KTM Duke 390 pro-race shorty or coffmans shorty
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Coffman's KTM Duke 390 Coffman Shorty Slip On Muffler Exhaust 2021-2022 would the Coffman still be to short? I know the pro-race shorty is extremely short
I have the Pro Race, it's just a hollow piece of metal that slip-ons, nothing special for noise differences, just louder. Very short so you wouldn't need an exhaust hanger, compared to the Coffman's which does. Coffman's comes with a baffle insert, Pro Race does not, but can be ordered in titanium or black or stainless, and added mesh to it or not.
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According to the hundreds of dyno runs, all short dampers lose power compared to full long cans.
Okay thankyou for this information, Any recommendations on a slip on that isn't going to cost me more then $600aud
Or in saying that would I still lose power if I added the shorty and a ecu piggyback to tune it for that specific exhaust? Thankyou for your information I'm new to the duke world only owned bigger bikes in the past and never had these problems
".....Bigger bikes", or older bikes; that were not fuel injected - and likely not as constricted up / bound by emission's laws as some (THIS !!!) 'modern' motorcycle(s) ?
In saying that - i agree with you. The 390 is quite a fickle beast fuelling-wise. And even compared to other modern bikes i've owned - does run particularly lean as standard. So any opening up / work on the breathing side and / or exhaust is likely to lean it up even more........
Good Luck
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According to this tuner, an electronic aid won't improve a shorties performance over a large volume can.
He has good results with Leo Vince silencers.
I think you can also have a look at the MIVV products.
What is the objective of changing the exhaust?
He has good results with Leo Vince silencers.
I think you can also have a look at the MIVV products.
What is the objective of changing the exhaust?
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2,667 Posts
An often heard generalisation.
Yes the Dukes are on the lean side IN THE CLOSED LOOP determined by the O2/Lambda sensor.
Outside the closed loop they run slightly rich.
This is why a B-plug isn't the best solution as, although it aids in the closed loop sessions it also makes the open loop even richer.
In the long run the excess fuel washed away the lubrication on the cylinder wall and the bike performs less due to a too rich mixture at higher revs (open loop).
Yes the Dukes are on the lean side IN THE CLOSED LOOP determined by the O2/Lambda sensor.
Outside the closed loop they run slightly rich.
This is why a B-plug isn't the best solution as, although it aids in the closed loop sessions it also makes the open loop even richer.
In the long run the excess fuel washed away the lubrication on the cylinder wall and the bike performs less due to a too rich mixture at higher revs (open loop).
".....Bigger bikes", or older bikes; that were not fuel injected - and likely not as constricted up / bound by emission's laws as some (THIS !!!) 'modern' motorcycle(s) ?
In saying that - i agree with you. The 390 is quite a fickle beast fuelling-wise. And even compared to other modern bikes i've owned - does run particularly lean as standard. So any opening up / work on the breathing side and / or exhaust is likely to lean it up even more........
Good Luck
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