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Discussion Starter #1
I want to cure the low down jerkiness of my standard Duke 390. I am looking at two options based on functionality and price: Either the Booster Plug (cheapest option) or the Rapid Bike Easy (has a bit more adjustability). Has anyone here more real time on the road info of any of the two devices mentioned? Regards!
 

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Well l can tell you from experience that RBE cures the low speed running issues, as l have it on my Duke 390.
Just got back from a ride in fact.

I believe the booster plug works as well, they both work by fooling the bike ECU into making a slightly richer fuel mixture

Personally l prefer the way the RBE does it, which is by interrupting the signal from the exhaust lambda sensor and modifying it.

Maybe someone who has a BP fitted can relate their experience with it on their bike.
 

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Mine (2016) has a Booster Plug and it definitely improves things and gets rid of most of the surging at low speeds. Before I fitted it meeting slow traffic was a chore. If I was always in the city maybe I would be more critical.
No noticeable difference in fuel economy and it's been on the bike for 3000+ miles without any issues at all.
My decision was made easier by finding a used BP at half the new price so I'm very happy with the improvement vs. cost :)
 

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RBE on mine, can't speak of any other devices but before I had the Rapid Bike Easy the Duke was terrible in car parks, manoeuvring or just wanting to turn slowly with full balance and control. Whenever in first or second gear I'd have the clutch half pulled in to stop the engine jerking on and off power.
 

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Booster plug did wonders for my bike (2017)
cheap and really ease to install and remove, 5 min tops each time (I removed it each time the bike was in for service due to possible warranty issues)
 

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I take it then that the 2018 / 2019 390 will require another Booster Plug (upgraded??).
2017 and BACK have a different connection then the 2018 and FORWARD (2019)

I have a 2018 Duke. I bought this booster plug off someone on the forum - a week after I got my bike and didn't realise it wont fit my bike. So I bough the correct one for my 2018 and now have the PRE 2017 for sale.
 

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I have only had my 2018 Duke 390 for a week now and love it but I’ve already decided I can’t put up with the low revs problem and in some ways wish I had gone for the 790. I have already been looking at both of these boxes as well, are there any reputable dealers in the UK or do I have to get it shipped from outside the UK, the other thing is which is the best because if you look at the base option of both there is only £10 differences in the price.
Thanks in advance
 

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2017 and BACK have a different connection then the 2018 and FORWARD (2019)

I have a 2018 Duke. I bought this booster plug off someone on the forum - a week after I got my bike and didn't realise it wont fit my bike. So I bough the correct one for my 2018 and now have the PRE 2017 for sale.
Hi, that's not 100% correct, some 2017 have the upgraded sensors and will have to use the new Booster Plug.
I had this issue on my 2017 late model. The best way to determine if you have the old or new version on a 2017 bike is to look at the filter on the right hand side of the bike and see if you have an AIT sensor there. See installation instruction for a better explanation where the AIT is located
https://www.boosterplug.com/images/shopdownloadfiles/boosterplug_ installation_ktm_390_series.pdf
 

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Hi, that's not 100% correct, some 2017 have the upgraded sensors and will have to use the new Booster Plug.
I had this issue on my 2017 late model. The best way to determine if you have the old or new version on a 2017 bike is to look at the filter on the right hand side of the bike and see if you have an AIT sensor there. See installation instruction for a better explanation where the AIT is located
https://www.boosterplug.com/images/shopdownloadfiles/boosterplug_ installation_ktm_390_series.pdf
Thank you for this! I meant to say PRE 2017 = 2016 and BACK.

but thank you for the clarification!
 

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Discussion Starter #15
After much research I decided to go with the RBE. Thè price is nearly the same as the BP but the RBE has some fine tune adjustments the BP does not have. It also has a much longer loom which leaves more room for "hiding" the unit. Lastly it seems the RBE is more bang for your buck as the BP has very few electronic internal components and therefore may be a bit over priced for what you get..... Regards.
 

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imho (had both Gen 1 and gen 2 390's) - the reason for the jerkyness on Gen 2 bikes has a lot to go with the gearing - Lets face it at the traffic lights, you need to change up into 2nd almost immediatly and 3rd nearly as soon .....

so,

Change either the front sprocket to +1 or the rear sprocket to -3 ......

cost is a fraction of a piggy back box and improved my bike no end ......
 

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And as a result of changing your final drive ratio, you will still have an engine that runs too lean. The reason it runs ‘too lean’ is to satisfy the emission gods. In the days before EFI we would install a jet kit in the carburetor in order to eliminate an AFR that was too lean. Nowadays, with electronic fuel injection, we install a piggyback ECU such as RapidBike.
If increasing your final drive ratio satisfies your drivability issues then more power to you.
 
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Fitting the RBE transformed my 2109 Duke 390
Sadly the insurance didn’t agree and wouldn’t cover the bike at all with it fitted, so it’s currently disconnected.

The insurance is due in a month so l will find a company who is OK with it. After all the RBE doesn’t increase BHP it only makes the bike smoother at low speeds.

Although it’s hard to convince the insurance that a device called “Rapid Bike Easy” isn’t a tuning box and doesn’t make the bike any faster
 

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don't tell them it's fitted, they are not coming to inspect it,
how do these 'items' fit anyway, I've found my bike to be on off at low speed so I'm looking at a booster plug thing
 
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