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Do you wheelie your viffer?


bighawk

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2 hours ago, bighawk said:

 

Yeah, I'm sure that TC isn't wheelie control but it must effect power wheelies and even clutch wheelies.  If the computer is sensing disturbance to the power transfer and a slippage from the clutch, it makes sense for it to shut down the bike.  I'd have to disagree that TC has nothing to do with wheelie control - the question is, how much does it have to do with it?  One way to find out :P

 

TC has nothing to do with clutch slippage, but you are otherwise right.

 

First and foremost, it detects speed differential between front and rear tyre ABS sensors. If rear tyre speed is more than front, cut engine power (some TC systems allow a gradual reduction - however I suspect that as the VFR doesn't have fly by wire - it simply shuts the fuel intake down - which is why some people find it a bit too aggresive).

 

Personally in 6000km I have only knowingly encountered TC once in absolutely torrential conditions.

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7 minutes ago, adprom said:

 

TC has nothing to do with clutch slippage, but you are otherwise right.

 

First and foremost, it detects speed differential between front and rear tyre ABS sensors. If rear tyre speed is more than front, cut engine power (some TC systems allow a gradual reduction - however I suspect that as the VFR doesn't have fly by wire - it simply shuts the fuel intake down - which is why some people find it a bit too aggresive).

 

It feels and sounds a bit like hitting a rev limiter and no, no fly-by-wire on the VFRs.

 

The problem for me at least is it doesn't seem to dynamically disengage.

 

MotoGP grade, it ain't.

 

And in my experience it tends to be an impediment to playful antics.

 

 

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13 minutes ago, Rectaltronics said:

The problem for me at least is it doesn't seem to dynamically disengage.

 

Well without fly by wire.... you can't really dynamically disengage. All you can do is skip fuel injection cycles, deliberately misfire the spark plugs etc... 

 

I think you'll find all the bikes with a more advanced system have fly by wire.

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2 minutes ago, adprom said:

 

Well without fly by wire.... you can't really dynamically disengage. All you can do is skip fuel injection cycles, deliberately misfire the spark plugs etc... 

 

I think you'll find all the bikes with a more advanced system have fly by wire.

 

Why should lack of fly-by-wire prohibit disengagement of the TC when wheel rotation speeds match again?  If the computer can screw with fueling and ignition then it can un-screw with the fueling and ignition.

 

It's just mediocre engineering.

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9 minutes ago, Rectaltronics said:

 

Why should lack of fly-by-wire prohibit disengagement of the TC when wheel rotation speeds match again?  If the computer can screw with fueling and ignition then it can un-screw with the fueling and ignition.

 

It's just mediocre engineering.

 

Because using the method of skipping ignition sparks or shutting fuel down is an on or off affair.

 

Fly by wire allows the throttle to be dialled back by the computer gradually and still maintain thrust - but in a granular matter.

 

Using the first method - you can't just wind a spark down to 50% or 30% to hold on the edge of traction like you can with the BMWs.

 

So it won't prevent re-engagement - but it just can't be anywhere near as smooth as a fly by wire system. As such, as you said - it is like hitting a rev limiter. It's not mediocre engineering - it's a technical limitation.

 

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1 minute ago, adprom said:

 

Because using the method of skipping ignition sparks or shutting fuel down is an on or off affair.

 

Fly by wire allows the throttle to be dialled back by the computer gradually and still maintain thrust - but in a granular matter.

 

Using the first method - you can't just wind a spark down to 50% or 30% to hold on the edge of traction like you can with the BMWs.

 

So it won't prevent re-engagement - but it just can't be anywhere near as smooth as a fly by wire system. As such, as you said - it is like hitting a rev limiter. It's not mediocre engineering - it's a technical limitation.

 

 

If wheel speeds match again then there's no reason to not disengage.

 

 

 

 

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18 minutes ago, Rectaltronics said:

If wheel speeds match again then there's no reason to not disengage.

 

I don't get your point? You can't simply apply that rule to the system or you are going to end up with an underdamped system that will oscillate - it will gain traction, lose traction, gain, lose etc etc.

 

With fly by wire - you wind the throttle back and then gradually reapply using a properly damped algorithm to prevent any yoyo effects.

 

This isn't that simple when you only have fuel pump and ignition system as factors to play with. I suspect it works the same as the quick shifter - interrupts the ignition spark.

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Let me try this another way...

 

Braking isn't "by wire."


The ABS disengages just fine when traction returns.

 

It manages to do that without oscillations.

 

OK?

 

The TC even uses the same sensors as the ABS!

