Kangaroo Hops

[heli_madken]

Hi Everyone,


Not sure if this is a problem or not, I have had my 2014 wethead for a couple of months now and love it, now that the weather is getting a little drier and warmer I have started pushing the bike from a standstill now and then just to explore getting away relatively quickly.


I find it really hard to get the throttle/clutch coordination just right, if I dont the bike does some quite violent what I can only describe as kangaroo hops that can only be stopped by closing off the throttle then reapplying.


Is this just the nature of a hydraulic clutch, is it the traction control kicking in (dry road surface) or is it that I am just crap at getting off the line quickly and need more practice?


Never experienced it before on any bike I have owned, has anyone else experienced it?


Is it a matter of technique and getting used to the torque of the twin, I am finding that I have to let the clutch out relatively easily then use hard throttle once it is fully engaged, on my other bikes I would let the clutch slip a little, what techniques do others use?


Cheers

[David.]

I find it really hard to get the throttle/clutch coordination just right, if I dont the bike does some quite violent what I can only describe as kangaroo hops that can only be stopped by closing off the throttle then reapplying.

"If the front wheel lifts clear of the ground under severe acceleration, ASC reduces engine torque until the front wheel regains contact with the ground. Under these circumstances, BMW Motorrad recommends rolling the throttle slightly closed so as to restore stability with the least possible delay."

Is it the traction control kicking in.

Is the ASC warning light being displayed, does the same happen with the ASC switched off.

Never experienced it before on any bike I have owned.

Have any other bikes had traction control.

[heli_madken]

Thanks David,


I havent noticed the ASC light coming on, I will glance down next time it happens.


It is the first bike I have had ASC on, reading the BMW advice it does sound to me like traction control is cutting in but I wouldnt have thought I was being violent enough with the throttle to raise the front wheel


Ken

[michaelc2710]

Hi Ken


Check which setting you have the bike in, Rain, Road or Dynamic.
The traction control cut's in really early in rain mode and doesn't always flash ASC light.


If the road is dry and your confident in your skills try the bike in Dynamic and you will see the difference under hard acceleration.

[David.]

Reading the BMW advice it does sound to me like traction control is cutting in but I wouldnt have thought I was being violent enough with the throttle to raise the front wheel.

The front wheel doesn't necessarily need to be fully off the ground (Wheelie).

"The BMW Motorrad ASC system compares the speed of rotation of the front wheel and the rear wheel."

If the front end lifts sufficiently to reduce it's rotation or the rear spins up slightly, there could be enough differential in wheel rotation to cause the ASC to kick in.

[heli_madken]

Check which setting you have the bike in, Rain, Road or Dynamic.

This is in the dry in Road mode, bike is a 2014 SE, I dont seem to have a Dynamic mode?


I am beginning to think it is ASC kicking in but it is very harsh if that is the case

[gogs01]

This sounds more like an issue you might find on an air cooled, dry clutch bike.


The last of the air cooled bikes were registered in 2014 - are we definitely talking about a wethead ?

[heli_madken]

Thanks for the help everyone.


Yes its an LC, I guess one of the first being a 2014 plate.


If it is dry tomorrow I will try with ASC off.


I have the lever at its furthest setting as the clutch seems to engage very early in the travel of the lever, the bike has been fully serviced by BMW but perhaps she needs a fluid change.


Bit worried that no one else seems to be experiencing this, to begin with I thought it was just the nature of a hydraulic clutch, perhaps it needs some dealer input

[simbo]

Bit worried that no one else seems to be experiencing this, to begin with I thought it was just the nature of a hydraulic clutch, perhaps it needs some dealer input

I've experienced those symptoms before,  (different bike) turned out to be loose engine mount, could it be worth checking those?

[David.]

The bike has been fully serviced by BMW but perhaps she needs a fluid change.

Unlike brake fluid which is hygroscopic, the clutch fluid is oil based & therefore does not require routine changing.

[David.]

I have the lever at its furthest setting as the clutch seems to engage very early in the travel of the lever.

The clutch lever span adjustment is setting the engagement (bite) point either closer to, or further away from the grip. Whichever the rider finds most comfortable.

The hydraulic clutch itself is not adjustable, therefore, the clutch operation is not altered.

[David.]

Never experienced it before on any bike I have owned, has anyone else experienced it?

This MCN evaluation of a LC GS sounds similar, http://www.mcnews.com/mcn/model_eval/12 ... 1200GS.pdf

"The new 8-plate wet clutch is a big change. Unlike the automotive style dry clutches used on previous boxers, the wet clutch promised to be a big improvement as it should easily handle more abuse without overheating in demanding off-road conditions. And perhaps it could have been a purely positive experience, except that BMW chose to fit a centrifugal pressure plate assist to reduce lever effort and provide a back-torque limiting effect. While its lever effort is commendably light, such a design also changes engagement feel with rpm, becoming lightswitch sudden at higher revs. Attempting jackrabbit starts from lower revs, the clutch didn’t generate adequate grip, oddly grabbing and releasing for a hopping launch that didn’t inspire admiration. From high revs, its sudden action made wild wheelies too likely, so conservative launches were the only way to go, and we didn’t set any records as a result."

[heli_madken]

"Attempting jackrabbit starts from lower revs, the clutch didn’t generate adequate grip, oddly grabbing and releasing for a hopping launch that didn’t inspire admiration. From high revs, its sudden action made wild wheelies too likely, so conservative launches were the only way to go, and we didn’t set any records as a result."

Thanks David, That does sound eerily close to what I am experiencing and fits the bill for not showing up in more conservative starts, I think I am going to have to have a talk with the dealer.


I still find it strange that it isnt talked of more on forums I havent seen anyone else referring to it

[David.]

I still find it strange that it isnt talked of more on forums I havent seen anyone else referring to it.

The MCN link came from this thread in BMWMOA, https://forums.bmwmoa.org/showthread.ph ... ead-clutch

MCN R1200RT Evaluation, http://www.mcnews.com/mcn/model_eval/2014_06R1200RT.pdf

"Although the peculiarities of the new motor’s centrifugally assisted wet clutch—our only serious complaint on the GS models—aren’t as bothersome on the more sedate RT, it still causes concern occasionally, such as when you try to rev the engine and slip the clutch to make a quick start. But, rather than moving out smartly, the clutch (which uses soft springs for light effort) bounces in and out of engagement, killing your drive and jeopardizing your situation. Instead, you have to remember to engage the clutch fully before rolling on more power."

[heli_madken]

The comments on that post relating to bite point being very far out dont relate to my experience, full engagement I would say is 25mm maximum with the remainder of the travel of the lever doing nothing (approx 50% of the levers movement I would say)


I have adjusted to it but still occasionally fluff gear changes.


Although you stated their isnt any adjustment and I take your point about lever position adjustment according to this post on the GS Wethead there is some adjustment capability - https://forums.bmwmoa.org/showthread.ph ... pictorial), is it definitely not the case for an RT?


Not suggesting this will cure the hopping problem but at least it would move the bite point of the lever to something I am more used to