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Discussion Starter · #1 ·
I saw a video 14T front sprocket made the 390 .28 seconds quicker to 60mph. Quick throttle seems to be a nice edition. Rapid bike ECU claims 44 rwhp and better low end with stock set up. Open air box and full exhaust systems add power .
Most people don't have a dyno handy. What I am curious about is how much quicker same rider. Like I hit 5.3 0 to 60 stock now 4.7 as an example.
 

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Best way to make the bike "quicker" practice practice practice....... It's a struggle to keep the front down on mine when I launch hard, even with stock gearing. If you are looking to drag race, since the front comes up so easy, this may not be the right bike for it..... if you just want to get to the next light quicker than you buddy, practice.
 

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Discussion Starter · #4 ·
Maybe I shouldn't have mentioned 0 to 60. Hard to measure roll on that's more of a seat of pants thing. I am pleasantly surprised at stock performance. I drive truck for a living no racing . I bought a 2016 for a good price. So I plan on tinkering with it . I really like how light it is and how well it handles . I'm interested in a ECU and pipe for heat reduction and longer life as much as power .if I have to choose between all hp gain and better mid range and torque vs more hp. I would take the midrange and torque.
 

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Reducing the weight of certain components would help to, like chain, sprockets, battery, passenger foot pegs removal etc

Also, the Yamaha my ride app measures the rate of acceleration in ft/s2 ;)
 

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Discussion Starter · #6 ·
Reducing the weight of certain components would help to, like chain, sprockets, battery, passenger foot pegs removal etc

Also, the Yamaha my ride app measures the rate of acceleration in ft/s2 ;)
Thanks it's surprisingly quick stock . I have no need for top speed but quick is fun. I'm changing the gearing first thinking ECU next . I'm hoping for even quicker and reliable. I'll try that app
 

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A German company (former KTM dealer) Pirate Racing, fitted an in-house made ram-air pipe with BMC cone filter, a PCV and some fine tuning getting an RC390 up to 52 BHP.
Unfortunately the discontinued their ram-air pipes that were made from a plastic and had a low resistance coating so now the only one I know of doing something similar is Chimera but out of aluminium and no coating and not really nicely done.
You can get these from 1Finger US and they offer a K&N cone air filter.
 

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The engine is already making a lot of HP for its displacement and the fact it's a single, I have a feeling that increasing it considerably would be at the cost of longevity and reliability. I'm not a tuner, I don't know this for sure, it's just my intuition that there's not a lot of headroom left in it.

This doesn't mean an ECU upgrade isn't worth it. I run a Coober in my 2019 and the difference is huge, but it's not about power gains, it's about smoothing out the jerkiness at low rpm, making the fueling more consistent. That particular ECU piggyback is not available for pre-2017 dukes afair.
 

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If riding with sense, warming the engine, shifting high up in the gears and using quality maintenance parts & oil (with the correct specs, nothing stands in the way of more BHP. Take 2 strokes for example.
 

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Discussion Starter · #10 ·
The rapid bike evo ecu claims better mid range and torque with an extra 4 hp in otherwise stock bike. A pipe might add 1 or 2 more hp. and reduce weight. Those sound like small gains but its 15 percent on a really light bike. Plus run cooler because it corrects the lean air fuel mix for government regulations. Chasing 50 hp is probably too expensive unless you go to a track.
 

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The rapid bike evo ecu claims better mid range and torque with an extra 4 hp in otherwise stock bike. A pipe might add 1 or 2 more hp. and reduce weight. Those sound like small gains but its 15 percent on a really light bike. Plus run cooler because it corrects the lean air fuel mix for government regulations. Chasing 50 hp is probably too expensive unless you go to a track.
On my 2016 I have installed a thin head gasket kit (stock blew out @ 6k miles, also had to shave the head due to a manufacturer defect), removed the top of the airbox (is two separate pieces) & installed a DNA race filter, PowerTRONIC piggyback ECU (for open loop & added rev limit) and FuelX controller (for closed loop), Gray Area KTM injector (reports from reputable engine builders say stock is maxed out above 9krpm, I am now at a 12k rev limit), and a LeoVince Exhaust. Bike is a beast now, and runs fairly smooth considering.... Stock they are putting out high 30's HP to the ground (lots of dyno proof of this online, all specs you see are giving crank hp @44), the way mine sits it is probably in the mid 45 range to the wheel. That is a huge difference over stock. Last I checked IIRC, I am shifting from 2nd to 3rd just under 60mph when I am beating on it :cool:

Also will want to change the coolant to something better if getting more from the bike, I switched to distilled water and Water Wetter after doing the head gasket. I have run Engine Ice in all my other LC bikes for years with great results, but needed something that day & none was available locally at the time.
 

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Discussion Starter · #13 ·
It seems like and this is pure speculation. A lightly moded 390 is similar performance wise to a Duke 620. The original hooligan just more refined. A little lighter about 5 less rwhp with a sixth gear . Obviously less torque and a quicker reving engine . My local dealer a DRZ 400 SM is 1700 more than a new 390. Those are cool bikes rarely called beginner bikes . I'm old enough I don't care what people think . I don't like the beginner bike label though. My only complaint on a extremely windy day it felt unsafe . It's always a trade off with motorcycles super light weight is great except on a windy day.
 

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Discussion Starter · #14 ·
Here's a post from MNNTHBX when they Dyno'd their 390's (with and without mods), shows real world Dyno #'s, more knowledge of the bike has been accumulated since then, but at least they give honest #'s. Also note the AFR on the sheet, looks like it could use some fuel in the low to midrange, LOL....

Finally got the MNNTHBX 390 to the dyno.[. Those numbers seem good to me peak horsepower is rarely used . Almost 9 hp gain with a flatter spread is a huge difference. No torque numbers but I'm sure it's similar. Definitely make a quicker and not really faster ( top end ).
 

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Maybe I shouldn't have mentioned 0 to 60. Hard to measure roll on that's more of a seat of pants thing. I am pleasantly surprised at stock performance. I drive truck for a living no racing . I bought a 2016 for a good price. So I plan on tinkering with it . I really like how light it is and how well it handles . I'm interested in a ECU and pipe for heat reduction and longer life as much as power .if I have to choose between all hp gain and better mid range and torque vs more hp. I would take the midrange and torque.
Greetings from Boston! I have a 2020 Duke. I installed the Coober ECU, de-restricted airbox cover and de-cat on mine and will never look back. The only other thing I plan on doing down the road is a slip-on.

Like mentioned above, not everyone has access to a dyno and it really wouldn't and doesn't make a difference to me. My bike is a frigging rocket. I'm not trying to come off the line every time fighting to keep the front wheel on the ground, it's not a drag bike and if anyone buys one of these with that intention they've missed the point.

With that, the Coober ECU works amazingly well. The stock 390 is exceptionally chonky off the clutch at 5 mph in traffic. It gets all chunky with too much fuel delivery. With the ECU all that goes away. You can take your hand off the throttle at 5 mph in first gear and the ECU figures out and corrects the fuel delivery so even in inclines it doesn't bog down, get chonky or stall. On the top end of things everything is smoothed out but far more responsive and aggressive when you grab a handful. I think my red-line/rev limiter bumped up 2500 RPM+ also.

The only other thing I did with this setup was to have the decat ceramic coated. I highly recommend spending 100 and having the decat ceramic coated. The radiant heat is reduced dramatically. Next winter I'm tearing the exhaust off and having it all ceramic coated. -it looks nice too, no discoloration at the header, no rust!
 
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