Under hard acceleration, engine is spinning higher than wheel speed, why?

[mingo]

I owned a Gen 1 SuperTen and bought this Gen 2 in early spring of this year. It's been flawless but today upon entering the freeway, I opened the throttle with gusto and noticed that the engine revs up higher than the wheel speed and then the rpm drops from about 6000 to 4000 which then matches the wheel speed. I turned off traction control and can reproduce this at will. It's like the clutch is slipping but I don't abuse the clutch and doubt I've worn it out in 6000 km. This happens in 3rd or 4th gear under hard acceleration.

What's going on here :question:

 

[Bushyar15]

slipping clutch?

 

[Madhatter]

either back tire spinning or your clutch slipping, that would be my guess...

 

[yz454]

If the clutch is slipping the first thing bleed the system go from there .

 

[Don in Lodi]

6k? The dealership needs to be brought into it.

 

[cakeboy]

did your traction control kick in on a slippery surface ? ....has it dont it again since then ?

 

[Roge]

Traction control kicking in?

 

[mingo]

The first thing that came to mind was traction control, but the TCS light didn't flash like it would if activated and to be sure, I turned it of and was still able to do it.


This morning on my commute to work try as I might I couldn't get to slip. I opened the throttle wide in 3rd and 4th gears and it accelerated hard and the RPM"s matched the road speed. Yesterday, the RPM's would shoot up to 6000 and then drop down to 4000 as I was still under acceleration.


Bleeding the clutch?

 

[OldRider]

What oil are you running in it?

 

[mingo]

What oil are you running in it?

Whatever oil the dealer put in it at the 1000 km service, Yamalube as specified in the shop manual. I'm about to park the bike for the winter, so I"m going to change the oil and filter with whatever Yamalube is specified for this bike, gotta look it up.


I talked to my dealer and I'll bring it to him in the spring. It didn't do it on the way to work this morning, but when it did do it yesterday the engine was nice and hot.


Any other suggestions?


Bleeding the clutch is the easy step, step 2 might be to remove the clutch cover and have a look at the clutch plates.

 

[fredz43]

Have you recently changed the clutch lever? I ask because a couple years ago I replaced the levers on my 2012 with aftermarket ones and when installing the clutch lever, I didn't get the plunger inserted correctly in the recess in the clutch lever, so it was being pushed in slightly when in the out position. I didn't notice any problem and all seemed fine until I got out of town and accelerated in the higher gears and the clutch immediately started slipping. I stopped and was able to remove and reinstall the aftermarket lever properly with the tools on board and all was well.

If you haven't changed levers, would it be possible for some crud to get in there and have the same effect?

 

[mingo]

Yes, I did replace the cheap OEM levers the first day I had the bike.. I did check the clutch lever as you suggested and the pin is seated properly. Thanks for the suggestion.


I'll be putting away the bike for the winter soon, so I won't be able to do any more checks.. I'll take it to the dealer in the spring for a check up.