Re: KTM RC 390 Ownership Experience

Thanks for the suggestions, on the tires, its 29 in the front and 31 in the rear usually. But I dont think that's a main reason, SVC people near my house are of not much use, they outright tell that's how the bike is, well I'm not expecting some 30kmpl but at least around 18kmpl in city.

Re: KTM RC 390 Ownership Experience

Hey Guys, i hope you are having a great week and looking forward to an even better ride on the weekend.

My 2018 RC390 which used to easily do 175-176 on the speedo sometime back is now getting up to a maximum of 173, at which point the ECU cuts fueling. Has the ECU been updated recently to limit top speed to 173? I don't think it's an internal engine issue because the engine is still revving to redline, but what I am thinking possibly is that the ECU was updated and the redline was brought down a skosh.

The other thing coming to mind is possibly the speedo error increasing so now it underrates the speed? i think the speed sensor is in the gearbox with these things, right? What do you think could be the answer?

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So after writing my last post, i ended up doing more investigation on the issue.

I put the bike on the paddock to check what the top speed of the bike is with a free rear wheel. The engine is redlining at 172! Gearing is all stock.

This is odd because the 390s are geared to go to 178 on stock gearing. Any one here with any input as to what could the issue be? I don't feel a lack of power and the engine is redlining at 173 even while riding, but it's just that it's redlining earlier than before.

Re: KTM RC 390 Ownership Experience

172 you did while bike was on paddock stand?

Re: KTM RC 390 Ownership Experience

Yes . It can be unsafe but It was hitting top speed for 2-3 seconds at most and not more. Just some of the dangers that we riders sign up for in our quest to maintain our bikes perfectly.

Re: KTM RC 390 Ownership Experience

Interesting. What was the earlier redline you observed, and what's the engine redlining at now?

Cheers!
VJ

Re: KTM RC 390 Ownership Experience

I am just as clueless as you. As I mentioned, the redline being reduced is just speculation because that explains the top speed coming down. Along with the other possible explanation, speedo error.

Besides, that's legit the most difficult question ever. The bar graph tach on this thing is smaller than an ant. I bet I couldn't tell you even with a microscope.

Nevertheless, let me get back to you with how much this thing is spinning currently.

Re: KTM RC 390 Ownership Experience

there is a speedo sensor on the front (fixed on the fork).
and maybe one on the rear?? because its an abs model.. am not sure about this part.
but it definitely doesn't have one in the gearbox like the cbr250 does.

i wouldn't be too worried with the speeds you are hitting, and there are no ecu updates as such that affect the rev limiter thus far. the rev limiter is still at 10500rpm and there will be a small variation in top speed depending on conditions.

Re: KTM RC 390 Ownership Experience

I think what you are referring to are wheel speed sensors? i think they just sense wheel rotation differential (one wheel moving faster than the other) to sense wheel lock amd activate ABS. I could be wrong though, please feel free to correct.

It definitely has an internal speed sensor though because the bike was indicating speed while on the paddock.

Re: KTM RC 390 Ownership Experience

yes, i got confused.
the rc390 has an abs speed sensor on both wheels (the tiny black thingy near the abs ring).. and these collect the speed readings.
there is no internal speed sensor.
what model year is yours ?

the earlier 200's (non abs) have a speed sensor located on the front fork .. i've had it replaced once on my D200. i got it confused with this.

Re: KTM RC 390 Ownership Experience

My plain-jane understanding of the 2-wheeler ABS system is that it needs atleast 2 speed sensors - one that shows road speed (reference for the ABS computer) and another from/on the wheel ABS should act. Post ABS introduction, Bajaj has removed the "normal" worm-gear speed sensor from all vehicles (eg: NS/RS). So my guess is that the rear wheel speed sensor supplies the normal speed indication on the speedo/for ABS reference and also might act for rear wheel lift-off (RLP). It is easy to put a pulse-r ring on the rear wheel than a worm gear. That's why it was indicating speed even on paddock. I don't remember seeing/reading about an internal speed sensor on the NS/RS/KTMs. Actually I wonder if it's different to mount the sensor on the rear wheel vs. countershaft because they are anyway connected.

Re: KTM RC 390 Ownership Experience

From what I can say, and from my experience of the Duke, the Duke doesn't have a transmission speed sensor like the CBR or other bikes. The bike primarily, takes the speed values from the front wheel and not from the rear wheel. Even with the paddock on, for even the 2019 ones the speed is taken from the front wheel only and not from the rear.

Cheers!
VJ

Re: KTM RC 390 Ownership Experience

So if put on a paddock, it displays the rear wheel speed ignoring the front? So, Rear is the secondary input or only there for lift off protection?

Re: KTM RC 390 Ownership Experience

Top speed performance is irrelevant. If your bike is showing signs of losing performance like power drop or heat increase or odd, noises, best to check engine . Top speed depends on the tyre conditions, road conditions,uphill or down , bike oil condition.

Re: KTM RC 390 Ownership Experience

the rear abs speed sensor is there as part of the abs mechanism. i dont think the rc has rlp

even without abs (like the older model ktm 200's) the ktm's never had the worm gear setup.. it was a sensor on the front (attached to the fork leg with the wire going up, to inside the headlight assy area). iirc it picks up the readings off the rotor bolts as they spin. i've had this sensor replaced once when the speeds were showing up erratically.

in case you put the bike (390) on a paddock and test, i guess the speed from rear wheel is displayed on the console (because the front is stationary and it also doesn't have any sensor on the engine side like a cbr250r does.)

Re: KTM RC 390 Ownership Experience

Yes, I got it doubly wrong - even the non-ABS classic Pulsars/NS-RS had only a magnetic sensor.

So your model doesn't have a pulser ring. That's interesting - it explains why the rotor bolts are bulging and normal hex instead of the usual Allen bolts they use there.