes is how the engine management reads the throttle position. Put simply suppose you plotted throttle position against fuel input , setting 1 might look like a straight line at say 45 degrees. Settings 2 and 3 would be curves but would all end up at the same fuel input for full throttle.

So my conclusion is that I will leave the bike in setting 3, least aggressive. It means I have to twist my wrist a bit when I need a lot of power but that is a price worth paying to get a smoother low speed ride.
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post #10 of 19 (permalink) Old 05-25-2019, 11:40 AM
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Thank you Petros for the info and Kev for testing. I never gave it much thought, i.e., how it worked. The manly part of my simply wanted nothing to do with anything but the *most* power. I don't think my bike has ever been out of P1 for more than a few minutes.

But that makes a lot of sense... how it works. And might be just the thing for my slow-speed practice: trying to ride the bike at 2 mph in a straight line and then doing tight turns. But then again, there is very little throttle play most of the time if I'm on a flat surface: it's all clutch. But there are often the small inclines where I do have to add some throttle.

And I like slow shifting. I've talked about it before. Slow up-shifting, like I used to ride my bikes in the 80s. But the ATAS wants a quick up-shift. I've been taming her, but now wonder if P3 will help with that too!

Interesting. Very interesting.

Thanks again, Gary

...
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2018 Honda Africa Twin Adventure Sports - Manual.
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