Front brake issue

[Ernest]

Anyone experienced a slight hop from the front brakes when slowing down? It's only begins to be evident at a speed  of 5kph to stop. To date I have deglazed the rotors, sanded the pads, cleaned the buttons, checked to make sure the pistons are free, loosen off the front wheel axle and retorque. Normal braking at higher speeds is perfect but becomes very annoying when in traffic.

[betoney]

29 minutes ago, Ernest said:

Anyone experienced a slight hop from the front brakes when slowing down? It's only begins to be evident at a speed  of 5kph to stop. To date I have deglazed the rotors, sanded the pads, cleaned the buttons, checked to make sure the pistons are free, loosen off the front wheel axle and retorque. Normal braking at higher speeds is perfect but becomes very annoying when in traffic.

Not sure what you mean by "slight hop"?  At that speed (3mph) it sounds like it is happening right as the wheel is on its final rotation coming to a complete stop?

[Ernest]

Correct, feels like an out of  round/oval wheel but only experience it when braking with the front brakes. Tried slowing down using the rear brakes and no brakes and don't experience this slight hop. 

[texscottyd]

Hi @Ernest - I know exactly what you're talking about, since mine does it too.   I've swapped to the 320mm EBC rotors, and get that slight low-speed pulse from the front brakes when coming to a stop.    The brakes work great at higher speeds, with no vibration or shaking...  I'm convinced it isn't a warped rotor or bent wheel.  

I am getting ready to install a set of Galfer steel lines, and will do a complete brake system flush and bleed at that time.   I'm hopeful that takes care of the problem, but if it doesn't I will definitely dig into it a bit deeper to find the root cause.   If you figure it out before I do, please let us know.  

Good luck.  I'll keep you posted on what I find...

[BBB]

@texscottyd, I think with your set up (and uprated pads?) what you’re feeling is the result of the pads being hot. Uprated pads can be grabbier when hot, and you don’t sense the effect with higher rotational speeds. But, as you come to a stop the effect becomes more pronounced as the wheel slows down i.e. just before you come to a stop. It will feel like a pulsing effect as the pads grip tightly then  let go a bit.

Of course, that’s why you get better braking with HH pads. The only way to alleviate it is to do the majority of your braking with the front brake and then swap to the rear brake as you come to a stop.

[texscottyd]

@BBB - That does make sense.  I have the HH pads matched to the big EBC rotors, and they work really well at speed... much better bite and feedback than stock.   The slow speed pulsing is a minor irritation, and it does seem to come and go based on how aggressively I’ve been using the brakes.   Given your theory, that actually does make sense.   

I don’t do much commuting or city riding, so it hasn’t been too much of a bother for me.   It will be interesting to see if there’s a noticeable improvement with the new lines & fresh brake fluid.   

[Ernest]

Thanks for all the advice, as I have just recently purchased this bike I will need to have another look at the type of brake pads fitted. It may well also have hh pads. 

[betoney]

8 hours ago, Ernest said:

Thanks for all the advice, as I have just recently purchased this bike I will need to have another look at the type of brake pads fitted. It may well also have hh pads. 

Just my opinion but if you are upgrading your pads, you DO NOT need to put HH pads on the rear, it is already relatively easy to activate ABS on the rear.  The HH pads are a great upgrade for the front though.

[2and3cylinders]

+1 on NOT using HH+ pads in the rear (OEM are GG).

The hop or skip you generally described actually could be the front ABS momentarily kicking in when you are brake and go over a ripple, sharp edge or even a slight bump.  The ABS reduces pressure when the tire goes airborne and the wheel speed drops in relation to the rear, then restores full breaking force when the tire grabs again.  It can happen very quickly and the hand brake lever may or may not pulse at that frequency, or the pulse may be masked by the OEM suspension's somewhat excessive high-speed compression damping and lowish rebound damping.  Playing with road-tire pressure ration, and adjusting spring preload and rebound (and compression one has it), plus learning to modulate brake pressure for road conditions should help.  Of course a weight tailored set of fork springs and massaged cartridges, and a taste 3 or 4-way shock with the correct spring rate all dialed-in properly will do wonders too.  😎

[Ernest]

Thanks, but definitely doesn't feel anything like ABS coming on. I have had the suspension professionally setup for my weight and has made no difference.  As mentioned before it is only noticeable at almost stopping speed 10 - 15kph. I am now getting good at using my rear brake for the last 4 metres until I can find a solution. 

[roadrash83]

3 hours ago, Ernest said:

Thanks, but definitely doesn't feel anything like ABS coming on. I have had the suspension professionally setup for my weight and has made no difference.  As mentioned before it is only noticeable at almost stopping speed 10 - 15kph. I am now getting good at using my rear brake for the last 4 metres until I can find a solution. 

 Did you replace the brake pads? 

Did you bring up the problem with your suspension expert?

[Paddy01]

Hi All

I’m new to the forum. I have a 2018 900 GT bought new which had the front brake problem. To cut a long story short; Yamaha replaced both front disks under warranty because they were warped. Seems to be a manufacturing fault and I’m sure some choice words were used by Yamaha when they addressed it with their rotor supplier. 

Loving the forum and have learned so much from everyone’s experiences. Especially the seat debacle. 

[betoney]

6 hours ago, Paddy01 said:

Hi All

I’m new to the forum. I have a 2018 900 GT bought new which had the front brake problem. To cut a long story short; Yamaha replaced both front disks under warranty because they were warped. Seems to be a manufacturing fault and I’m sure some choice words were used by Yamaha when they addressed it with their rotor supplier. 

Loving the forum and have learned so much from everyone’s experiences. Especially the seat debacle. 

My front brake issue was kind of the opposite, instead of warped front rotors, my front calipers and pads were replaced under warranty due to very bizarre wear patterns on the pads.  I haven't had a front brake issue since, love the Y.E.S. warranty coverage.

Glad to hear that they took care of you and you are back on the road.