Hi, I have a strange issue with my BS6 KTM RC390, wherein the clutch appears to slip under heavy acceleration. When this happens i can feel the bike stop accelerating despite the engine spinning up and producing a distinct whine. The bike has only done 7600km. Matter of fact i have had the same issue on my earlier BS3 RC390 as well, only there the problem showed up after ~20k km, progressively getting worse until hard acceleration wasn't possible at all after ~40k km. Had to sell the bike. Changing the clutch plates didn't solve the issue.

Here's a clip from today's ride, a whine can be heard during corner exit and a loss in acceleration can be gleaned from the speedometer:



I don't misuse the clutch. Never done any hard launches from a stop, and i don't slip the clutch unnecessarily. Does anyone know what the issue might be?

Hmm, looks like there is a lot less activity on this forum since the last time i visited a few years back.
Anyway, i found a workaround: a more progressive throttle roll on, and making fewer shifts on the ride.

The YouTube link seems to be broken and hence couldn't gather datum. Clutch slipping on a brand new bike is extremely rare, but it isn't a factor that can't be ruled out either. Start off with your clutch free-play. Too little freeplay, meaning the clutch bike point way too down will eventually weaken the plates and reduce life drastically than a correctly set freeplay, that's one aspect of the diagnoses, albeit a crucial one at that. Make sure your clutch freeplay isn't messed up and the free-play and load correctly set, and see how it fares.

The catch to this conundrum is once a clutch starts slipping it's too late even with the freeplay adjusted to spec. Matter of fact, your clutch plates should be replaced and then the freeplay set accordingly.

Good luck.

Cheers!
VJ

Thanks for answering. Point taken: i'll need to get the clutch plates replaced, and also check whether the clutch cable is correctly adjusted (fully engaging the clutch).

Okay i finally figured out the problem with the clutch slip. It's not the bike. What was happening is that since i always cover the clutch with two finger, during hard acceleration out of a corner i was inadvertently lightly pulling on the clutch. This became prominent after the the mechanics adjusted the clutch in a recent bike service. All it takes is for the clutch to slip a few times at high load/RPM and it continues to slip for the remainder of the ride (a few minutes of cool down doesn't help). I haven't had to change the clutch plates after i figured this out. (Sorry I lost the video showing the slip, but here's the same without slip: https://youtu.be/VGrEa5_9mJA)