 

There's nothing gradual or granular about being forced to close the throttle to get the damn TC to disengage, ya' know.

 

Ignition and fueling is already almost entirely under computer control already.

 

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21 minutes ago, Rectaltronics said:

Let me try this another way...

 

Braking isn't "by wire."


The ABS disengages just fine when traction returns.

 

It manages to do that without oscillations.

 

OK?

 

The TC even uses the same sensors as the ABS!

 

There's nothing gradual or granular about being forced to close the throttle to get the damn TC to disengage, ya' know.

 

Ignition and fueling is already almost entirely under computer control already.

 

 

ABS is a different kettle of fish. It's trying to keep something rotating - so it is simply releasing the wheel and then re-engaging the brakes. They key here - is that it can do it as fast as the computer/hydraulic mechanics will allow. Modern systems are up to 20 times a second I believe (early ones were 5 to 8). Under braking you can also tolerate this relocking up scenario - so you literally do get an oscillation - thats how ABS works. Continually unlocking the brakes.

 

Traction control - you skip ignition when under 3/4 throttle - wheel speed resumes and instantly re-engage the system - you are going to cause the user to get hit with a sudden jolt - potentially causing a high side and loss of traction again. ABS will come to a natural end once the bike inevitibly stops - using the same methodology with TC won't work because there won't be a natural dampening effect (i.e. eventually stopping).

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LOL, the TC will come to a natural end once the vehicle behind slams into the bike as the rider wonders WTF happened to his acceleration.

 

The same inertia that applies to the wheel(s) for ABS applies to it for TC.

 

The only difference is that one modulates braking and the other modulates ignition.

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Let's try and clear this up for you guys...

 

I have experienced TC many times, and verified when I first got the bike that it WILL prevent a wheelie.

The way it functions is to completely cut all power (not sure which way, but I suspect fuel cut).  It IS abrupt and stays off for too long...feels like more than a full second, but never tried to time it.  It does come back somewhat abruptly, because your first instinct when you feel power cut is to give it more throttle.  It's not quite an "on/off" engagement, but it comes back pretty quick...No chance of a high-side.  Our TC system is about as basic as they come.  It uses the ABS rings to detect difference in wheel speed between front and rear.  For that matter, our ABS is quite basic too, but seems to function quite well.

 

I don't understand how people ride for thousands of miles without ever feeling ABS or TC.  It's so easy to test them both on any patch of dirt to learn what they feel like.  ABS can be tested even easier...just stab the rear brake on any road, at any speed...You'll feel the ABS in the pedal, much like a car.  It won't skid, it's not dramatic at all...completely no big deal.  TC takes a bit more work to engage...either try a clutch wheelie in any gear at any speed...it won't get more the a couple inches off the ground.  Or find a patch of sand somewhere and just crank the throttle in first gear.  It will engage immediately, before it even starts to feel like it's spinning, and not be a big deal.

 

There.  Now you all now how and when TC works and how to test it for yourself.

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1 hour ago, DriverDave said:

Let's try and clear this up for you guys...

 

I have experienced TC many times, and verified when I first got the bike that it WILL prevent a wheelie.

The way it functions is to completely cut all power (not sure which way, but I suspect fuel cut).  It IS abrupt and stays off for too long...feels like more than a full second, but never tried to time it.  It does come back somewhat abruptly, because your first instinct when you feel power cut is to give it more throttle.  It's not quite an "on/off" engagement, but it comes back pretty quick...No chance of a high-side.  Our TC system is about as basic as they come.  It uses the ABS rings to detect difference in wheel speed between front and rear.  For that matter, our ABS is quite basic too, but seems to function quite well

 

I don't understand how people ride for thousands of miles without ever feeling ABS or TC.  It's so easy to test them both on any patch of dirt to learn what they feel like.  ABS can be tested even easier...just stab the rear brake on any road, at any speed...You'll feel the ABS in the pedal, much like a car.  It won't skid, it's not dramatic at all...completely no big deal.  TC takes a bit more work to engage...either try a clutch wheelie in any gear at any speed...it won't get more the a couple inches off the ground.  Or find a patch of sand somewhere and just crank the throttle in first gear.  It will engage immediately, before it even starts to feel like it's spinning, and not be a big deal.

 

There.  Now you all now how and when TC works and how to test it for yourself.

 

ABS uses an upgraded system that I had on my CB400. The CB400 you really felt the pulses. On this - you barely feel them - some twitching and it is very efficient. It seems to be a much higher frequency system with very good results.

