OEM Brake Pad replacement???

[peperino]

Brake has improved a lot, but the pulsating issue remains

[Juanro]

Welcome to the dark side! Did you left the spring piece inside the caliper? Have you seated the pads yet?

[peperino]

Originally Posted by Juanro

Welcome to the dark side! Did you left the spring piece inside the caliper? Have you seated the pads yet?

I had to remove that piece otherwise the pad would not fit. I think they are pretty much seated at this point, I believe the stock pads are hard as rock that's why they take long to seat

[SpudRider]

Originally Posted by peperino

Brake has improved a lot, but the pulsating issue remains

The pulsating front wheel is caused by a brake rotor which has uneven thickness.

[SpudRider]

Originally Posted by Juanro

Welcome to the dark side! Did you left the spring piece inside the caliper? Have you seated the pads yet?

Originally Posted by peperino

I had to remove that piece otherwise the pad would not fit. I think they are pretty much seated at this point, I believe the stock pads are hard as rock that's why they take long to seat

Is it possible to modify the spring, or only remove half of it? Do you notice any brake chatter without the spring? Do the FA185 brake pads contact the same part of the brake rotor?

[peperino]

Originally Posted by SpudRider

The pulsating front wheel is caused by a brake rotor which has uneven thickness.

I wonder why Zongshen doesn't have better quality control on this thing. You can get away being lazy in some areas but man, it's the brake, it's important!

Also, there are lots of users with this issue here @ Arg. It's not a isolated issue

[SpudRider]

Originally Posted by peperino

I wonder why Zongshen doesn't have better quality control on this thing. You can get away being lazy in some areas but man, it's the brake, it's important!

Also, there are lots of users with this issue here @ Arg. It's not a isolated issue

I agree. There are a lot of RX3 owners in the United States who also have a pulsating front brake. However, CSC honors the warranty, and is replacing the front brake rotor for no cost. Once the defective, front brake rotor is replaced with a good rotor, the problem disappears.

Zongshen doesn't manufacture brake rotors. Apparently Zongshen got a bad batch of front brake rotors from its supplier.

[Riceburner]

Originally Posted by SpudRider

I agree. There are a lot of RX3 owners in the United States who also have a pulsating front brake. However, CSC honors the warranty, and is replacing the front brake rotor for no cost. Once the defective, front brake rotor is replaced with a good rotor, the problem disappears.

Zongshen doesn't manufacture brake rotors. Apparently Zongshen got a bad batch of front brake rotors from its supplier.

This is the same case as the carburetor problem I was experiencing. Zongshen doesn't make the carb's, the supplier had a batch with manufacturing defects, not all carbs, but many. Here my Motorstar, Zong dealer came through on the warranty.

I had recall's on two of my BMW, F650's and we all know all manufactures have some problems, it's a matter of the manufacture and dealer responding to the problem and making it right and the customer happy.

[Juanro]

Originally Posted by SpudRider

[Is it possible to modify the spring, or only remove half of it? Do you notice any brake chatter without the spring? Do the FA185 brake pads contact the same part of the brake rotor?

If you look at the replacement pad it has only one tab in the back, those are tha tabs that are pressed by that spring. I tried to modify (a.k.a. bend) the tabs so it only presses one of the tab, but it's supported on the caliper body in the middle and when you put on the pads, the other side pivots back and it touches the disc edge. I removed it altogether and haven't noticed any strange noise, nor chatter or vibration at all.

The new pads touch about the same area as the old ones, perhaps a couple mm more to the inner side of the disc.

I measured my disc thickness all round with an analog, dial caliper good to the 1/100 of mm and it was between the tolerance of the instrument, i mean: thickness variation was about or lower than 1/100 mm. But it still pulses.

[Weldangrind]

Originally Posted by Juanro

I measured my disc thickness all round with an analog, dial caliper good to the 1/100 of mm and it was between the tolerance of the instrument, i mean: thickness variation was about or lower than 1/100 mm. But it still pulses.

Like this, with a magnetic base?

[keithmaine]

Originally Posted by Weldangrind

Like this, with a magnetic base?

What Weldandgrind is checking is runout and that is really what we are concerned with static measuring will give you some idea if a part will have run out but an indicator measuring a rotating disk will give you truly what you need to know. Also calipers have graduations down to 1/100mm but that is not their accuracy no set of calipers on earth are that accurate nor are the humans squeezing them, for that you would need good quality micrometers. But with that said if you have no visual deviation with your calipers in thickness you can still have disk run out, many brake disk get over heated and warp. If the stock pads are hard they can cause over heating of the disk causing the warped disk to pulsate causing the issue.

[SpudRider]

Originally Posted by Juanro

If you look at the replacement pad it has only one tab in the back, those are tha tabs that are pressed by that spring. I tried to modify (a.k.a. bend) the tabs so it only presses one of the tab, but it's supported on the caliper body in the middle and when you put on the pads, the other side pivots back and it touches the disc edge. I removed it altogether and haven't noticed any strange noise, nor chatter or vibration at all...

Thank you for replying with that good information.

Originally Posted by Juanro

...The new pads touch about the same area as the old ones, perhaps a couple mm more to the inner side of the disc...

The EBC FA125 brake pads are 2 mm narrower than the EBC FA185 brake pads. The FA125 brake pads would probably imitate the original brake pads more closely, but I don't see a problem with getting a little extra bite on the disc rotor.

Since both my Honda XR650L and Honda CRF250X employ the FA185 brake pads, I have a new, spare set of these front brake pads handy. I will install them in the next few days, and give them a test ride, myself.

[SpudRider]

Even without a dial indicator, you can tell if the brake rotor has excessive runout. Just look for uneven wear on the brake rotor.

I received a new, front brake rotor from CSC, and it eliminated the pulsating front brake. However, I still have a little uneven wear on my front brake rotor. In contrast, my rear brake rotor is wearing perfectly evenly.

[Juanro]

Hi, as mentioned above, I didn't measured runout but thickness, using this (picture attached). It consistently showed 3.92~3.93 mm thickness in various points around the disc.
To check for runout I don't have the right instrument. I layed the disc flat over my marble countertop and over a thick glass piece I have over my workind desk, and couldn't detect any click when gently pressing around, so I called it good

[Juanro]

What I DID notice is that some of the supporting bolts are either misaligned or the hole is just a bit smaller than needed. When putting the disc back I couldn't get the bolts to seat by hand before torquing, even when I was using extra caution and doing it in a cross pattern and so on; I wonder if this is putting some uneven tension on the disc when mounted and causing it to warp or distort ever so lightly.