Here is the response I received back from Mccruise on April 1st. I will wait for a reply and post further updates.
Modern fuel injected vehicles have a fuel shut off function so that when the throttle is closed (released back to idle) if the engine is above a certain rpm (typically around 200rpm for cars and 2500 to 3500 on bikes) the fuel injection is turned off entirely, so the engine is not just at idle, it is turned off, like you had hit the ‘kill switch’.
When the rpm drops below that figure, the injection turns back on again, OR if the throttle is opened by the rider/driver, the injection is turned off.
In most cars, this is not particularly noticeable, as the engine braking effect is relatively small compared to the weight of the vehicle.
In bikes, if the engine has particularly strong engine braking, the effect can be quite significant. I have a 2009 DL650, and it is quite noticeable on my bike, but is fairly easy to rider around it, and the cruise generally copes pretty well too. On my bike to avoid this, I keep engine rpm below 3000, particularly when coasting into a slow corner, as it can be quite unsettling at first when the engine ‘turns on’ as the bike slows (engine speed drops below about 3000rpm). This feels like the bike is accelerating momentarily, when in reality it is just not decelerating as much.
The latest pollution standards have made this even more noticeable, and on the DL1000 it is very noticeable and can make low speed operation in low gears quite difficult at times, as the transition from throttle open to throttle closed is quite significant when the fuel injection turns off and back on. This sharp transition has made cruise control operation particularly difficult on this bike, partly because the layout of the bike has meant we have very long cables from the cruise control throttle servo to the bike’s throttle bodies. This gives the cable system significant ‘spring’ which has made precise throttle control for the cruise control more difficult. So result is so bad on this bike that we have decided not to release the 2018 DL1000 kit yet.
As a result I am re-visiting the DL1000 later next week with a view to moving the cruise control components to try to get much shorter and more direct cable runs to see if we can improve the performance of the cruise at low speeds.
It is already quite good at highway speeds, as under normal circumstances the throttle is not released all the way to idle unless it is going down a fairly steep hill.
We have one customer in the UK who basically fitted the 2016~17 DL1000 cruise to his 2018 model, and is not happy with the result, but is also not happy with the behaviour of the bike at town speeds, so he is considering fitting an aftermarket device that allow you to adjust many of the fuel injection parameters, one of which is to turn off the closed throttle fuel shut off. That way when the throttle is closed, the engine is running at idle, instead of being turned off completely, so the transition between closed throttle and cracking the throttle open should be much smoother.
If you are interested, this is the ECU mod they are referring to: woolichracing.co.uk/products/suzuki/dl1000-v-strom/2007/1003/2017-2018-suzuki-dl1000-v-srom-usb-d-v3-
I have had a look at this web site and there is some very interesting stuff in there that this device/mod allows ‘you’ to control. Don’t know how useful some of it is, but it’s there.
Anyway, hopefully in a week or so I will know if we have a product that works acceptably on the 2018 DL1000.