Slow speed maneuver & LBS?

Hello everyone. Sold my wifes Ninja 250 today and soon to sell my beloved modded 919 for a 6th gen VFR. Hopefully HeliBars will help bridge the ergos. So hello & first post here.

I usually drag my rear brake when performing slow uturns and maneuvers. Question is if the brakes are linked and I am in a heavy lean and I tap a bit of rear brake won't that grab a pinch of front which would make it easy to drop the bike. Basically what happens if you have ever tried to use front brake in a uturn.

 

Im on a 5th gen, but I think the linked brakes operate the same. Brakes will engage 2 pistons on the rear and 2 on the fronts. Fronts will engage 4 on the front and 1 on the rear (correct me if Im wrong).

When I was on the MSC, they taught us to drag the rear brake to do low speed maneuvers for parking lots etc. On a CBR125, it was super easy. On a follow up session they offered, when I had my VFR, I had a bell of a time doing the same maneuvers through those tight cones. I still chock that up to inexperience, but I found it much more difficult to deal with. Most of the instructors didn't understand linked braking either so they were puzzled as to why I had such a hard time with the turns. When im leaving the army base after work the traffic gets backed up a lot and I use the back brake and feather the clutch to maintain a 2-3kph roll and usually don't have any problems keeping the bike straight.

I know the 5th gen is super maneuverable when you have considerable experience with throwing the bike around, I saw some of the Tokyo police force demonstration videos and they are doing some amazing things with those bikes at lower speeds.

 

Once you get used to the bike, you shouldn't have any problem with slow speed maneuvers. I drag the rear in slow speeds and feel no difference on the VFR than my other bikes I have/had.

 

Engaging only the rear pedal will apply so little to front braking as to be imperceptible. I know LBS sounds a little sketchy, but it's not even remotely close to using the front brakes mid-corner in either a fast or slow speed maneuver. Under normal riding, I actually find that the LBS is very helpful in keeping the chassis settled as there is just enough stopping power on either the front or rear to help the opposing suspension stay level. May not be ideal on the track for a professional rider, but I think it makes perfect sense in the real world.

Welcome, and enjoy the new ride!

 

The Linked Braking Systems on the 5th and 6th gen. machines are two entirely different animals Merc. They're similar my friend,but they definitely are not the same.
The 5th gen. design has more parts,is bulkier,and is a lot more of a clusterf:censored:k.
The 6th gen. design is more streamlined and simplified.

When you squeeze the front brake lever on the 5th gen. bikes you're actuating the outer two pistons on both front brake calipers. When the left front brake pads squeeze against the rotor the entire left front brake caliper mount rotates up toward the fork leg (The front wheel MUST be rotating forward in order to accomplish this.) and actuates the secondary master cylinder which in turn sends flow to the proportional control valve. The proportional control valve is used as a flow restricter to control the amount of flow in the rear brake system. By controlling the amount of flow you can regulate the amount of clamping force that the brake pads can apply to the rotor. That proportional control valve is very important because the front brake system is very powerful and when you squeeze the front brake lever you don't want it to lock-up the rear brakes. Honda only wanted to apply "some" force to the rear brakes but not enough to lock them up entirely while applying the front brake. That's why that valve is installed in the system. Once the restricted flow leaves the proportional control valve it actuates the center piston in the rear brake caliper.



When you squeeze the front brake lever on the 6th gen. bikes you're actuating all three pistons in the right front brake caliper and the two outer pistons in the left front brake caliper. The left side brake pads squeeze against the rotor and the entire left front brake caliper mount rotates up toward the fork leg (Once again the front wheel MUST be rotating forward in order to accomplish this.) and actuate the secondary master cylinder,which sends flow to the proportional control valve,which then actuates the center piston in the rear brake caliper same as on the 5th gen. bikes.



As you can see Merc the 5th and 6th gen. front brake systems are fairly similar in their layout,the rear brake systems however are where it all gets really interesting.

When you depress the rear brake pedal on the 5th gen. bikes you divide the flow from the rear master cylinder and half of it goes to actuate the outer two pistons in the rear brake caliper. (The flow to those two outer pistons is unrestricted,and that's VERY important I'll get to that in just a minute.) The other half of the flow goes to one end of the delay valve and then goes on to actuate the center piston in the left front brake caliper,which then starts the whole process again of actuating the center piston in the rear brake caliper.

The way I understand it the delay valve is pressure actuated,which means that when the pressure in the rear brake system builds to a specific preset point the delay valve will then open and allow flow to actuate the center piston in the right front brake caliper. The harder you press down on that rear brake pedal the sooner that's going to happen. This was done so that presumably when the rear brakes were applied the left front brake caliper would actuate and the front forks would dive gently,then after a short delay the right front brake caliper would actuate and the forks would again dive gently so as not to unsettle the rider or upset the handling of the machine.

The reason why that unrestricted flow to those two outer pistons in the rear brake caliper is so important is those two pistons can clamp the brake pads against the rotor with all the full output fury that the rear master cylinder can muster,whereas the inner piston (because it's regulated by the proportional control valve) can only provide just "some" small amount of clamping force.



When you depress the rear brake pedal on the 6th gen. bikes you once again divide the flow and half of it goes to actuate the outer two pistons in the rear brake caliper. HOWEVER,on the 6th gen. bikes that flow first must pass through a proportional control valve that restricts the amount of flow to those two pistons,which means that they will now provide less overall braking force than they ultimately could. (Once again that's VERY important,I'll get to why that is in just a minute.) The other half of the flow on the 6th gen. bikes goes directly to the center piston in left front brake caliper. Unlike the 5th gen. bikes there is no delay valve in the 6th gen. Linked Braking System. Once again as the left side brake pads squeeze against the rotor you start the whole process of actuating the center piston in the rear brake caliper.

