Gen II Linked brake system

Can't find anything in the FAQ, so here goes: I know that application of the rear pedal activates one of the front calipers, but *somewhere* I read that very firm application of the front lever will activate the rear brake caliper.

1. Is this true?

2. If so, where is it documented?

TIA,

BentAero said:

Can't find anything in the FAQ, so here goes: I know that application of the rear pedal activates one of the front calipers, but *somewhere* I read that very firm application of the front lever will activate the rear brake caliper.
1. Is this true?

2. If so, where is it documented?

TIA,

Click to expand...

1. No

2. It's not

At least not according to my owners and service manual. The linking is very well explained in the service manual.

Standard equipment Unified Braking System w/ABS: The front brake lever activates six of the eight front braking pistons and two rear pistons; the rear brake pedal activates two rear pistons and the other two front pistons—for balanced anti-lock braking in all conditions.

Taken fromYamaha USA

1 its true

2 see above for documentation

Actuating the front brakes has no effect on the rear brake. It only actuates 6 of the 8 front caliper pistons.

Actuating the rear brake also actuates the other 2 front caliper pistons. There is a linkage only when the rear pedal is depressed.

FJRFencer said:

Standard equipment Unified Braking System w/ABS: The front brake lever activates six of the eight front braking pistons and two rear pistons; the rear brake pedal activates two rear pistons and the other two front pistons—for balanced anti-lock braking in all conditions.

Taken fromYamaha USA

1 its true

2 see above for documentation

Click to expand...

BINGO!

Constant Mesh said:

Actuating the front brakes has no effect on the rear brake. It only actuates 6 of the 8 front caliper pistons.
Actuating the rear brake also actuates the other 2 front caliper pistons. There is a linkage only when the rear pedal is depressed.

Click to expand...

Wrong

Constant Mesh said:

Actuating the front brakes has no effect on the rear brake. It only actuates 6 of the 8 front caliper pistons.
Actuating the rear brake also actuates the other 2 front caliper pistons. There is a linkage only when the rear pedal is depressed.

Click to expand...

OK, which is it? The diagram in the service manual sure looks (to me) like it goes both directions.

Why is it that under hard front braking you can feel the rear brake pedal drop? Of the two FJR's I've rode, they both did this...

Here's what Yamaha's web site says:

"Standard equipment Unified Braking System w/ABS: The front brake lever activates six of the eight front braking pistons and two rear pistons; the rear brake pedal activates two rear pistons and the other two front pistons—for balanced anti-lock braking in all conditions. "

The online owner's manual doesn't mention it or I missed it.

Regards,

-GSE-

FJRFencer said:

Standard equipment Unified Braking System w/ABS: The front brake lever activates six of the eight front braking pistons and two rear pistons; the rear brake pedal activates two rear pistons and the other two front pistons—for balanced anti-lock braking in all conditions.

Click to expand...

+1

This is correct, the linked brakes work both ways.

No they don't.

From the service manual:

The Yamaha unified brake system is a system that operates one set of pistons in the front brakes together

with the rear brake when the brake pedal is depressed. Compared to conventional brake systems,

the ability to slow the vehicle using the simple operation of the brake pedal is improved.

When the brake lever is squeezed, both sets of pistons in the left front brake caliper are operated, but

only one set of pistons in the right front brake caliper is operated. When the brake pedal is depressed,

the rear brake caliper and one set of pistons in the right front brake caliper are operated. The brake line

from the rear brake master cylinder is split at the hydraulic unit to transmit brake fluid pressure to both

the rear brake caliper and part of the right front brake caliper in the unified brake system. The brake

fluid pressure transmitted to the rear brake caliper and part of the right front brake caliper is controlled

by the proportioning valve and metering valve respectively. The operation of these two valves ensures

that the braking feeling of conventional brakes is maintained when a small amount of force is applied

to the brake pedal, such as when making U-turns, and prevents early locking of the rear wheel when a

large amount of force is applied.

Metering valve

This valve prevents the brake fluid pressure that is transmitted to the right front brake caliper from increasing

until the pressure exceeds a set level. Only the rear brake caliper is operated when there is

an extremely low amount of brake pedal input.

Proportioning valve

This valve reduces the increase in brake fluid pressure that is transmitted to the rear brake caliper when

the pressure exceeds a set level. The increase in brake fluid pressure to the rear brake caliper is controlled

when there is a high amount of brake pedal input.

Standard equipment Unified Braking System w/ABS: The front brake lever activates six of the eight front braking pistons and two rear pistons; the rear brake pedal activates two rear pistons and the other two front pistons—for balanced anti-lock braking in all conditions.

Click to expand...

Well, whoever wrote this on the Yammi website must have been asleep at the wheel. Could the service manual be wrong?

