Brake Lock-ups

[Jaws]

Nooooooooo... Sorry Skippy, your sort of missing ( my not too well worded )meaning !
Given the brakes are linked, if you grab a big handful of front ( and I mean a big handful ) the back will be almost off the ground.. With almost no weight on it even the lightest touch would have the wheel stopped.
The only way this could be avoided is to fit abs on the thing...

 

[EdCBRCastrol]

Mine locks occasionally under heavy braking and is usually assisted by a downchange on the approach to a corner, gets quite interesting when the back is weaving and you need to turn!!! There are also a couple of bumpy roundabout approaches near me that regularly get the front tyre chirping as it decides wether to lock or not.
I think the back locking is unavoidable with the linked brakes as explained by jaws, but also your position on the bike would make a huge difference, if you are leant forward under heavy braking you will only add to the effect with more weight over the front= more rear applied,and less weight on the rear,sitting more upright under braking would help IMO.
I find the linked brakes to be ok but then i havent got loads of experience behind me on normal brakes, if the linked system really bothers people then just de-link them, problem solved!!!!

 

[skippy]

Nooooooooo... Sorry Skippy, your sort of missing ( my not too well worded )meaning !
Given the brakes are linked, if you grab a big handful of front ( and I mean a big handful ) the back will be almost off the ground.. With almost no weight on it even the lightest touch would have the wheel stopped.
The only way this could be avoided is to fit abs on the thing...

Nah mate got the gist ok as your only quoting the laws of physics after all :}

Doesn't require that much of a handfull either as I can manage it with just two fingers.

I just think they could have done a better job on the design of the CBS as it is relatively simple to use a torque actuated proportioning valve to progressively reduce the rear brake bias as the front braking effort increases ....... not exactly rocket science.
or better still offer the bird with conventional brakes as a option.

:beer:

 

[skippy]

Mine locks occasionally under heavy braking and is usually assisted by a downchange on the approach to a corner, gets quite interesting when the back is weaving and you need to turn!!! There are also a couple of bumpy roundabout approaches near me that regularly get the front tyre chirping as it decides wether to lock or not.
I think the back locking is unavoidable with the linked brakes as explained by jaws, but also your position on the bike would make a huge difference, if you are leant forward under heavy braking you will only add to the effect with more weight over the front= more rear applied,and less weight on the rear,sitting more upright under braking would help IMO.
I find the linked brakes to be ok but then i havent got loads of experience behind me on normal brakes, if the linked system really bothers people then just de-link them, problem solved!!!!

Totaly agree mate I move my weight forward or back and upright depending on whats appropriate without even thinking about it, I had a Guzzi with linked brakes and can't recall ever locking the rear with the front lever and I used to push it rather briskly as well.

I guess the CBS and me just don't get along I can forsee a de-linking coming along.

 

[Jaws]

or better still offer the bird with conventional brakes as a option.

:beer:

Dont be daft Skippy, that would be far too easy !
Mind you, I actually love the linked brakes. Dunno if they have saved me or not in the past but I do know they have stopped me bloody quick !

 

[tailgator]

When I have been riding alone on the bird there has never been a problem (caused by the bike!) but I did notice on a trip out to Maleny (near Brisbane, Australia) when I had my sister on the back the back locked very slightly at one set of lights. I'm very heavy - 130kgs and my sister would be about 70kgs so the bike was very loaded up. Was the first time I've ever locked it up on this bike and was only using the front brake, until the last second! :t

 

[Stuey]

Hi Chaps,
How about this for a "theory".
The 'Birds brake system is fitted with a PCV (Proportional Control Valve). The object of this valve is to sense deceleration forces and limit the amount of pressure being fed to the rear calliper. The way I see it, is that if you apply the front brake gently at first, the PCV will sense the deceleration and start to limit the flow of fluid to the rear calliper. If you the increase the braking force, very little if any of this will then be relayed to the rear calliper because the PCV will of interrupted the circuit, so no rear lock up should occur, unless the rear wheel is completely unloaded.
Now, if you suddenly pull a great big 4 fingered handful of front brake, some of this pressure will be fed to the rear calliper before the PCV has time to sense deceleration and act upon this, so the rear calliper will already be braking hard, then as all the weight transfers forward the rear wheel can't transfer enough of the force through to the ground and will lock up. The PCV can only stop the flow of fluid/pressure, it cannot relieve pressure once it has been applied.
I feel that if you do have a rear lock up it is either because of the above scenario, or because your PCV is faulty/sticking.
If you are getting rear lock ups on a regular basis, try altering your initial braking technique, and see if it helps.

*I reserve the right to be wrong.

Stuey

 

[richard]

It would be intresting to see if Honda come up with an ABS system, when or even if they update out babies..Used one on a bemmer the other week on a test run with no probs.


R

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