The reason why that proportional control valve that's inline with the outer two pistons in the rear brake caliper is important is that by doing this Honda has partially neutered the rear brake on the 6th gen. bikes. Since the flow paths for all three pistons in the rear brake caliper now run through proportional control valves those pistons will all provide less overall braking force than they could have if their flow paths were unrestricted. That was supposed to have been done on the 6th gen. bikes to make it "less easy" for the rider to lock up the rear brakes during heavy rear brake applications.




The 5th gen. bikes it would seem placed more emphasis on the front end of the bike while using the rear brakes. The flow to the outer two pistons at the rear was unrestricted providing good stopping power out back,but at the same time you brought two pistons into play at the front which would make the front end hunker-down and dive during heavier rear brake applications.

The 6th gen. bikes on the other hand seemed to place much less emphasis on the front end of the bike while using the rear brakes because only one piston at the front is brought into play. Curiously though it seems that Honda also placed less emphasis on the back end of the bike too while using the rear brakes. By partially neutering the rear brake you have less overall rear braking power at your command. That's a conundrum to say the least.

Sorry for the long-winded explanation Merc but the 5th and 6th gen. Linked Braking Systems are kinda complicated.

My apologies also to Backwards1,sorry for jacking your thread. :sorry: Hope you learned something here.

There is one ridiculous myth about the 6th gen. Linked Braking System that I'd like to put to rest. I've heard it said before by other forum members that it's possible to use the rear brake without actuating the piston in the left front brake caliper. The theory is that by just gently touching the rear brake pedal you'll only actuate the rear brake and won't actually actuate the front brake at all. I'm sorry to say it but that is just a complete load of baloney.
Unless you physically clamp off the hose from the rear master cylinder to the left front brake caliper (or completely remove the entire overly complicated mess which makes up the LBS system from your bike like I did) that just ain't happening. The Laws of Hydraulics say otherwise.

The first Law of Hydraulics states that "Flow Makes It Go". When you step on your rear brake pedal or squeeze on your front brake lever you are moving brake fluid from the reservoir out into your brake system. By doing either one of these simple actions you my friend are creating Flow.
According to the Laws of Hydraulics,when you have more Flow you get more Go,when you have less Flow you get less Go,when you have no Flow you get no Go.
The flow path from the rear master cylinder to the left front brake caliper on the 6th gen. bikes is a direct path,that center piston in the left front caliper gets full unimpeded Flow at all times.
The flow path from the rear master cylinder to the rear brake caliper on the 6th gen. bikes however has a roadblock in it,the proportional control valve. It is a "flow restricting" device. Remember those pesky Laws of Hydraulics here people,more Flow more Go,less Flow less Go.
It really doesn't matter at all how gently you press on the rear brake pedal,you will ALWAYS actuate that piston in the left front brake caliper simply because it gets more Flow. "Flow makes it Go",that's how Hydraulics works.

 

When I did our Advanced Riders Course on my Gen 5 here in '05 found the CBS did make slow speed tight witch hat maneuvers initially a little awkwarder than a non CBS bike would have been but once used to it after practice found it a non issue. ie was able to perform the same course slower than many non CBS bike riders on similar class bikes could.

One advantage I like about CBS on ST motorcycles eg VFR, CBR1100xx etc is they allow you to be a little lazy staying longer on the balls of your feet for clearance over long distance flip flopping twisties using front brake lever only.

Cheers, knew the my previous 6th Gen CBS had a slightly better feeling bias than my current 5th Gen but would never have guessed they were that different.

 

Thanks for the info on how the brakes work.

i think what everyone is saying about the low speed braking is that it takes some getting used to and once the feeling is learned, it should be pretty easy to ride the back brake to deal with the slow/tight turns.

 

I have had my 5th gen for a couple of years. I can say that I really don't notice that much of a difference in braking in regards to riding style between my VFR and my 954. The 954 binders are a lot better then the VFR but other than that, I don't use the brakes any differently with one exception. If I want to stop very quickly I use both front and rear brakes on the VFR. The front brake alone cannot pick up the rear tire, at least it hasn't been able too for me. The front rotors can lock and the front tire will slide (straight if I am going straight). With the 954, I can definitely pick up the rear tire with the front brake, so there is no need to use the rear.

 

It depends on what you mean by "better"... I will agree that the 954 brakes (and my RC51 brakes) FEEL much better and seem to stop the bike much more quickly. The VFR brakes seem wooden by comparison.
However when you check the stopping distances, somehow the 5th G VFR stops more quickly than my RC51! It seems unbelievable, but thats what the numbers say.
I just tried to find a link to back this up, and for some reason it is very difficult to find stopping distances. I know Motorcyclist used to publish them in each issue....

BUT Look at this that I DID find, very interesting study done on ABS/CBS vs non-equipped bikes:
http://www.msf-usa.org/imsc/proceedings/a-green-comparisonofstoppingdistance.pdf
If you don't care to read the long report, here is the gist:
- They tested a 2002 VFR800 with and without ABS
- On average, the ABS systems reduced stopping distance by 5% (in cases where road is wet and bike is fully loaded, it gets closer to 10%)
- The VFR was the only bike with COMBINED brakes (CBS) and it helped to reduce stopping distances (in addition to ABS), especially in the Rear-Brake-Only tests.
Cool!

 

I think I will just respectfully disagree with you on this and move on. No hard feelings bud.