Question New stock RC 390 backfiring

Kustard

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Hi everyone. I recently bought a 2017 RC 390 with only 700km on the odo. I was told it was totally stock besides some fork sliders and a tail tidy. However, I've started to notice the exhaust pops on deceleration. I've only owned one bike before so I'm not very mechanically savvy but I did a bit of research and it seems backfiring is often a result of bad tuning. I was wondering if it's by any chance normal for RC 390s and what I should do if it's not.
 

Nemesis13

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Congrats on getting an RC390. They are so much fun, Ive owned many bikes and this one is very addicting to ride.

I bought my 2018 RC390 with 49 miles, no decel pop. I looked at and test rode 4 RC390’s 17-20. Only one had decel pop, but it sounded like maybe they removed a baffle from the stock exhaust because it was a bit louder.

Maybe try a different fuel or it may need a valve adjustment. At 1000km first service they need to be checked and if needed adjusted.

just my two cents, hopefully someone with more experience and knowledge will chime in.
 

Kustard

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Thanks for the reply.
My last tank was the most premium kind available and didn't noticeably reduce the popping but the manual has a few others listed so I'll give them a shot. I was planning on doing the first service myself but might as well get the dealer to do it since the valves need to be checked like you mentioned.
 

Nemesis13

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I did my own first service which was really just an oil change, cleaning and lubing chain and giving it a good visual check. The dealership where previous owner bought the bike was going to charge $270 plus parts, which they said was only going to be an oil change and just checking over everything. They said rarely do they find it needs a valve adjustment.

Another KTM dealership really close to me wanted close to $700 and said they would do all the above plus a software update and if needed a valve adjustment they would do it. To me that was too vague and sounded like they were charging for a valve adjustment wether it needed it or not.

personally I was willing to pay $600 for first service if it included adjusting the valves for peace of mind. But it seemed to run fine so I did my own and used the money for a piggyback ECU with auto tune. Made a very noticeable improvement. Smoother throttle between 4-6k and improved low to midrange torque.

I probably am overthinking it. But before I was very apprehensive about buying the RC because of reliability issues I’ve read on the internet. It sounds like it was more the earlier models that had problems. I’m planning on just enjoying commuting and getting 55mpg, riding the twistier mountain road close to me where this bike shines

sorry I’m just blabbing, hopefully you figure out what’s causing backfire. Have fun!!
 

Kustard

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sorry I’m just blabbing, hopefully you figure out what’s causing backfire. Have fun!!
haha I appreciate all the second-hand experience I can get. I've already done the basics like changing the engine oil + filter and adjusting the chain so I'm hoping that would knock a good amount of the cost of the first service. I'm not mechanically savvy enough to check and adjust the valves myself though so I'm afraid I have to trust the dealer.
 
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