Help to describe issue with full throttle upshift on quick shifter

[DNCN]

I am having difficulty describing this issue to BMW but managed to borrow a camera for a couple of laps and capture it on track. I am looking to see if anyone else has had a similar issue and what the fault description and/or fix was.

Much easier to see on the road as you can repeat the problem on every upshift through from 3-6, BMW obviously won't be able to recreate any of that on a road test. Would also be easy to see on a dyno, but no facilities at the dealer.

The conditions are:
Wide open throttle
High in the rev range
Change up gear using quickshifter
Shifting 3rd-4th – occurs 75% of the time
Shifting 4th-5th – 100% of the time
Shifting 5th-6th – 100% of the time


The result is:
A hesitation. The revs drop as you shift to a higher gear, but there is no drive and the bike hesitates before the revs come back.
You can see in the video the reflection of my helmet, I am jolted forwards. Its quite severe when on the bike. The revs halt at about 11k in the video before rising again.
The video also shows speed dropping from 131 to 125 when the shift happens despite WOT.

Bike:
New 2024 S1000RR Sport (had 600 mile service last week)
Arrow Headers w/ Akrapovic Sports Exhaust
Everything else standard.


I have described this as “its is as if the bike is cutting ignition for longer than needed when shifting up on the quickshifter” can anyone confirm if that is that what it is doing?

Could it be a fuel mapping issue related to the arrow headers, but wouldn't that would mean any bike with OEM exhaust removed would have same issue?

thanks,

 

[Fraggle]

It's almost like you're noob shifting without a quickshifter

 

[TheGodfather]

Did you get it mapped when fitting the headers, presume a full system ? That is a must as far as I'm concerned.
Also have you tried re training the quick shifter to rule that out. It's in the manual and can be done on paddock stands.
I had the gear position sensor pack up on me once that was ok in the lower rev range but then acted like it was in limp mode.

Other than that I'm stumped.

 

[DNCN]

Not mapped, plan to take it to Crowe Perf but not yet spoken to them re booking it in. But now feel like this issue needs to be fixed before I took it anywhere for additional work.

Wasn't aware of the QS retrain, but have found the procedure - thanks, will try that tomorrow.

 

[MrSmooth]

I have a 2018 K46, had it since new, it was my first shift assist bike of any kind.

I admit that she doesn't like 'timid' upshifts with the foot, I had to learn to be really, really firm & positive with my shifter foot on the upshift. Otherwise the bike can hesitate on the upshift or even leave me in the same gear and try to have me over the handlebars.

I appreciate that you've just had it serviced, but I get similar issues of upshift 'hesitation' if the chain is too slack and again if the chain needs lubrication, so may I suggest that you check the chain slack again and lube the chain up again.

I also retrained my gearbox with the bike on the paddock stand just after I had it as brand new because it scared me too many times. Performing the gearbox retraining did make a difference and I was a bit angry that it hadn't been done during the PDI by the dealer.

Finally, I believe the shift detector rod has to be perfectly at 90 degrees to the shift request rod where you input the request with your foot. Worth a check that it remains at 90 degrees if you think that it might have been removed and replaced during the exhaust upgrade.

Good luck

 

[alex]

I had this on my 23 with the Alpha QS fitted.
I was going to reset adaptions and chain slack...but I got it mapped in the mean time and its disappeared.

 

[DNCN]

@MrSmooth - thanks, I wont dismiss any of those pointers and will go over over everything again. The bike is in race shift but, still, expectations are that it works.

@alex - that's reassuring, meaning it's likely a software based problem, assume it was the RS2E map you've written about. Why did you move to the Alpha QS, was it just for more control over settings etc for refinement?

 

[alex]

It allows for the fastest shifts and I am a magpie for kit.

Just arrived at Mugello, will let you know if it reoccurs

 

[DNCN]

BMW can't see the bike for another couple of weeks & I was very close to buying a GS-911 today to see if I could reset or reconfigure something. I had yet another check of chain, levers, QS and then went for a run up the road. However after playing around I figured out the cause, its wind against the clutch lever. If I push the clutch lever forwards the issue disappears.

Four previous RRs & I've never come across this before. Now I've changed what I am searching for, have obviously found a few mentions of this issue.

I've only ever run a brake brake protector, but will order a clutch lever protector and see if that's enough to deflect wind away along with adjusting the cable.

Hopefully all sorted and many good miles ahead.

https://s1000rrforum.co.uk/threads/upshift-issue.14032/#post-156038

 

[MrSmooth]

Doh, sorry, I did know about the loose clutch lever free play as there have been many others with the same issue on this forum too. Glad you found the fix.

 

[paradoc]

Doh, sorry, I did know about the loose clutch lever free play as there have been many others with the same issue on this forum too. Glad you found the fix.

ive got a very similar problem with my 23 shifts fine in low revs but once im over 8/9 revs i cant get any gears say in 3rd gear i cant get into any gear its like its stuck,ive tried using the clutch when this happens but that doesnt help still cant get any gears,unless i drop the revs to under 6000, ive checked the chain,clutch lever free play, qs rod angels,bmw cant find the problem cos they will not break the law

 

[alex]

It won't shift even with the clutch in?

Probably needs to be put on a dyno to diagnose. I would reset the adaptions if it was mine.

 

[paradoc]

cheers alex,i did the reset for the QS today but i havent been able to test it yet cos the weather is going to be shite for the next couple of days.im not sure if its related but DTC doesnt register at all on the dash, when i have been out riding in any mode the braking does show up

 

[alex]

Do you have any warning lights on the dash?

 

[paradoc]

No warning lights showing mate

 

[Kam187]

Gut says you’ll get a dash light if the DTC isn’t working.

Think you need to get it on a dyno with decent mechanic who can diagnose the problem as it happens with live data.