I understand that the rear is linked to the right caliper, cause I just bled an AE.

Someone go rev up their bike on the center stand and press the front brake to see if the rear slows down, that will put an end to this discussion.

The USA Yamaha website has never been correct on this issue.

The Canadian Yamaha site has it right:

https://www.yamaha-motor.ca/products/produc...up=M#contentTop

Under Chassis/Suspension:

Unified braking system with computer controlled ABS.

When the front brake is applied, all 4 - LHS front caliper pistons are activated, while only the "upper" two pistons on the RHS front caliper are activated. When applying the rear brake, both rear caliper pistons are activated plus the two lower pistons on the front RHS caliper are activated.

Constant Mesh is 100% correct.

On the FJR1300 (Gen II) LBS System, squeezing the front brake lever does ABSOLUTELY NOTHING to the rear brake whatsoever.

The FJR's Linked Brake System is not a bi-directional 'linked" system, like the LBS system found on the CBR1100XX Blackbird. The FJR's system is only linked rear-to-front.... not front-to-rear.

I have my bike on the center stand and the front break does not stop the rear wheel.

Warchild said:

On the FJR1300 (Gen II) LBS System, squeezing the front brake lever does ABSOLUTELY NOTHING to the rear brake whatsoever.
The FJR's system is only linked rear-to-front.... not front-to-rear.

Click to expand...

Exactly

Thank you all for clearing that up. It's good info to have, even though I lost the argument. <_<

As the rider of an 05 FJR (loved it) for over 22K miles and having totalled it last October I am getting ready to buy another FJR or possibly a Concours 14. I have no experience with linked brakes although my 05 did have ABS which I liked. I do from time to time use trail braking. I have been a bit hesitant to embrace the linked brakes. I have noted as Warchild pointed out that the linked brakes on bikes from different manufacturers all seem to be linked in different ways. BMW's, seem to be linked different than Yamaha's, and Honda's are I believe different in the linking than either of the other two. I would be most interested in comments from riders with experience of the various types. I guess I am a bit concerned about being on a slick surface in a slight curve and by putting pressure on the rear brake having the front go out from under me in a low side manner. Is this a justified concern? If not why not? I realize that this is slightly different from this thread but it is related and the thread question seems to be resolved. Much thanks in advance. Ron

RonBB said:

As the rider of an 05 FJR (loved it) for over 22K miles and having totalled it last October I am getting ready to buy another FJR or possibly a Concours 14. I have no experience with linked brakes although my 05 did have ABS which I liked. I do from time to time use trail braking. I have been a bit hesitant to embrace the linked brakes. I have noted as Warchild pointed out that the linked brakes on bikes from different manufacturers all seem to be linked in different ways. BMW's, seem to be linked different than Yamaha's, and Honda's are I believe different in the linking than either of the other two. I would be most interested in comments from riders with experience of the various types. I guess I am a bit concerned about being on a slick surface in a slight curve and by putting pressure on the rear brake having the front go out from under me in a low side manner. Is this a justified concern? If not why not? I realize that this is slightly different from this thread but it is related and the thread question seems to be resolved. Much thanks in advance. Ron

Click to expand...

Ron

Did you see my thread on my screw up?

here

It clearly shows how good the brakes are on the 06

It clearly shows how good the brakes are on the 06

Click to expand...

Thanks for sharing, I had missed that post. I've ridden the Dragon several times and there are a couple of surprise areas-Glad the road was clear. Have you had any experience with the linked brakes on a slick or wet curve, or on gravel with moderate rear wheel braking only? I'm concerned about the front wheel stopping under those conditions. Ron

Constant Mesh said:

The USA Yamaha website has never been correct on this issue.
The Canadian Yamaha site has it right:

https://www.yamaha-motor.ca/products/produc...up=M#contentTop

Under Chassis/Suspension:

Unified braking system with computer controlled ABS.

When the front brake is applied, all 4 - LHS front caliper pistons are activated, while only the "upper" two pistons on the RHS front caliper are activated. When applying the rear brake, both rear caliper pistons are activated plus the two lower pistons on the front RHS caliper are activated.

Click to expand...

correct....

also of note: Clicky

As indicated by the bike's FJR1300A nomenclature, anti-lock brakes are now a standard feature of every 2006 FJR, upping the base price to $13,499.

Also new is a Unified Braking System, which is Yammie's way of saying linked brakes.

The front brake lever actuates six of eight pistons in the monoblock, differential-bore Nissin calipers, while the brake pedal actuates the rearward two of four pistons in the right front caliper, in addition to the rear brake.

To maintain even pad wear, the brake-pedal-activated front pistons are smaller and bite on smaller pads than the other three pairs.