 

TC - while it uses the wheel sensors that ABS uses, the similarities end there. From a few years ago, there is an article that explains in layman's terms what happens: https://rideapart.com/articles/motorcycle-traction-control-work

 

3 different ways.

 

At least one of three things will happen as the ECU attempts to prevent rear wheel slip : 1) retard the ignition timing, 2) skip fuel injection on a single cylinder, thereby intentionally creating a misfire, or 3) electronically adjust the throttle (assuming the bike is fitted with an electronic throttle).

 

The VFR almost certainly does 1. and probably 2. as well.

 

http://powersports.honda.com/experience/articles/090111c0814723a2.aspx suggests #2 is in play.

 

I just rana  small test. Rode for a few metres to arm the TC system. While bike was on, put it on centre stand and then engaged first. Front wheel stationary and rear wheel went - TC didn't kick in. I presume it may have a centre stand switch to bypass TC system or something else is going on.

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  I presume it may have a centre stand switch to bypass TC system or something else is going on.


It must because I've had TCS engage when I've ridden off a curb.

But it is a wheel speed sensor so it could be the abrupt change in speed that triggers it and not the gradual build up while on the stand.

Does TCS allow you to do a burnout?
That will also start with both wheels stationary and build speed in the rear.
then you'll know if it's a stand sensor.
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1 hour ago, DriverDave said:

I don't understand how people ride for thousands of miles without ever feeling ABS or TC.  It's so easy to test them both on any patch of dirt to learn what they feel like.  ABS can be tested even easier...just stab the rear brake on any road, at any speed...You'll feel the ABS in the pedal, much like a car.  It won't skid, it's not dramatic at all...completely no big deal.  TC takes a bit more work to engage...either try a clutch wheelie in any gear at any speed...it won't get more the a couple inches off the ground.  Or find a patch of sand somewhere and just crank the throttle in first gear.  It will engage immediately, before it even starts to feel like it's spinning, and not be a big deal.

 

That's one of the first things I test when piloting a new vehicle, two wheels or four.  Crazy not to.  You need to know what to expect when the worst happens.

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16 minutes ago, Rectaltronics said:

 

That's one of the first things I test when piloting a new vehicle, two wheels or four.  Crazy not to.  You need to know what to expect when the worst happens.

 

Exactly.  And of course that first ride/drive is after you  'Read The Fucking Manual'  :fing02:

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3 hours ago, armod said:


 

 


It must because I've had TCS engage when I've ridden off a curb.

But it is a wheel speed sensor so it could be the abrupt change in speed that triggers it and not the gradual build up while on the stand.

Does TCS allow you to do a burnout? emoji48.png
That will also start with both wheels stationary and build speed in the rear.
then you'll know if it's a stand sensor.

 

It’s not a stand sensor. If you’d have read the other post it’s activated from the abs rings on the wheels. 

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The traction control uses the front and rear wheel speed sensors. The same ones used on the ABS.  It detects the difference in wheel spinning rates between front and rear wheels and also as far as I can remember the last reading on that wheel. 

It will allow you to run up the gears on the centrestand , but cuts in when you have it in gear and try and push it up a ramp on wet grass as the wheel starts to spin. 

The ecu calculates the speed difference between front and rear and calculates whether TC is needed. If it is it calculates how much torque is needed to stop slippage and reduces the fuel supply accordingly

 

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I've had two accidental wheelies. One downtown lined up at a stop light next to a HD, needed to get in to his lane for the next left turn. Spun the go handle a little much and the front tire came up about a foot. No big deal.

The second was riding the Black Canyon of the Gunnison River in CO while passing a slower vehicle; the front came up several feet as I swung left while pointing to the opposite side of the road, at 45 degrees to the direction of travel. Whatever I did was unconsious but the bike came down pointed the right direction. Slightly not a big deal, surprisingly.

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I did a power wheelie from a stop light. The traction control was on. The front when up about a foot, the TC kicked in flashing light and all. The front of the bike went down. I’d say it prevents wheelies but I’m going to try turning the TC off and see what happens. Fun!

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7 hours ago, Sparticus said:

I "power" wheelied my Vtec once. By simply giving it more than I usually would on new tarmac, with a top box stuffed with my Laptop and a few other bits. The ABS fault light came on....

 

That definitely should not happen.

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Unless its wet out I turn off the traction control every time I start the bike, just habit now, the TC is very sensitive IMO and tries to kick in crossing railroad tracks at full throttle etc, I love that I have it for rain, but outside of that it's awesome you can turn it on or off at any point even when riding. :cool:

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